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.