Odd normal vol channel..

[The Captain]

Hi- sorry me again, enjoying my 5e3 handiwork- BUT Q re normal 'bassy' vol/ no gain.. the normal vol seems like a 'bass pot' rather than adding anything useful to the bright vol, & also I can't get any gain at all (albeit not cranked, but jamming vol say @2.5 on bright vol adding anything up to 10 say with normal vol pot). Guitar into normal inputs is just 'bassy' without any useable tone whatsoever..

Ive done the cap changes to help (bright pot is ok and useable, really tho only with an EQ pedal's bass end way down) but normal side just sounds like a guitar tone knob at 0- bass only: no use at all). I do have a tad 5y3gt (I get 388v plate V) and a 12ay7 for 1st tube. All other voltages, wiring etc checked and ok.

In short.. 1. is the normal vol meant to be this way?? 2. can I change any other caps else to brighten/ cut any bass 3. Any thoughts on why I cant get gain? (I built it for the overdriven tones!). thanks Captain.

[sportster4eva]

Hey Capn',
That's definitely not the way the normal channel is supposed to sound. It's definitetly not bassy, unless you roll the tone knob back to about 2. The way the two channels interact is that when you're plugged into normal 1 input, turning up the channel 2 volume starts to fatten up the tone as you progress towards 12, and vice versa. I'm thinking maybe you could try only wiring up the normal and bright channel 1 inputs only, like Stokes suggested in the other thread, and see what that does.

[The Captain]

I defo have all 4 inputs wiring ok now, all other wiring too.. have checked voltages: yes high at pin 3 of both 6v6gt's (388v), but others all Id say are reasonable. The only thing I did different is to wire the tone's .0047 cap to gnd lug of adjacent bright vol pot; I can't see that as being cause for this bassy business tho? Ive been advised to switch my cheapo 5y3gt out and my 16uf/ 475v caps are cheapo too- again I cant see either being the cause.. could a sino 12ax7, or a dodgy one (no obviously noisiness mind you) for that matter do such shenanigans? Im sure the normal channel should be only a wee bit 'darker' to the bright as a general rule, so I defo have an oddity here it seems..? Captain.

[RickyD]

Captain-

Before you try anything else, I suggest you take a chopstick and tap on all your solder joints while the amp is on. If the joint makes noise, melt it again. If your problem is a bad solder joint, you'll be done in ten minutes.

If you've got spares, exchange your preamp tubes.

The gain curve should be identical for both channels, the only difference is more treble in the bright channel. I don't understand your description of the gain problem, so let me give you an example. On my 5e3, using a telecaster with vintage style pickups, I reach full volume at 2 - 2.5 on the volume pot. Are you doing that on either channel?

Regards,
Rick

[stokes]

Yeah,Cap'n something aint wired right there.Both my clones are like Rick and sportster described more or less.I would suggest looking at the tone caps,in particular the .0047 you mentioned,I dont think the rectifier or any of the other changes you mention will help this problem,this definately is a problem in the tone/vol circuit,I suspect that .0047 cap is tied to the wrong lug of the volume pot,making the volume act as a tone control,as you describe.

[The Captain]

Cheers folks- oddly that .0047 is tied from tone to the bright vol pot thats sounding, well ok I guess. Ive got correct continuity all around circuit too.. could a dodgy vol pot do this bassy baloney?

[MWJB]

Sportster wrote: "The way the two channels interact is that when you're plugged into normal 1 input, turning up the channel 2 volume starts to fatten up the tone as you progress towards 12, and vice versa."

That's not the way any 5e3's I have worked on behave, nor do I believe that this is normal. Usually, as you get the unused volume (the one you are not plugged into) past halfway (max gain), gain starts to drop off again and the tone cleans up, mids are scooped. This may not be the case, however, if you have converted the volume controls to voltage dividers or installed Bruce Collins' mod.

The difference between the 2 channels in a stock 5E3 is that 500pf cap from the wiper of the Bright vol to the RH tab of the tone, this cap does not feature in the Normal channel and typically makes that channel duller until you get it turned up enough to cut.

However, gain should be about the same for both channels, but the voicing can make this tricky to determine by ear.

To reduce bass further (it sounds like you could do with losing some from the Bright channel too if you need an EQ pedal) I would look at your 25uf preamp cathode bypass caps, you could either replace them both with 4.7uf, or keep 25uf in the first stage (V1) and stick a .68uf (1uf may be easier to find and you don't need to stick to electrolytics, a non-polarised metallised poly cap of 25v rating or better will do) in parallel with the 1500 at V2 pin 3 (keep resistor values the same). Or experiment until you find what suits you. Bass reduction through cathode bypass caps will affect both channels, unless you split the cathodes at V1 and give pin 3 and 8 their own cap & 1500ohm resistor (not usually necessary).

Subbing the 12AY for a 12AX7 will give you more gain, but typically stodgier bass too unless you play with the preamp cathode bypass cap values.

[sportster4eva]

Sportster wrote: "The way the two channels interact is that when you're plugged into normal 1 input, turning up the channel 2 volume starts to fatten up the tone as you progress towards 12, and vice versa."

That's not the way any 5e3's I have worked on behave, nor do I believe that this is normal. Usually, as you get the unused volume (the one you are not plugged into) past halfway (max gain), gain starts to drop off again and the tone cleans up, mids are scooped. This may not be the case, however, if you have converted the volume controls to voltage dividers or installed Bruce Collins' mod.


Sorry for the misconception, what you described is what I meant when I said fattens up the tone. The scooped mids is what does it.

[The Captain]

Ok, Ive ordered a .68uf O drop for that V2 bypass cap, and ill stick the 25uf back for V1 bypass. Ive got both at 4.7uf at the mo, but they made barely any difference to the normal channels bassy bafoonery. Also got a EH 12ax7 ordered so then I can see if either tubes are dodgy, along with 3 Sprague Atom main filter caps, & a SMica 680pf for that 500 tone one. Hope that lot does summat! Ill post results- After that, is an innefficient spkr like a 93db jensen alnico rather than my 100db eminence (which is loud and 'hard' sounding) an idea to hopefully get at least a hint of overdrive?? (or 'gain' as i prob wrongly termed earlier; distortion basically). Many thanks for the tips all. Captain.

[stokes]

Yeah I have always thought of it as a scooped mid thing,but just figured it was sportsters perspective or different way of describing it,didnt seem to matter to this issue,it seems to me that a volume pot acting as a tone control has to be related to the way it is wired as opposed to a tube issue.With a stock 5E3 the distortion should come up rather soon as the volume is turned up to about 3.Does your Bright channel work normal?

[The Captain]

Bright channel sounds ok (tho I still use a boss eq to rid the bass)- but I get zero distortion even with this channel: so say even with a boss eq level at 1, guitar vols down a tad to ratchet the 5e3 to 3ish on the bright vol= still clean as a whistle?!

Incidentally, does anyone know what the addition of a .001 to the 100k as a bypass (from pin 6 of V2) do? perhaps it could help my bass bunyons.

[MWJB]

This will bleed off highs, probably not what you want.

[The Captain]

Ok I'll leave that then MJWB.. if I were to change that .0047 on the tone pot to a .01 say, would that brighten or darken things do you think; is it ok to play about with different bypass caps, tone pot caps etc?

[MWJB]

A larger cap to ground from the tone pot will bleed off more highs, darken the amp.

Play with whatever you want, it's your amp and it's got to do what you need it to do, irrespective of whether or not that's the way it was designed. Typically though tone cap values seem to end up as stock (though some older amps used .0033uf to ground)?

Perhaps another place to look might be the .1 coupling caps that feed the power tube grids, if the amp is too bassy these can go down to .047uf, maybe too bright with a solid body Fender guitar, but this is the kind of value that Gibson used in similar amps.

[The Captain]

Ah thats interesting, that could be my last port of call short of changing the spkr- and thats quite a hassle and expense. It is a twin humbucker sg Im using it for after all so any gibson amp tips may be a way to go- cheers capt.

[RickyD]

OK Cap, this is driving me crazy. The answer is right there waiting to be found. We know that your amp will work correctly if there are no wiring errors, the component values are correct, and you have no defective components.

I wouldn't change component values to correct the tone problem yet. There's a bad component or a wiring error that has to be found. The 5E3 is one of the greatest amps ever, stick with it. There is a community out here that is rooting for you.

If you haven't yet, I suggest you lift a leg on that tone cap you grounded to the bright volume pot. You have one channel that's acting like it has a low pass filter, fixed value and always on. The tone cap, connected wrong, could produce that effect.

Next, I would confirm that each component in the amp has the value specified on your layout diagram. Special care with the resistors and the multiplier bands (470 ohm vs. 470K ohm, etc.). Circle each component on the diagram after it is checked. (BTW, run an extra copy of the layout so you always have a clean one.)

Then, go to each solder joint in turn and confirm that every connection to that joint is as specified in the layout. Circle each joint after you check it. If you have hidden connections under the board, use a multimeter to confirm continuity.

I have done this kind of checking and found the flaw on the fourth iteration. It is so easy to overlook your own mistake...Sorry if I seem too pushy. This just my opinion.

Regarsd,
Rick

[The Captain]

Not too pushy AT ALL- I really value the reply/ tips. It does seem on the face of it to be a simple wiring error, innitially Id almost put money on it being exactly that too but alas alls defo correct: checked over 5x now. I will lift that .0047 cap straight to gnd (tone gnd to bright pot gnd at mo). Just tried a new 12ax7- not that; swapped 3 preamp tubes around too- still same.. am gonna try a .68uf as suggested for V2 bypass cap (* I presume I still keep the 1.5k paralled with it?) next. I'll get there even if it means growing a beard!

[Bruce / Mission Amps]

Something is funny in the way you described that grounding scheme for the tone pot and the bright channel vol pot.
And the way you talk about the lack of gain with respect to the volume pots... I promise you have a bad part or there is something installed wrong, regardless if you checked it 5x! ha ha.
Can you shoot me a digital picture of the three pots and the eyelet board around the preamp stage?
I've done quite a few of these and have not heard this problem yet when the amp is wired correctly and the amp is using three, 1m pots.

[The Captain]

Sure can do Bruce, cheers- Ill rustle up a pic tmrw. Actually ive just reverted back to the .0047 direct to gnd as opposed to tying it between tone's gnd & bright pot gnd lug: exactly the same. So Im now wondering if its just the way its gonna sound on normal channel. Ill next try a replacement pot.. whiskers have sprouted.

[The Captain]

Bruce here's a pic- best my digi cam can muster Im afraid, apologies:
http://i102.photobucket.com/albums/m106/TheCaptain_02/Picture270.jpg
Capt.

[sportster4eva]

In the pic, where's the black lead connect on the first pot? It sort of looks like it goes to the wiper.

[The Captain]

In the pic, where's the black lead connect on the first pot? It sort of looks like it goes to the wiper.

I knew my awful camera wouldn't prove so useful here! the black leads connect from tone [edit] 2nd lug (as viewed here) to bright vol 3rd lug and another to normal vol 3rd lug; the wiring is all correct to the weber layout.

So I spent today rewiring the pots in case of summat, changing the 500pf to 680pf, V2 bypass to a .68uf and all 16uf filter caps with ubiquitous Spragues 475v... without the slightest difference whatsoever! so this is the stock normal channel sound it seems.. a shame really- its completely unuseable as its just too bassy. Still can't hear a hint of overdrive either even with 2 12ax7s (maybe I could if I took out my hearing & half the street and turned it up to 8- Im still not convinced tho). A dissapointment so far this after loads of time and money.. still it does sound pretty good clean I guess.

All I need is a tone, one bright input/vol and a master vol!

[stokes]

Capn,I know you keep saying that it is wired correctly,and I cant tell otherwise from the photo, but the sound you describe tells me something isnt wired right.Either channel should start breaking up at 4 at the most,and one control should not act like a bass control,trying different value components now is futile.I again would advise using just 2 inputs it will simplify that part of the circuit and you had trouble here earlier,then go over the volume and tone circuit with a fine tooth comb,your problem is likely here.

[The Captain]

I gave it a thorough sound test at volume over wknd. Actually it sounded, I hate to say, pretty rubbish really.. very bitty, hard, uncohesive break up that never gets above a tame overdriven sound (starts about 5 and is similarish up to max- it took huge volume to get it, and a series of complaints too!) with a general big hug of bass thats just overwhelming, even on bright channel. Im sure both channels are working as intended as Ive done every check now.. I may change spkr (maybe a single 10"?), my cheapy 5y3gt and my RS 0.1ufs.. but Im wondering if its worth it now. After that its a lost cause I think :( Capt.

[MWJB]

OK don't throw in the towel and get disheartened now. You've probably done the hard work and it's got to be something simple, just not glaringly obvious, that's got you skuppered. Remember that the amp, for whatever reason is just doing what it is (inadvertantly) built to do, it's not being spiteful. Now that you've given it a good blast, it seems that there must be an error somewhere.

Don't worry about the 5Y3GT (it's delivering good voltage, that's not the problem), don't worry about the RS 0.1ufs, they're not the problem. The amp should give it up with the 12" Eminence.

It's not a lost cause, just have a bit more patience. You've built the thing, now you need to hone your trouble shooting skills...this is where the learning really starts!

Voltages & power supply are good, so it's something in the signal path. Eliminate things one at a time.

[MWJB]

They way you have hook up wires soldered to the back of the circuit board looks nice & neat but makes one wonder if everything goes to & from where it should. Power down, drain voltages and work through the layout, double checking for continuity from component to component using your meter set to the lowest ohms setting, highlighting off the connections as you go.

[stokes]

Like MWJB says,dont give up on it now,at worst a properly wired 5E3 should still sound decent,noisy maybe,but not at all like you describe.Hate to sound like a broken record Cap,but something is wired out of whack and you've come to far to give up on it now,I agree with MW that it is likely something simple,just not obvious,and when you do find it you will kick yourself in the butt for not seeing it sooner.That 12" Eminence should be fine with that amp and a speaker change is not what you need now.As well as the advice already given here as far as checking for continuity etc,I would also suggest you check that your coupling and tone caps arent leaking dc,and voltages at the plates and cathodes of the preamp tubes are correct."Actually it sounded, I hate to say, pretty rubbish really.. very bitty, hard, uncohesive break up that never gets above a tame overdriven sound".This description,and again you trying to describe and our perception of what you are describing can be hazy,could also point to power tubes biased cold and giving you the dreaded crossover distortion.But I still feel the tone and response you have been describing is more likely something in the preamp section.I know its tough to track down a problem in a first build,but it is part of the learning process,and all of us throwing different ideas at you can get frustrating,but dont give up,you will get there.

[RickyD]

Hey Cap-

You gotta stiffen up, man. Everybody that builds these things has episodes like this. Every misplace your wallet? Look all over the house, everyplace you can think of, still no wallet. Keep looking, find the wallet in a place you did not think possible - or realize you've been looking at it without recognition for the last 30 minutes. That's just where you are now. So close.

I jerked around with my amp for a long time, weeks. Didn't have a lot of time every day to fool with it. I finally found my problem by beating on it with a stick. No science at all. Tapping on solder joints with the chopstick for 5 minutes, found a cold solder joint, fixed it, and did't stop playing for the next three hours. If science doesn't work, beat on it with a stick!

I sense, using powers acquired in the Orient, there is a mental block forming in you. Fight it off, this is worth it. Arguably the best guitar amp in history in your hands, could be fixed and perfect in the next five minutes if you just keep after it. Sifu taught that when the body fails, it falls. When the mind fails, the body walks away. The point is that you can do this! Don't give up. I want to read about you waking up face down in the chassis. You have to do the work, and do it with an open mind. The odds heavily favor the contingency that there is a readily observable flaw right in front of you.

The fundamentals are not necessarily easy, just fundamental.

Quick recap: Correct component values, wired correctly, will work. No point in insisting it's all correctly wired. It doen't work. Your next post, I expect to see that you have taken your layout drawing and checked the required component
Just my opinion


I know a lot less than many ofn the people who post here. . I don't even know what a V2 bypass is (you changed to .68 uf, no effect).

Shouldn't changing that cap have an audible effect? What other reason to change the value now? So if you change that and can't hear a difference, does that mean maybe no signal is happening there? Should there be? You get the idea.

Did you use stranded wire or solid? If stranded, maybe an wild strand has "wandered" into a short circuit with a neighboring junction. Just for variety, try a continuity check between adjacent tube socket pins, other terminals.

[stokes]

Cap'n,I know you said all voltages are normal,but just to give us a look,would you post the voltages you are getting at V1&V2 pins 1,2,3 and 6,7,8? Power tubes pins 3,4,5,8.Maybe we will see something you are missing.I know we must have your head spinning with all our opinions and such,but bear with us and you'll get it working.

[The Captain]

MJWB kindly went through my voltages with me on the blower t'other day- a wee bit high as ive a £10 5y3; but generally fine he said. I will try and decipher my scribblings tho and post the Vs up Mr.Stokes.

Another evening's effort to sort out: (as suggested- thanks- only other day I spent 10m looking for a pen.. behind my ear!) so I did continuity checks at every possible place, and replaced the normal vol pot & the .02 cap in the normal channel from V1 in case either was dickie. I also rewired my neck humbuck to single coil- which helps a bit: but basically all as was before- all wiring correct/ solders good/ bits in right places/ polarity ok/ poss bad components illiminated now.

One obvious difficulty is not having anything to compare it to, ie a '5e3 clone shop down road' would be handy! all I have is the odd clip from Homebrew and S2 (which sound excellent, with clear distortion and certainly not a bass enveloping normal channel). Can someone tell me.. if plugged into either bright input, with vol at 0, and then introducing say 2 on the normal vol.. can anyone describe the sound heard? I mean if its like mine then Im pissing in the wind, and Im defo stuck with a turkey 5e3. I definitely have a rubbish eminence legend 125 spkr I think- cardboardy, LOUD, one-dimensional and blatty hard overdrive (if I can call it overdrive); of course Im no nearer knowing if I replaced it with say a jensen P12Q (Ive an eye on) things would be a whole lot different. It dont help either when a fender revalved red knob twin goes on fleabay for little more ££s than my concoction!!

[stokes]

No need to post the volts if MJWB said they are okay,then I am sure I wont see anything there.I just went down and checked mine as you described and when plugged into the bright input with that vol on zero or off and turning up the normal volume I get a dull,bassy muddy tone with very little volume and I have to wonder if this is what you have been describing yours sounds like.Again I have to say that speaker should be okay with that amp,I dont think a speaker change is going to help,the first speaker I had in mine had an Eminence Legend and it was fine.A 5E3 that is wired correctly is going to sound decent if not "ideal",and may require some tweaking to get it to your liking,but it will definately not exhibit what you are describing.I still have strong suspicions about your inputs,I hate to sound like a broken record about these inputs but you did have a problem earlier there,to simplify things in that regard I would again suggest disconnecting all your inputs and wire just one input to the brite channel with a 1meg from the "hot" lug to ground,a 68k in series to the input grid of the 12AY7 and the shorting switch grounded.This will make your input as simple or basic as can be,if the amps response improves,you have your problem solved,if not you can move on to another stage as you have discounted that "stage" as the problem.Gotta go one step at a time,and starting at the beginning is the best way

[The Captain]

I did redo the inputs, so now no. 1 is tighter and a tad louder sounding than no.2 on each channel (all have 1M checked) but with your point taken on board Ill strip them to one each tmrw. As to your help re my Q above Mr. Stokes that muddy dull sound is exactly what I have- but it sounds just like this on normal input/ normal vol, or with this vol at 0 and bright vol at 2ish.. so Im nearly convinced then that its the way its meant to be. I noticed that the tone is brightest at 9 tailing off again up to very dull again at max on normal channel, is this the norm too?

So, if you and others suggest the speaker should be ok although Im only getting little at best blatty, hard overdrive even with either vols (or both vols) high -then could the OT could be a weakness? I also read a certain better quality 5y3gt's blurb.. 'good for low headroom' etc: I didn't think the rectifier was determinant of clean headroom, rather having 2 12ax7s was the idea on this.

Thanks for the advice all- frustrating as this has been Im much happier knowing I can spiel with intelligent advice in reply. Im very reluctant to give up on this- heck I even made a flight case for it- so Ill crack on again tmrw.

[MWJB]

To check your speaker (& eliminate from our enquiries), pull the jack from the chassis (amp off of course) and put a 9v PP3 battery accross the jack plug terminals, one terminal to the barrell of the plug, the other to the tip. On connection you should hear a definite crack, if you're in doubt as to whether you hear anything, or you just get a quiet, dull "tick" then maybe your speaker is suspect BUT, as Stokes says, an Eminence 125 should be absolutely fine for your amp if in proper working condition.

If the OT was the weakness I would expect a fuzzy, "radio" like tone with no cleans whatsoever. This is not what you have been describing.

5Y3 - different brands may result in differing final voltages (more volts = more headroom) and a different envelope of the note (intensity of attack & decay). lots of factors contribute to clean headroom, rectifier is just one of them.

Don't give up.

[Bruce / Mission Amps]

As to your help re my Q above Mr. Stokes that muddy dull sound is exactly what I have- but it sounds just like this on normal input/ normal vol, or with this vol at 0 and bright vol at 2ish.. so Im nearly convinced then that its the way its meant to be. I noticed that the tone is brightest at 9 tailing off again up to very dull again at max on normal channel, is this the norm too? Assuming you are describing this condition accurately, nope, I still think something is not right.
However, the actual tone control is across the bright channel's volume pot so it's effectivness is limited, with respect to the normal channel volume pot.

The correct norm is this....the common cathode of both triodes of the 12AY7 allows the unused triode to be heard when plugged into the other channel and the two volume pots are wired in parallel, effecting each other's channel.

That unused channel, in a weird way, becomes a cathode driven preamp.
In other words, the common cathode resistor slightly modulates the unused channel's cathode by the signal from the one you are actually using.
Confusing?
Try this, plug into the bright channel and shut it's volume control down to zero.
Now, turn the normal channel's volume control up all the way and strum some chords (while plugged into the bright channel) and you will hear a low volume level, muddy tone that is about 1/4 the volume level of the actual channel you are plugged into, but there is very little treble response.

You can use this effect to alter the tone of the bright channel you are plugged into and this effect is part of the interactive volume controls peopole either love or hate.
In conjunction with the odd "cathode driven" preamp effect of the 12AY7 wiring, the two volume pots are also wired in parallel.
Signal is fed into the vol pots through their center lug, the wiper.
So when you turn the unused volume pot up while being plugged into the other channel, signal leaks over the top of the pot and you start loading down the "used" channel's signal path, shunting some of the audio to ground through the unused channel's volume control to it's 100nF coupling cap and over to the actual B+ supply filter cap, which is grounded.

[The Captain]

I think then I may be in the hate camp! Ive a better understanding of the pots now thanks Bruce. I'll look into that dual gang pot job I think (as per the s2 5e3); its also meant to help the quick ramping too- but this later- 1st I need to find out how/ if I can get any distortion with the useable bright channel. So
1. Im gonna ditch the plastic jacks for switchcrafts and install one each channel for the mo.
2. scratch my head again as to why barely any distortion/ check all wiring for 8th time.
3. ditch my mdf cab/ chipboard baffle (prototype) & make a pine cab/ ply baffle to help the general tone.
4. get this 5y3gt as it has 'good lower headroom' http://www.watfordvalves.com/product_detail.asp?id=94 ('sag' whats that?)
5. trim my beard.

here are my scribbled voltages:

Pin 3 (both pwr valves)= 389v/ 388v
Pin 4 screen= 341v
Pin 6 plate (preamp?)= 193v
Pin 1 plate= 155v
Power supply= 247v
Pin 6 (12ay7)= 126v
Pin 1= 121
Preamp cathodes= 2.04v, and 1.28v.

cheers, captain.

[MWJB]

Your lack of distortion isn't coming from the cab material.

Even the TAD 5Y3 should be giving you noticable break up, often 5E3 owners upgrade to 5V4 rectos (tighter still, more volts that you have) and the amps still grind plenty easy.

Sag is compression, a "squashy" sound, when you pick a note the internal resistances of the power supply & rectifier soften the initial attack, then as everything gets back up to spec, the note builds during the decay/sustain and the note appears to "bloom". With a 5Y3, std PT & filtering and cathode bias you should be getting this anyway.

Lower headroom means that it distorts at lower volume settings, even so, the 5Y3 that you have the amp should still be distorting.

Your not in the hate camp, we're all rooting for you. You've jumped in at the deep end and we all want to see you swim.

There must still be a fundamental wiring/component error, looking to change cabs, speakers, rectifiers etc is just muddying the water and drawing out the process. With the parts you have now a properly functioning 5E3 should be in there somewhere. The last thing you probably want to do is pull up the board, if your input jack swap doesn't reveal anything then this would be my next step.

[Colin]

Captain

Those voltages look in the right ball park and, as MWJB says, changing things like cab, rectifier etc won't solve your basic problem. I posted this on another of your threads to help with input jack wiring - so I hope I'm not butting in or anything.

Just scroll down slightly on this link to see an excellent description of input jack wiring (not mine!)

http://www.hoffmanamps.com/charts/CommonHookups.htm

Make sure you use the 4 x Switchcraft 12A (Tip/Switch/Sleeve) inputs.

Hope this helps

Colin

[The Captain]

(Partial) success! I stripped all the sockets out for one metal jack (2 lugger all I had) in the bright no.1.. now the tone/ response and sweetness came through better; before it sounded like a crap tranny amp- now a tube amp, responsive with sustain and a ringier fenderyness- so a good start. So then I popped another in the normal no.1.. bit better tone, but its still bass city/ unuseable- mixing vols bassed out things again. Gainwise (distortion) still not heard yet, BUT with an eq pedal level on max I can finally hear an overdriven tone: before this was only a slight 'blatty' break-up. Interestingly also, before as I measured powered down filter caps etc before a tweak they read 4-7V ish. Now the same points were ~0.5v could that tell a story?

Until I get some switchcrafts in at least I have a FULL ,very rich clean one input amp, and can see finally why blues players loved them. Tmrw and with much faffing Ill take the board up, and hopefully find a page 1 wiring mistake. Ive have grey whiskers in my beard now. thanks all- Captain.

[stokes]

Cap'n,as I have been saying,at least part of the problem was in the input wiring.I would advise just using one jack for the normal and one for the bright,as you are only going to use one at a time anyway.In both the 5E3's I have,I rarely use the normal input,with most guitars it is too bassy,only use it with a Telecaster.For the next step I would look over the volume/tone controls wiring.Dont use any EQ or other pedal,with a properly working amp,you wont need one,so using one while testing is only going to muddy the waters ,as MWJB has already pointed out.Your normal channel is going to be much bassier than your bright and as I said I find it undesireable with Humbuckers and only useful with something as shrill as a Tele.I dont fully understand what you are getting at with this description-"Interestingly also, before as I measured powered down filter caps etc before a tweak they read 4-7V ish. Now the same points were ~0.5v could that tell a story"?I am assuming you are saying you saw 4-7 volts at the main filter and now see .5v with the amp turned off.Is this ac volts or dc volts?Before what tweak?
If by being in the hate camp you are thinking that we have developed a hate for your problem,that is not the case at all,like MW says we are all rooting for you and I know for myself,it wil will be great to see you get this amp working,I know it is tough to decipher all the advice and pointers we are throwing at you,but stick with it,when you get this amp working I am sure you will be happy with it.I have yet to meet anyone who doesnt like this amp,the only complaint I have ever heard is that it doesnt have enough balls to cut thru a loud band.Once you get it working properly,we can start giving you ideas to tweak things like rectifiers and caps and speakers,but for now lets work with what you have and get it functioning right.Try the bright channel with both volumes turned up halfway,you should get some sweet overdrive,if not perhaps we have to look for some sort of oscillation,or a problem in the vol/tone circuit.

[The Captain]

Ive gone through all the replies here again, much fine info allround: today I checked wiring under board- all ok. The tone is better now with just one input each, still so full and bassy its impossible to turn up without a damn eq pedal's bass way down (the ONLY reason Im using the wretched thing). Almost taking a row of houses out (vol 8) to check for overdrive, there is some now :rolleyes: tho harsh & totally unuseable as its so venomously loud, and with that bass.. I built a 5e3 as it has 'great overdriven tones at lower volumes'; I hate any pedals too. So as a useable amp its clean only and hugely bassy the last 2 things I was after.. but I still dig it cos I made it! but this of course will wear off soon.

Ive checked absolutely everything so many times now/ changed caps valves, pots and even rewiring my SG. So it is definitely, unequivocally all as should be and there's now't else I can do :confused: my beard now has food bits in. Captain.

[Steve Conner]

If you've not owned an old non-master-volume style tube amp before, it could just be a matter of expectations. When people say the 5E3 Deluxe gives good overdriven tone at lower volumes, they probably mean lower relative to a plexi-fronted Marshall or whatever :eek: They don't mean that you can get distorted tone from the amp itself at levels suitable for practicing at home. Even my 3 watt Selmer with one EL84 has the neighbours banging on my door if I crank it at home. You may not appreciate the full mojo of your amp's cranked tone until you've played it "venomously loud" in a band situation.

Most newer amp designs have some sort of master volume-like arrangement on their dirty channel to let you drive the preamp tubes into reasonable sounding distortion without cranking up the power amp and bombing the whole area. Even Fender's own Hot Rod Deluxe reissue did that. It doesn't have the mojo of a cranked power amp, but it is damn useful, even in a band, for those times when you need to keep your stage volume under control. You can get the same effect with your 5E3 by using a tube screamer-type drive pedal or a power attenuator between amp and speaker. If you don't like the thought of a stomp box full of yucky silicon, I have seen schematics for a DIY drive pedal that uses only tubes.

Can you record some sound clips of the amp? I'm sure if you posted sound clips here, the 5E3 experts would be pretty quick to tell you if there was anything wrong with it. But you may just be suffering from non-MV culture shock. I remember my first non-MV amp, a Treble'N'Bass 50. It would go deafeningly loud before it even started sounding a bit dirty. I ended up modding one of the channels to add an extra gain stage, so it would break up at quieter levels, but still have the option to use it the way it was. I lent it to a friend who refuses to use the modded channel, and just abuses the stock one with a Tube Screamer.

[The Captain]

Of course naiive I as may have been, 'lower volume' can mean different things (relative to *?). I was shocked at how loud this 15w is- previously, and why I progressed to this build, I modded Epi Vjnrs. At 5w I had a rough assumption a 15w would be approx twice as loud (ish); & with 2 vols knowing they mixed together I assumed a sort of MV config- wrong on both counts!! It seems 4x as loud & the whole normal channel Ill never use as its bass is overwhelming. I did manage to produce a decent distortion adding a great MV (at approx the two 220ks in this 5e3 config) on the wee Vjr: I wonder therefore, and realise it may be sacriligeous :eek: whether a circuit such as this can be introduced.. (from a babe of a diy fender Vibrothingy- it seems to be Bruce's MV idea too) http://i102.photobucket.com/albums/m106/TheCaptain_02/pi-m-vol.jpg .. or even whether the normal channel can be hooked directly to t'other channel so effectively one channel with 2 vols? I'll also look into adding a whole new tone circuit with a bass pot- but next year or so.. I am enjoying the amp now at least thanks to help here, its (big!) clean tone has definite character- so a big cheers all. Captain.

[stokes]

Cap'n,if you are using the .1mf coupling caps,I would suggest changing them to .02mf.I went to the .047 and then settled on the .02's to brighten things up and lose some of the muddiness present with the .1's.The normal channel is still quite "bassy" compared to the bright,but is more usable with the .02's.I also found the 5V4 rectifier and boosting the main filter to 40uf or better (dont remember but I might have 80uf for the first and 40uf for the screen,but it is at least 40 & 40) helped reduce the flabbiness.The interactive volume controls dont work like a MV at all.Turning the unused volume to about 1/2 full will scoop the mids and somewhat quiet the volume overall,but nothing at all like a MV.

[The Captain]

Coupling caps being the two .1ufs twds rhs of board? if so I did that 1st up.. along with left preamp bypass 25uf/1.5k to .68/1.5k all three made no discernable difference at all (?) another reason i took the board out and other checks etc. Should I keep the two .1uf in middle of board (my RS big yellow chaps) at this value?

[stokes]

All 4 of the .1 caps are coupling caps.I changed them all.There is also an .02 cap from the plate of the stage preceding the PI input grid,I changed that to .01.The .68 bypass cap will cut mids from that stage and lower the gain of that stage too much,I would put the 25uf back,this value will boost all the frequencies your guitar is putting out and makes for better gain in that stage.In my opinion the .68 cap will cause too much of a cut in the gain of the stage which will adversely affect the gain and response of the following stages.

[The Captain]

Ill change all coupling caps to .1ufs Mr. Stokes

I have however a serious prob now- the amp keeps blowing fuses. Turn on, pilot light then goes out immediately. The only thing I did prior was to swap out plastic spkr jack for a metal one & wiring checked, all correct. Checked all over for obvious shorts- none. 4 fuses now tried all immediately pop. Im about to throw it in the river now.. what the heck can I do?

And it does exactly same with all tubes pulled.. so a blown PT now I assume!! nothing even touched as far as any filament wiring, checked continuity all along the filament wirings, all read above zero to gnd and same between them.. Im really going crackers now.

[stokes]

Did you ever make that 100watt light bulb current limiter?It will come in handy here.You can use it to diagnose the short without blowing a million fuses in the process.

[Steve Conner]

Don't throw it in the river, sell it to me! :D

[The Captain]

No I didn't make that limiter Mr.Stokes as MJWB got me up and running checkwise.. I wouldn't be 100% sure using it with HV PT wires without asking/ annoying you friendly lot with Qs again! Ive had a word with Weber (replied asap & with concern- helpful and friendly); he'll send another 'from a different supplier' tho another hefty import duty Ill have to pay.. seems like a common prob then with these Ts: Im surprised he sells them- it doesn't add to his good reputation. And who's to say the replacement won't blow? my confidence has tumbled badly now.. quite frankly Im very pissed off. I should have spent 3x on a Mojo but as many diyers I am on a budget somewhat. There are floods here in Warwickshire, so I can just hurl it out the window if need be..

Would this sort of thing have helped? It seems small enough to go in bttm of cab.. http://cgi.ebay.co.uk/R-F-I-Mains-Filter-250V-AC-50-60-Hz-15A_W0QQitemZ170064321061QQihZ007QQcategoryZ4673QQrdZ1QQ ssPageNameZWD1VQQcmdZViewItem

[Bruce / Mission Amps]

No that RFI filter wouldn't help your problem.
By the way, I'd be pissed off too because it seems like I've seen a few others with blown trannys over the last months.
I wonder if there is some underlining cause or just a coincidence.
Also, did you have this PT "protected" with a 1 amp fuse?

[stokes]

Do you know for sure your PT is blown?To check this disconnect all the secondaries and if the fuse blows with no secondary connections then it is most likely blown.But you also need to find out why it blew.The current limiter is a priceless piece of equipment for basic troubleshooting.It is cheap and easy to make and use.No problem or annoyance to me answering any questions you have Cap'n,and I am sure I speak for most others on this board,we were all in the same place you are right now at one time.For myself,there was no internet to go to,it was just books and if you were lucky enough to know someone in the business as I was,we were pretty much flying by the seat of our pants,so dont hesitate to ask,as you can see there are plenty of people here willing to help.Dont give up,you'll get there.

[The Captain]

Bruce I had a T2AL amp fuse, and a 3A in the mains plug. Mains plug one still ok after 4 or so tries, 2A blows even without tubes. All wiring not touched from when it worked for the 3 weeks or so too.

Mr. Stokes could you run that current limiter past me again, in say Homer Simpson language? The idea of making a box & another bits order put me off iirc; suffice to say as soon as I told Weber they offered a new PT straight up & from a 'different supplier' (a different batch of the same unit tho..??) so they seemed to think its dead Id say, rather than have me fart about checking each wire via emails. So Ill consider the limiter idea but have to thoughrally understand/ go over method 3x before I try.. & with a dangly beard my vision is now compromised too. Replies restore interest/ hope again, cheers Captain.

[stokes]

If you look at the thred titled "Help powering up" I even managed, with some help, to post the diagram.It is a very simple and inexpensive item to make and is extremely useful.If you intend to work on or build amps you will need it anyway.When you build it we can go over step by step how to use it.For now though if you just disconnect all your secondary leads.i.e. the main HV taps to your rectifier and your heater supply you can dismiss the PT as the problem.If the fuse doesnt blow with all the secondaries disconnected your PT is okay.The fact that your mains fuse is not blowing is making me think it is not your PT.The fuse that is blowing I assume is on your B+?If that is the case and it blows with the tubes removed that would indicate a problem with your filter caps.Why do you have a 3amp fuse in the main?Here in the states we would use a 2amp and I think in Eur.it would only require a 1amp,no?

[The Captain]

I know you did Mr.Stokes appreciated so it was- I did read it numerous x too: although its just a few bits I just can't visualise the thing- is yours housed in a case? so then this must be earthed, routed, drilled & a switch/ fuse too etc? also our uk wires are brown L, blue N and green E; yours different iirc; 'female ac outlet' slightly odd for a brit, do you mean a mains wall-plug socket or a 'kettle' type input? ..as you see uncertainty didn't seem fitting for the job. If you had a pic/ photo it'd answer these queries I reckon.. cheers capt

Edit- ok (after hours of head-scratching) is this the idea: basically a box with two mains-type plug sockets and a lead out the back to mains? Amp plugs into one socket, a ..normal household lamp(?).. plugs into other. (If so every time I saw the diagram/ info I've been trying to figure out how a 'light' attatches to the box, assuming it was was a bulb & its socket holder, & an extra socket all somehow mounted in/ or to the top of a box -until just now!) maybe Im still not getting it though.. crikey I think I need a holiday, or an institution..

[stokes]

What you see in the diagram is what it is,just adapt it to your 3 wire set up,one ground,one hot and one neutral.What I used was a double wall type outlet and box,which is standard here in the States.Since the wall outlets are wired in parallel,I just snipped the connection between the two outlets so I now have two independent outlets and rewired them in series.Now to use it for a test I plug the plug you see in the diagram into the wall,the amp under test goes in one of the rewired outlets and a desk lamp with a 100watt bulb gets plugged into the other rewired outlet.You can also use a single outlet and wire a bulb socket in series with it,in other words the bulb socket would take the place of one of the rewired outlets,just plug into the wall and plug the amp into the socket.Now for a quick example of a test.If the bulb stays lit brightly there is a short,if the bulb dims considerably there is no short.Lets say you get a bright bulb,you have a short,you pull one power tube the light stays bright,pull the next,if the bulb dims you have found the problem it is in the second tube or its related circuit.If it stays bright after pulling all the tubes you start disconnecting your filter caps till you find the short.It will save a lot of fuses and the amp can be left on while you poke around to find the short as opposed to having a flash and blowing the fuse.

[The Captain]

Hey Im with you now Mr. Stokes, muchos muchos..
Could I make this as a plywood box do you think? (our uk mains leads have green earth wires Id usually terminate to metal chassis)- if so would wood suffice for terminating.. I mean on the face it seems a bit odd to me, but'd save me arsing about for metal enclosures and faff cutting/ drilling one etc.

[stokes]

I dont see why a wooden enclosure wouldnt work.Dont they sell an outlet box in Britain?Here it is very easy to get a wall outlet box at a home improvement type store,and the outlets themselves are sold as a pair that fit into a "standard" size box.If making a wood box is easier,it will suffice.Our "earth" wire is green as well,but in this case there is no need to connect it to the box it connects to the "third"prong of each outlet,as you can see in the diagram.

[The Captain]

Ah yes of course.. ok Ill pop off to Homebase and see if they do outlet box things. I'll add a photo of it once made to be sure alls ok and go from there.

[stokes]

Homebase?Here it is called Home Depot.If like here the outlets are sold in pairs they are connected somehow in parallel,so you will have to find how they are connected and seperate them so as to wire in series.The ones here are connected at the screw terminals on the side by a solid plate type thing,just snip it on both sides, a quick continuity check with the ohmmeter will tell you they are seperated.

[The Captain]

Well call me old-fashioned, but I knocked this up in 10 mins. From an old 4 way extension, Ive bent/ stripped out the brass links that were paralled for 4 to just 2 now in series.. I think.
The mains pins far right are top gnd, middle (brown) L, and bttm (blue) N. (pic looks like mains gnd connects the top and middle pins! -not so, brown Live tucked under for pin 2).

So Ive got the normal Live pin of 1st outlet now connected to the (normally) Neutral pin of 2nd outlet, and the N pin of first to the normally L of the second; the gnd lugs just kept as was really.. Id really best check this first- thanks Capt.

http://i102.photobucket.com/albums/m106/TheCaptain_02/Picture275.jpg

[Steve Conner]

It should only take about 10 minutes to make. Here is the UK version of the instructions:

All you need is a so-called suicide lead (13 amp plug to three bare wires) plus two 13 amp sockets (either the wall kind or the trailing socket kind) some spare wire and a table lamp. If you're using wall sockets, highly recommended is some kind of housing for them, so you don't have exposed live terminals. The lamp should have an ordinary 60 or 100 watt light bulb, as recommended by other posters, and nothing fancy like a dimmer switch or touch switch.

Connect the earth of your suicide lead to the earths of both 13 amp sockets.
Connect the live of the suicide lead to the live of socket no.1.
Connect the neutral of socket no.1. to the live of socket no.2.
Connect the neutral of socket no.2. to the neutral of the suicide lead.
Plug table lamp into socket no.1. and faulty amp into socket no.2.
Turn table lamp on if it has a switch.
If you used sockets with switches, don't forget to turn them both on.
Plug the suicide lead into the mains and turn it on.
You can now try turning the amp on and following the troubleshooting instructions that Stokes and others have given.

Remember to treat 240V UK mains with twice as much respect as Americans have for their weedy 120V. This device will stop your components from frying, but it does not give any extra protection against electric shock compared to plugging the amp straight into the mains.

[Steve Conner]

I just noticed your modified 4 way extension, that looks like it will do the trick fine :D

[The Captain]

Ah great thanks Steve: I just need to 2x check my mains leads are ok to the outlets -both joining at the 1st outlet as it were- or should one join here and t'other at 2nd outlet? ( the L and N both interchanging causing slight gnashing of teeth here admittedly).. don't wish to cock this up.

[The Captain]

Im still a bit reticent so it makes sense to double-check my limiter/ application; its just the N from lead, should it join as so in my pic or at the '2nd' (left one in my pic) outlet's previously L now N, or does it matter not? But assuming ok, if I were to then..

Plug both amp and lit lamp in, am I turning amp on with all tubes in and not applying the standby switch?

To rule out the PT, am I looking for either the lamp staying lit and therefore the pilot light going off/ 2A fuse popping again, or the lamp not lighting at all..? I guess I'll have to stock up on 2A fuses for this, or am I missing a trick..

Cheers Captain.

[stokes]

Cap'n,when using the current limiter you wont blow the fuse,even with a dead short in the amp somewhere.When you turn the amp on,still in standby if the bulb glows full bright you have a short in the heater supply.Once you flip the amp out of standby,the bulb will glow bright for a few seconds till the caps charge up,then it will dim significantly,if it doesnt,you have a short.So you see,with the limiter,if you have a short the fuse doesnt blow,the bulb stays lit bright.Do you have a known to be good amp?If so plug this in in your limiter so you can see how much the bulb will dim in a properly working amp.To check your PT,you must disconnect all the secondaries,as I explained earlier,now with nothing in the circuit but the PT if the fuse blows or the bulb stays lit bright you have a problem in your PT.Earlier you said the mains fuse didnt blow,but the fuse in the B+ rail was blowing,no?I believe you said it blows with no tubes,that leads me to believe the problem is in your filter caps and not your PT.To use the limiter,you would start with all the tubes in,if the light indicates a short,while the amp is on,you start pulling your power tubes one at a time and see if the bulb dims,if it dims when you pull,lets say the second power tube,the problem is associated with that tube or its related circuit.If the bulb doesnt dim then the short is somewhere else,so the next step would be to disconnect the filter caps one at a time till you find a short.If it is not the filter caps your next step would be the rectifier,when you pull the rectifier if the bulb stays bright then the PT is your likely culprit.I am trying to make these explanations as simple as I can,but I realize trying to simplify things can have the opposite effect,as well as the fact that I am probably throwing a lot of stuff at you all at one time,so if you have questions just keep asking.

[The Captain]

Thanks there again; I think I get the basics, ie idea behind the system, and realise such a simple thing can be very benneficial.. Im a bit bombarded at the mo with applying (I know it possibly can't be explained any more simply).. but 'page 1' bits Im not clear still. You say amp on standby.. Im still unsure as to which amp switch starts the test as it were, and also whether if as I do, wish to just check the PT for now if I start with PT wires as is (all connected as per finished amp) or disconnect the 2ndaries as you suggest above.. surely I cant tube check once 2ndaries disconnected-? If I am disconnecting them, should I seal ends for safety too..
Having a Twin yonks ago I had to be reminded re. start-up switch routine again, and was told thus: Switch next to pilot lamp on first, allow to warm up, then apply standby to on. Ive just read on at least 2 tube amp general sites that the complete opposite is correct.. I think im going barking mad! and your help above re standby has caused slight confusion too, as I'd assumed as my fuses blew with standby not even applied yet that these tests were done similarly without standby mode innitiated yet.. Im gettin me knickers in a twist Mr. Stokes!

[stokes]

When powering the amp up,regardless of when testing or for normal use the power switch gets turned on first,the pilot light will come on,after a couple of minutes turn the standby switch on.To do it in reverse is pointless.I'll run thru the test procedure again,for now,lets forget about disconnecting the PT secondaries.With the amp and the lamp plugged in,turn the mains power switch on,pilot light will light as well as the 100watt bulb,the bulb should be dim,if the bulb is full brightness,there is a short in the heater supply or the PT.Next turn the standby switch to the play position,if the bulb is bright there is a short somewhere.Remove one power tube,if the bulb dims,the short is in the tube or the related circuit,if the bulb stays bright remove the second power tube,if it is still bright go to the preamp tubes,if after all the tubes are pulled the bulb is still bright pull the rectifier,if the bulb is still bright,you will disconnect the PT secondaries,and if the bulb is still bright now the problem is your PT.If you strongly suspect the PT you can just jump to the last step and disconnect the PT and test.

[The Captain]

Aha- now Im back on board: total confusion with standby switch's ON=open contacts & OFF=closed.. contrary to every other **ng switch it seems.. so I'll refer to it now as open and closed (play).

Ok that makes more sense, Im seeing if an obvious prob lies along any other paths before the PT so leaving it hooked up for now, got that. So assuming the heaters are ok with the lamp dim, & I close standby and lamp is bright.. I pull the first 6v6 -but it'll be too hot to handle no? (its difficult to tug out even cold) -and WTF if it breaks?! surely that's lethal, or do you turn amp off before and between tube pulls?

[The Captain]

Ok 1st test done am- with lamp on and new fuse in amp I turned on- no dimming of light and the fuse blew/ pilot light off immediately..?

[stokes]

The fuse blew with the current limiter in series with the amp?Is the limiter bulb lit up before you switch the amp on?Sounds like something in the limiter is not right,the fuse should not blow with the current limiter hooked up correctly.

[The Captain]

Seems so..? another pic of my limiter to 2x check: http://i102.photobucket.com/albums/m...Picture275.jpg Capt.

[TD_Madden]

sounds like the lightbulb is in parallel instead of in series with the power cord....

[The Captain]

Maybe that link not work here it is..

[stokes]

From the picture it looks like you have it wired wrong.Look at the diagram I sent you again.The yellow wire from the mains plug should connect to the outlet lug it is connected to ONLY,disconnect the long wire you have to the outlet on the far left.The blue wire from the plug shhould be connected to the outlet lug at the far left ONLY,then the two middle outlet lugs are connected together.

[The Captain]

Trouble is my pic suggests my wiring is not as is, as wires are tucked away, or go past terminals not connected: The yellow wire from mains must be gnd you refer to? and so must connect both outlets gnd pins.. confused now again. I have joining terminal block far Rhs..

Green gnd from mains lead to top terminal
Live brown to the middle terminal
Neutral to the bttm terminal.

The brass links Ive rebent to rejig it.

[The Captain]

I think Ive seen my schoolboy error.. will rejig, repost a pic asap and remove my above pic (!). Captain

[The Captain]

Right then- rewired and 1st test done: I turned on amp and light bulb shines full, and with no pilot light on amp..?

[stokes]

Something still aint right.Assuming the top lugs in your picture are the grounds and the two pairs at the bottom are the "live" connections,one "live"wire from the plug to the closest outlet lug,one live wire from the plug to the outlet lug at the furthest left,then the two middle lugs connected together.We'll get there.

[The Captain]

Here it is the rewired: brown L wire to pin Rhs, blue/ red N wire to pin Lhs (extended wire at bttm), central pins joined and not connected to any wire, earth wire joins both top pins. I can't surely have this wrong still?

This is how it was wired for the last test (post #11, above).

Im baffled by this: "The yellow wire from the mains plug should connect to the outlet lug it is connected to ONLY".. the only yellow must be the yllw/ grn earth, and your diagram shows it connects both pins-? Both sockets must connect to earth- Im so confused again ..

http://i102.photobucket.com/albums/m106/TheCaptain_02/Picture277.jpg

[stokes]

In the first picture it looked like the yellow wire was the "live" wire,not the ground,the brown was not seen.This shot I can see the yellow is ground and should only be connected to the ground of each outlet.I am not familiar with the European 220v color codes,but it appears to be okay,if you are sure the yellow is the ground.When you did the last test are you sure you had a good fuse?Do you have a 100watt bulb in the mix?Could it be that with the 220v mains you need a different watts bulb?Maybe Steve can answer that I know with the 120v mains we use a 100watt,perhaps it should be different with your 220v supply.With this apparatus the fuse should not blow.Earlier you said the mains fuse was not blowing but some other 2a fuse was,you also said you had a 3amp fuse on your main,is that right?I know I asked but I never got clarification.Is that 2a fuse in your B+ rail?And why are you using a 3amp in the main.For a 5E3 here we use a 2amp,you should be using a 1amp with your 220v main.

[The Captain]

I had the 100w light switched to on but not lit (in Uk 100w is brightest we'd put in a std lamp) and noticed when turning on amp the 100w lit bright, without amp light. It didn't blow a fuse this time though.. should the 100w be lit before amp turned on? If so I must still have something not hooked up right.

As to mains plug fuse, yes I had a 3A there when amp died (it stayed put but the amps T2AL popped even with no tubes); a 3A mains plug fuse was suggested by the Uk supplier whom I got the amp fuseholder/ T2AL sloblow from -Im fairly sure- or it could have been just my daftness. *It makes sense I guess in hindsight to have had a 1A in the mains plug before the T2AL in amp, and perhaps then I may not be looking at a died 5e3 if the 1A would have popped before any nasties got to amp? Anyway it shouldn't be dead it was not a month old.. and I still need to find out why, and narrow search to exactly what if possible.

*is that a dead cert, or not neccessarily so? Thanks alot, Captain.

[stokes]

Where exactly is that T2AL you refer to?If you had a 3amp fuse where a 1amp should be,then yes, you may have fried something like the PT.Getting back to the limiter.The light switch should be on,but the 100watt bulb should come on only when the amp is switched on,but the pilot light on the amp should come on,indicating the amp is on as well.Check to see if you have voltages in the amp,maybe your pilot light blew?When plugged into the limiter,the volts in the amp will be lower than normal.I am beginning to think you had a short in your B+ and since you had a 3amp fuse you may have fried your PT.When the 1amp would have blown,you let 3x's that much current go thru your PT.Disconnect the secondaries to the rectifier and the heaters and see if it blows a 1amp mains fuse.Tell me where that T2AL fuse is.

[The Captain]

Thanks Mr. Stokes- I can verify I have 2 fuses..

1. mains plug fuse at 3A- will change to 1A (if applicable for Uk?)
2. amp fuse at T2AL as per std 5E3 layout, ie in series before AC switch.

So to recap I did test using correctly (95% certain now) wired limiter:
turning on amp lit bulb bright only with no pilot light on amp, neither pilot bulb or T2AL amp fuse popped..?

[stokes]

Capn,I'm still not clear on that T2AL fuse.Is this something related to the U.K. wiring?The standard 5E3 layout here has one fuse on the AC mains line opposite the switch,and is 2amp.Take a voltage check inside the amp when it is connected to the limiter,if the pilot light is not lit and the bulb and fuses are good,you should have power inside the amp.It is possible the PT is totaly shot and you have no power at all,in this case the bulb will light full brightness.Do you have an ETA on the new PT?

[The Captain]

Im con-fused as to your query re my T2AL: its the std fuse on the main AC line in the amp as you say above/ as my 'no.2' previous post; there's no way we can get muddled if just one fuse in a 5E3 can there? it sits between the 2 switches in a fuseholder; a small glass fuse with metal ends about 15mm long and a filament visible through glass.

Is your Q specifically why its a T2AL as opposed to a 2A??

As to new PT I expect any day.. but unless I can find out why this one blew there's no point fitting a similar PT as it'll just blow again. So sell it as new/ spkr/ OT other bits etc and recoup as much as I can? seems a shame after such a huge effort.. I grately appreciate the help of course, and WILL get at least one limiter test done successfully though. Cheers Capn

[The Captain]

Realising having 2 bulbs (a pilot lightbulb and a 100w lightbulb) may be adding confusion:

Test was so:

1. A 100wLightbulb (standard desklamp) and the amp are plugged in to 2 sockets on a limiter (100wLB switched to 'on' but does not light yet).
2. When amp is turned on 100wLB lights & stays at full brightness- but the amp's pilot light does not light.
3. When amp is turned off this turns off 100wLB.

If anyone has any idea what this test may signify/ mean, or what could be done next or any idea (bar throwing a very large distance) why a 5E3 keeps blowing fuses Id be grateful! It'd also save Mr. Stokes's sanity I think. Captain.

[RickyD]

1. Pilot light bulb burned out. Check filament continuity to confirm.

OR

2. Pilot light bulb is not in the circuit. Check voltage at socket and back track to the fault.

-Rick

[The Captain]

The pilot bulb filament has continuity, and is sitting in its holder. If the pilot bulb had burnt surely the 100wLB wouldn't light as there'd be a break in the circuit? ie circuit being into the amp through 100w light and out?

[stokes]

Thanks Mr. Stokes- I can verify I have 2 fuses..

1. mains plug fuse at 3A- will change to 1A (if applicable for Uk?)
2. amp fuse at T2AL as per std 5E3 layout, ie in series before AC switch.

So to recap I did test using correctly (95% certain now) wired limiter:
turning on amp lit bulb bright only with no pilot light on amp, neither pilot bulb or T2AL amp fuse popped..?

Here you are refrering to two fuses.Are they both in the amp?Or is one in the current limiter?The fuse in the amp should be 1amp,not the one in the current limiter,the current limiter doesnt need a fuse.

[stokes]

Did you check for voltage in the amp with the limiter hooked up?It sounds like you arent getting power to the amp at all.If the current limiter is wired properly you wont blow the new PT,that is the point of using the limiter,so you can diagnose the amp without blowing the fuse or anything else in the amp.

[The Captain]

Yes 2 fuses: one in amp (2A sloblo "T2AL" in series before amp's AC switch as on the 5E3 layouts) the other in amp's mainsplug for the wall (3A will change to 1A if applicable to Uk). The limiter has one 13A in its mainsplug. We always have fuses in our plugs here without there'd be a hole in it- perhaps confusion lies here?

Im yet to check any voltage in amp- will do this ev: should I leave tubes in, and where exactly is best spot to place MM red probe (black on chassis obviously), assuming I am applying only amp's AC switch and not its standby?

Sorry for any confusion I may have flung about.. muchos, Captain.

[stokes]

"2A sloblo "T2AL" in series before amp's AC switch as on the 5E3 layouts".This is the one that should be 1amp,it is 2amp here.The other one I have never seen and is the cause of the confusion,not used in this country.
The first voltage check will be to make sure the limiter is working right,so you will check that you have voltage at the PT primary to wall connection.Put your meter on AC and check this.If there is voltage there then we know the limiter is okay.Now check if you have filament voltage,if you have and the pilot lamp is not lit then the pilot bulb is burnt out.

[The Captain]

something serious ain't right- I attatch MM set to AC with black on chassis and red just after amp fuse (in amp, in fuseholder as per 5E3 layouts) to check for voltage in amp. I plug 100w into limiter (Lhs socket in pic below) switched to on, unlit and ready. When I plug amp into limiter (Rhs in pic below- amp AC switch defo off too)... all house loses power/ tripped; I think Ive lost my sanity this is farcical! my limiter again: http://i102.photobucket.com/albums/m106/TheCaptain_02/Picture277.jpg

Middle pins joined.
Rhs pin to lead's Live (brown).
Lhs pin to lead's Neutral (blue/ red in pic at bttm).
Top pins joined and to lead's Earth.

Neither; rhs pin/ lhs pin/ joined central pins/ joined earth pins.. have any contact or continuity with one another. (Apart from obviously the joined pins to each other).

[stokes]

I dont see how it can cause the fuse to blow,but the MM leads should not be connected to ground to check AC volts,they should be connected to the 2 AC components i.e. each side of the PT primary leads.The limiter looks to be okay in the picture,but maybe there is something about the mains supply in the U.K I am not familiar with,maybe Steve can see something here that I dont see.

[The Captain]

Maybe not having MM leads right caused it? though Im completely at sea with fuse values now; Ive 3 plugs' fuses using the limiter & amps fuse which you say should be 1A now -although I was recommended 2A sloblo by MJWB for Uk and was working fine for the 2 weeks- let alone what on earth Im meant to have now in the amp's plug for the Uk).

Can any UK users tell me exactly what fuse values to use for the amp, and for its mainsplug?

Mr. Stokes can you clarify this: "connect to the 2 AC components i.e. each side of the PT primary leads" or exactly where do I put the 2 MM probes? I can't understand 'each side' bit, as the primaries to me are all on one side, the secondaries t'other and as I've always read amp voltages with black MM probe to chassis before-? thanks.

[stokes]

When measuring dc voltages the black gets connected to chassis or ground.When checking ac voltages the probes get connected to both ac components,for instance the PT has two primary leads,both black right?Black probe goes to one of the leads,red probe to the other.Another example,on your power tube you have ac heaters connected to pin 2 and pin 7.Put one probe on pin 2 and the other on pin 7.
As for the fuse value confusion,the fuse in the amp that you see in the schematic is listed as a 2amp.That is for USA mains supply which is 120v.In the U.K. you have 220v mains supply so the fuse value for the U.K. would be 1 amp.The one you describe in the "plug" that is common to the U.K. and doesnt exist in the USA can be 3amp,or 2amp,as long as it is rated higher than the 1 amp in the amp.By having a 2 amp where you should have a 1 amp allows twice the current to hit the amp before the fuse blows,even tho the PT wont fry on the spot, over a time the PT is getting twice the current than it is designed for due to a short or possibly just a leaky cap in the amp,after a while the heat from the excess current causes the PT to slowly burn till it shorts out.I suspect this is what happened to you,but we still dont know for sure that your PT is fried.So here is what I want you to do,disconnect the PT secondaries,that is the heater supply and the 2 high volt (red?) to the rectifier.Put a 1amp slo-blo in the amp itself,where you had the 2amp.Forget the current limiter for the moment,plug the amp in and turn it on,if the fuse doesnt blow turn the standby switch to on.If the fuse doesnt blow your PT is okay,but I suspect it will blow on the initial start up before the standby is switched,in which case the PT is shot and we will start again when you get the new PT.I have a feeling your PT's primary is shorted and that is why the house breaker blew.

[The Captain]

Ah yes of course measuring AC across things as on heaters for 1st time checks.. muppet! not sure if any difference, but my primaries are grey 240v joining AC switch and black '0' joining mains lead neutral. (*incidentally is a 1A sloblo still correct for 240v? 220v before you may have assumed ours to be). Id better not cock this up again.. so to 2x check:

Im disconnecting secondaries: 2 HV reds from PT to recto, (*2 yellows from PT to recto too?), 2 greens from PT to pilot lamp. Im installing a T1AL in amp, and a 3A in amp's mainsplug (into wall). Should I be sealing all the bare ends to be safe, or just keeping an eye they dont touch anything or each other? will try this later, captain.

[Steve Conner]

OK, to clarify things:

In the UK, every mains plug (the plug is what we call the part on the end of the line cord that fits into a wall outlet) has a fuse integrated into it. This is the mysterious extra fuse that has been puzzling you, Stokes. The fuses are a standard type that can be bought from any hardware store and come in 2A, 3A, 5A and 13A. 2A or 3A are most appropriate for guitar amps.

As for the fuse in the amp itself, 1A should be fine, 2A is a tad high for 240V, like Stokes has been saying. I've had a 1A fuse in my main guitar amp for years, and it's a 60 watt unit with 6550s. It only blew once, and that was when I dropped a screwdriver in the chassis while tweaking it and shorted the B+ to ground :eek:

If your lights all went out, well, you probably have a RCD (what the Americans call a GFI) in your house's fuse box, and you somehow allowed current to leak from live to earth and tripped it. When measuring on the mains side of the PT, you should put the black prod on neutral, not earth.

If you're going to disconnect the PT, yes, wrap the loose wires sticking out of it in insulating tape.

[stokes]

Wasnt sure if it was 220 or 240 over there but either way it should be 1amp.Same rule,double the voltage halve the amps.You dont have to remove the yellow 5v heaters to the rectifier if you pull the tube.In fact if you pull all the tubes it is not necessary to remove the green 6.3 leads either just take out the pilot bulb as well.This check is going to tell us if your PT is shorted.With all the leads disconnected the only thing you are plugging into the wall outlet is the PT,so if it blows,the PT is problematic.The only thing I can imagine would cause the limiter to act as you described where the 100watt glows full and the pilot light on the amp doesnt come on is the PT primary is shorted,so we will sacrifice a 1amp fuse and not use the current limiter for this.

[The Captain]

3rd check finally done Mr. Stokes as you said; PT 2ndary wires unhooked, 1A amp fuse, no tubes in.... 1A fuse blew immediately.

My last Q really then is whether this may have damaged any other part of the circuit ie, OT? And of course if there is much I can do to prevent this PT dying happening again, assuming a similar PT is on its way(?).. or is it just bad luck and Im peeing in the wind now with any other checks/ diagnosis/ assumptions I can make.

[stokes]

Okay,now we know for sure the PT is fried.I am inclined to think something in the amp caused the PT to go south,shorted or leaky filter caps are a prime suspect.Assuming the current limiter is working correctly,and you use the proper fuse value,1amp as opposed to the 2amp you had there,you wont fry the new PT while using the current limiter.My theory is that you had a short somewhere and using the 2amp fuse caused too much current to flow thru the PT without blowing the fuse and killed the PT.Since the pilot light didnt light with the limiter,I suspect you fried the PT's primary,this of course is only theory,since from where I sit,I cannot see everything in the amp.When the new PT arrives we will go thru some tests with the limiter,and track down the short.This is why the current limiter is such a valuable piece of test equipment,if you had made one back when you first wanted help firing the amp up,we would have found the short before any damage could be done,at least it only cost some time and headaches,and you arent paying for a new PT.There is always the possibility that it was just a bad PT to begin with.

[The Captain]

Im inclined to think it was just a bad PT rather than any other part of circuit or leaky cap- but as Im apprehensive about the new PT dying I'll re-read your info and get sorted for new start up checks with the limiter..

Q- assuming PT here asap, shall I connect it up as normal ie all 2ndaries? I wont fire it up yet of course. Thanks Capt.

[stokes]

Sure,it could have been a faulty PT to begin with,as I said my theories are just that,theories.Its kind of a hell of a time to ask,but you are sure you are using a PT for your 240v and not an American PT for 120v's,right?When you get the new one wire it up as normal and fire it up with no tubes in it first,then shut it down,install the rectifer and fire it up again,shut it down and install the power tubes and fire it up again.If the light doesnt burn bright on any of these steps,install the preamp tubes and fire it up again,If the 100watt bulb burns bright after any step described above,the short is related to that part of the circuit.If you are lucky it was just a bad PT to begin with,lets keep our fingers crossed.

[The Captain]

New PT wired up (240v primary), 1A fuse, limiter, 100w lamp for testing:

1. No tubes/ then all tubes with just AC applied= significantly dim 100w lamp (not FROM 'bright' or even half bright though).
2. All tubes, AC + standby(closed)= 'half' lit lamp, not dimming though..
3. AC + standby(closed) no preamp tubes= half lit lamp as above..
4. As above with both output tubes taken out (one by one)= still half lit lamp..
5. So then as above with just recto tube= significantly dim FROM half lit lamp on innitial powering..

No fuses went/ pilot light lit :o
Once powered down and checking filter caps after 10mins before poking about (for safe voltages check) I noticed all 3 filter caps still at ~200v :eek: - after 30 mins still at 100v.. maybe this tells a tale? (apart from bloody good job I checked!), but Im completely lost at sea on all bar 5. of these results, as I expected any dim lamp to 1st be bright. :confused:

[The Captain]

Just tested:

Recto + preamp tubes (no power tubes) AC & stdby closed= significantly dim 100w FROM half bright on powering up..

so Ive nailed it to the power tubes or related circuits? Im still not happy about the bulb not dimming from a nrmally bright 100w bulb (its as if it dims right down from say a ~20w bulb; as the 5e3 is ~20w too maybe correllated/ this IS correctly bright?). Any help much appreciated, Capt.

[stokes]

Way too much info there.Lets keep this simple.Put all the tubes in the amp,turn the AC mains on,if the light doesnt glow bright,and I suspect it wont,turn the standby switch to the play position,at this point the bulb may glow bright for a second as the caps charge up and then dim.If this happens you are good and the culprit was the old PT.If, when you switch the standby to on,the bulb glows full you have a short.Pull the power tubes one at a time.If the bulb dims when you pull the first tube,put it back and pull the second and see if the bulb dims as well,if so pull the other one and the bulb will dim further.90% of the time any short will be in the power supply.I wouldnt worry about the caps holding a charge,that is what they are supposed to do,I am going to guess that when you saw the 100v's there were no tubes in the amp,but anyway it is a good sign-if any of your filter caps were "leaky" or "shorted" you would see no volts on those caps as soon as you shut it down as the volts would drain imediately thru the "leak" or "short".I'm sorry but I just dont see in your last two posts where you describe the limiter as glowing full,indicating a short,so re-do the check as I just described.I could be wrong,but I think you are expecting that the light should glow bright and then dim every time,it will only glow bright for a split second when the caps are first hit with the dc.Tests performed immediately after may not produce the bright light again as the caps will still have a small charge.

[The Captain]

Apologies for too much info Mr. Stokes! (I do try and keep concise- badly obviously).

**Results with both switches flipped: All tubes in= bright lamp. Pull either power tubes or both= lamp dims**

My query is the lamp when bright. I expected to see a fully shining 100w. I see only 1/4 of this shine when bright (as if the bulb was say a ~20watter). It significantly drops from this when dim. (If my explanation here is not clear, imagine a rotating dimmer switch: my bright is ONLY at 4 on the dial, my dim is 1 on the dial. Id assumed my bright would be max 10/ dim to be 1). Hopefully I can dismiss this concern/ these are normal findings..

Thanks Captain.

[Steve Conner]

Hmm, sounds like your old PT was the problem, then. The results with the new PT sound like the amp is working correctly now. The lamp won't light fully with all the tubes in: it only lights fully if the amp is shorted out somehow.

If you're worried that the amp is still faulty and will kill the new transformer, you could try taking the old dead transformer to someone who can examine it and tell you how it died. For instance, if the heater winding is burnt out, maybe you need to check your heater wiring for shorts, etc.

[stokes]

Trying to describe exactly what brightness levels you will see is difficult to do.I get different brightness levels from different amps.I just checked a 5E3 I have on the bench,which I know has no shorts and I actually get no light at all,not even dim,whereas if I plug my MKII Boogie,which is also working right I get some light,but not what I would describe as bright.I cant positively say your amp has no shorts based on what you are saying,as Steve does,I also cant say Steve is wrong,as I cant see the light levels you are describing.If the light gets considerably brighter than it is with the mains on and the standby swith off when you flip the standby to on,I have to think there is a short somewhere.After warm-up when the standby is flipped to the on position,the light will get a small bit brighter,and possibly get very bright and settle down to about the same level as when it is in standby mode.If you are unable to make a definitive call,I would say the fact that you now have a 1amp fuse in the proper position will protect the PT if you plug it directly to the main outlet (no limiter),the fuse will blow if there is a problem.You said in an earlier post that you had 100v on the filter caps half an hour after turning it off.This is a good indication that the caps are okay,as I explained earlier.Other considerations pertaining to the power tubes would be:the tubes themselves,cathode resistor and bypass cap i.e. the cap could be shorted or the bias resistor could be shorted or too small to bias the tubes properly,and it is simply a case of the tubes being biased too hot.

[The Captain]

Ah ok- if it was definitively a usually bright 100w bulb I must see, then I'd have concerns. As there's not it seems Im a bit lost again.. BUT although I was 98% sure at this point I had a short (as only when both 6v6s pulled did the lamp dim) still hooked up to limiter, I warily just plugged the f*&%r up...

ITS ALIVE! Ive my amp back it seems GREAT! unless I still may have a short- surely not if it works though? Im inclined to use the amp with the limiter/100w for a 'safety barrier' now, but only if there is any sense in the idea-? Is there anything else I need check too to be sure? I so hope this PT wont pop again or it WILL go out the window for sure! :)

[stokes]

The fuse would blow if there was a dead short.If it is a case of something drawing too much current,but not enough to blow the fuse,you will notice the PT getting very hot when you use the amp.We are not talking about it getting slightly warm,that is okay,but if it gets very hot.I would not recomend playing the amp while connected to the limiter,it is for diagnosing only,use it plugged in normally and put your hand on the PT from time to time.If it doesnt get very hot after about 20-30 minutes,you should be okay.I would check the current draw on the power tubes to be sure they are okay.I would say 22 to 28ma's would be okay,depending on your plate volts,if they are any higher you may want to tweak the cathode resistor.

[The Captain]

I think Im there Mr. Stokes (at long last, 110 posts!)- so a VERY big thanks for your help and patience on this thread. Hopefully I wont be along with any more gremlins soon. Lastly, could you just remind me how to check power tube current? the chassis seems normally warm, but Id like to do as many checks to minimise any chance of this PT popping.

Cheers, Captain.

[stokes]

To check the current draw you can use a milliammeter,put the red lead on the CT of your OT and the black lead on the plate of one power tube,this shunts the current from the OT to your meter.Another way would be to check the voltage drop across the cathode resistor and do the math.
When you say the "chassis seems normally warm" I assume you mean the PT seems normally warm,if not check the PT not the chassis for excess heat.

[The Captain]

I'll try that Ma MM check tmrw Mr. Stokes. I gave the beastie a good run today. PT seems to remain normally warm, & looks to be a bit better quality so fingers crossed.. Ive a Jensen C12N in now which suits way better (cheers MJWB): that bassed-out sound gone.. great. I found the legendary overdrive too, albeit at vols I can't use unfortunately but NOW I see what the fuss is about! I kept playing it for hours (clean only as I got a complaint from 500yds away with it overdriven! but the clean is very sweet). So thanks for spurring me on folks; it been worth all the effort. Captain

[stokes]

Glad to hear you are finally happy with the sound and performance of your amp.I have to wonder if the problem with the sound was the bad PT all along.

[The Captain]

I cant say for sure as I was eager to replace skr with the C12N at same time- but it sounds much better, perhaps a bit better quality PT? Id like to add a gain footswitch (68k to ~22k) or a MV so Im trawling for info on these ideas.

Anyway Im glad to say all's finally achieved- here she is with my diy case:
http://i102.photobucket.com/albums/m106/TheCaptain_02/Picture284.jpg

http://i102.photobucket.com/albums/m106/TheCaptain_02/Picture282.jpg

Captain.