Champ 2w OT (I think).. Q's

[Sea Chief]

Hi chaps-

got myself a self-built p-to-p 5F1 amp from someone I know: it has an odd xfmr assortment, but works (& sounds pretty good). The circuit/ board I checked over and as per a std tweed 5F1. 5y3/ 6v6gt/ 12ax7.

Few Q's I need help on tho. First are the xfmrs. It has a Vyse OT: very small and afaict only 2w (told it was from a Vyse Champ but its size and relatively low volume does suggest it is a 2w, not a larger sized 5w I was expecting, of whatever quality it may have been). The PT is from the seller's amp tech, who rewound a fender PT from 70's from 110v to 230v, for use in a Champ- presumably to Champ specs: its 325v-0-325v with the usual 5v and 6.3v secondaries. The Q is whether the PT (quite a lump/ ~same size as a tweed deluxe PT) and the small 2w OT are ok together (and whether it can be called a Champ if 2w?). This tiddler OT is actually quality uk-made as Vyse's xfmrs are which is good to know, not some chinese junk.

2nd Q is the OT output: its wired from the 4 ohm tap (I think this is std Champ) and Im testing via a 5w 4 ohm radio spkr. As its got 4/8/16ohm secondaries it would save me buying a 4ohm speaker (another spend I could do without at the mo) if I could use it into my 8 Ohm 1x12" speaker cabinet (~50w/ its a bog std eminence type, peavey labelled). Is this an ok idea? or will the essence of the Champ be lost/ is one of the main ingredients for that tone dialed-up tone inherrant to its 4 ohm 8" speaker.. and if ok, will the 12" higher w rating of 50w mean it stays clean dialed up- or it ain't neccessarily so?

Thank, Sea Chief.

[Leo_Gnardo]

1: if the PT and OT have been working together well so far, should continue, why not. I'd like to see a 5W OT less likely to fail when driven hard but so far so good.

2: You can run an 8 ohm speaker from your 4 ohm OT secondary. The price is a small loss of power but shouldnt' be a major problem. Go ahead try your 50W twelve, you're not going to blow it up or anything. If it sounds good, that's what counts. If you like the combination, sometime when you have the dosh buy a 5W OT that has 8 ohm secondary and maybe others like 4 and 16. I can't say I've heard of Vyse but if you're satisfied must be OK.

Also one of the failure modes of the Champ, as well as many other amps, you jam away at volume 10, can get an arc going between the plate pin 3 and filament pin 2. Just had one in like this. The output tube was wrecked, but I was able to use a Dremel mini grinder to remove the carbonised part of the socket. For this one, all the rest needed was a new fuse and 6V6. But it COULD have wrecked the OT. One cheap preventive move too - 3 series wired 1N4007 rectifiers (1 amp, 1000V rated) wired from plate to ground, the cathode (stripe) side of the rectifiers at the plate. Put 'em in back'ards and you'll be drawing full current thru the OT maybe wreck it fast so no misteaks please.

How's your 400 yard neighbor, the git with the extra sensitive hearing? I always worry that he'll be back to hassle you.

[g1]

2: You can run an 8 ohm speaker from your 4 ohm OT secondary. The price is a small loss of power but shouldnt' be a major problem.

Leo, he did mention it also has 8 and 16 ohm taps.
But perhaps you mean he can test it without rewiring, which I would agree should be fine.

[mcgruff]

2nd Q is the OT output: its wired from the 4 ohm tap (I think this is std Champ) and Im testing via a 5w 4 ohm radio spkr. As its got 4/8/16ohm secondaries it would save me buying a 4ohm speaker (another spend I could do without at the mo) if I could use it into my 8 Ohm 1x12" speaker cabinet (~50w/ its a bog std eminence type, peavey labelled). Is this an ok idea? or will the essence of the Champ be lost/ is one of the main ingredients for that tone dialed-up tone inherrant to its 4 ohm 8" speaker.. and if ok, will the 12" higher w rating of 50w mean it stays clean dialed up- or it ain't neccessarily so?

The original Champ speaker/cab is definitely part of the original mojo however that doesn't mean it won't sound good with alternatives - just different. A speaker with a much higher wattage rating won't have much cone breakup but the amp will start clipping at exactly the same point as before. I play my own champ through a 1x12 loaded with a V30 and it still gets pretty dirty.

[Leo_Gnardo]

The original Champ speaker/cab is definitely part of the original mojo however that doesn't mean it won't sound good with alternatives - just different. A speaker with a much higher wattage rating won't have much cone breakup but the amp will start clipping at exactly the same point as before. I play my own champ through a 1x12 loaded with a V30 and it still gets pretty dirty.

+1 Champs and similar small amps sound wonderful thru big speakers. Customers can't believe how amazing their little gems sound when I plug 'em into my 4x12 with Altecs. "You can DO that?" The amp doesn't care how big the speaker is, just would like an impedance match. You can whup that amp up to 13 and talk over the guitar racket which never exceeds a polite volume.

g-one, WOOPS you're 100% correct, it's right there in black and . . . grey my bg color. Of course attach the 8 ohm speaker to the appropriate tap. Geez I used to get good marks in reading comprehension. So much for that. My mind is a terrible thing. Used to work so well. 50 years ago.

[Sea Chief]

Hi Chaps-

grateful for the info here. (Yes OT does have the 8 Ohm tap) Ok good so I'll try into the 50w spkr 8Ohm and see how it sounds: but any more loss of volume than it has already at its diminutive 2w and I'm struggling a bit (tho git n'bor won't be stomping over! I thought he was perfectly reasonable to do so actually- that 5E3 was a ferocious vol, tho his comment on my gtr playing "that's rubbish as well" were poor. My gtr playing is f**king great). But if it sounds good via the 8Ohm 12" (surely better than a test 5w hifi spkr!) should I make a bline to rewire from the 8Ohm tap, or not bother/ no mismatch load issues at all to worry about (albeit the 'safer' way round)?

Anyone hearing of an amp tech rewinding PT's? apparantly he's been 1st port of call for some serious musos' amps (ChuckBerry) whilst on tour in Europe, so his credentials stack up/ cant get much more of a tricky customer than ChuckB!

Well then.. will I actually find some OD at last?!? a holy grail for me after so many years/ so many amps, thats why I bought the small Champ as a test really/ Im jacking it all in if I dont get any break up with this damn amp. My bet is I don't get any/ or the bare minimum. All going in the river if so/ last gasp for me.

Thanks Sea Chief.

[eschertron]

A couple things I did to my Champion 600 included a tone stack lift (to make it more like the 5F1), and some resized caps to reduce the 'fartiness' at high volume. With that, plugged into a 2X12 open-back cab, I was in single-ended growl heaven I think you'll be pleased with your new amp.

[Jazz P Bass]

[QUOTE=Sea Chief;360918](Yes OT does have the 8 Ohm tap) Ok good so I'll try into the 50w spkr 8Ohm and see how it sounds: but any more loss of volume than it has already at its diminutive 2w and I'm struggling a bitQUOTE]

As an aside, the 2 watt OT rating is the amount of current that the transformer can handle.
The output tube is what supplies the power.

So hit a 2 watt OT with 5 watts & it will get hot.
It has nothing to do with volume.

[Leo_Gnardo]

1: If you have the option, and you do, then wire your 8 ohm speaker to the 8 ohm tap. Most often the best thing to do. For a quick check, you'll get away with the mismatch as long as you're not blasting away at full rip. Why not put in output jacks to access each tap? Cheaper than a switch. Mesa Boogie do that, like their amps or not. Very convenient.

2: Rewinder tech, wow that's a lot of work. While in the UK it's easy enough to find autoformers to step 240V down to 120V and not all that expensive. Plenty of hire amps built in 120V countries, have the autoformer bolted to the floor of the combo and a UK plug hanging out the back. On tour? The PA company will supply a nice piglet for your stage, stepdown auto or transformer sometimes with a voltage adjustment switch. Well the good PA outfits anyway, I've been lucky to have Cane Green or similar outfits do PA for the tours I've worked in Old Blighty.

3: Chuck Berry a tricky customer? Well I expect he just wants his amps to sound right, gotta expect that. If he pays the bill, all is good. Some of my muso friends have played in the "local muso" bands he hires for appearances. Smart businessman to not hire a permanent band. Spread the wealth a little, and give the locals something to talk about. My friends told me, he's a joy to work with as long as you don't overplay. Good advice. Support the music. Don't solo constantly.

4: We all hope your Champ project comes out satisfactory for you. Don't give up if not. With the 5E3 still at hand - it IS still there I hope - you can try an old rocker trick, use the small amp as a preamp substituting a resistor for the speaker, and send the speaker signal via volume pot off to the input of your larger amp. Seen it done, and you may have heard it on recordings. I was always a fan of Robin Trower's early playing with Procol Harum 1967-71. Some scary awesome tones. (Check "Repent Walpurgis" and the scale runup and solo on "Whaling Stories" for examples.) One day I ran across him at Bearsville Studio (he was producing another muso's album) and he was kind enough to try and answer my question about how he got some of those tones. "Gibson guitar and some old Fender amp." Lucky for us Chris Michie who worked as a recording assistant remembered more, and left his memories on the PH fan website "Beyond The Pale." Chris remembers Robin using a Selmer student amp - a simple one similar to a Champ, perhaps a Little Giant - as a preamp. Oh, yesssss, now that's a good answer. Worth a try. Hope it doesn't summon Mr. Grinch at 400 yd distance, heh heh heh.... Maybe he likes quiet jazz guitar, Wes Montgomery, Joe Pass, like that. There's something for everybody.

[Sea Chief]

Hi chaps-

Intersting that JazzP.. I noticed the amp getting pretty hot, the PT quite toasty in particular. I hope that's nothing to worry about. It'll keep me warm in t'winter anyroad.

Ok good plan- two sockets 4ohm/ 8ohm it is. Im building a cab for it anyway (a bitch as its in a Champion chassis- a silly little thing- but gonna switch it round to front and have a lil' blackfacetweedtiddler. I might TM that) so will add a socket on the panel. It'll have a blank for an 8" spkr until I can find a 4 ohm w'out spending another £40+.. or will there be any difference with an 8" 8ohm? these I can find a cheapy for £10 from say an old 'frontman15' cab for eg on ebay/ do the job for me as Im skint as usual!

5E3 went in the river. Prolly got fishies in it innit.

Thanks Sea Chief.

[Leo_Gnardo]

5E3 went in the river. Prolly got fishies in it innit.

Ohhh noooo...... I hope not really. Mr Sensitive Hearing should be the one swimming with the herrings.

If you can fish it out, one of my customers, a Grammy-winning record producer who has his ears "on", claimed his mid 50's tweed Deluxe sounded BETTER dried out after it had been floating in 4-foot deep water in his livingroom during a flood.

[Sea Chief]

Well I never. Are you sure he had his ears "on", they might have some oily flood wax in 'em.

So what would be the difference be.. between the OT's 4ohm tap into a 4 ohm 8" spkr, and OT's 8ohm tap > 8ohm 8" spkr? volume, nothing at all, cone break-up thingywhatnot shenanigans?

[Jazz P Bass]

So what would be the difference be.. between the OT's 4ohm tap into a 4 ohm 8" spkr, and OT's 8ohm tap > 8ohm 8" spkr? volume, nothing at all, cone break-up thingywhatnot shenanigans?

A mismatch between the expected speaker load & the OT winding will result in less power being transfered to the speaker.
(and possible damage to the OT)

[Leo_Gnardo]

Well I never. Are you sure he had his ears "on", they might have some oily flood wax in 'em.

Good enough to produce BB King and Natalie Merchant. I'd give him credit for having his ears on. Oh and he's English too, so enjoys a good wind up like you're trying to deliver. But I'd still not recommend anyone soak their prize amp to find this "improvement." (A couple years later it didn't work for Bruce Springsteen but that's another story.) I'd count him as lucky. Besides talented. Good chap all around.

So what would be the difference be.. between the OT's 4ohm tap into a 4 ohm 8" spkr, and OT's 8ohm tap > 8ohm 8" spkr? volume, nothing at all, cone break-up thingywhatnot shenanigans?

IF you had speakers 4 and 8 ohm otherwise identical, you'd be hard put to tell the diff. The amp doesn't care what's the diameter or quantity of speakers, just looking for a friendly ohms match.

There is a bit of discussion about tone differences between cabinet wirings & OT tap choices but I think those guys are arguing over the last apple in the barrel, if you catch my drift. With a small speaker, 8 inches, go back to the top of previous paragraph.

Enough theorizing, hook up the speaker and have a listen, you'll probably like what you hear. I get knocked for being an "empiricist" wow big word but that's what's in this paragraph. What matters is, does it sound good? To you? Only one way to find out. Calculaton and conjecture won't tell you. Amp meet speaker, speaker meet amp, let's rock already. Before we get too old. put white haired geezer OAP smiley thing here.

[Sea Chief]

Ok he had his ears on then. Natalie Merchant- lovely voice but if only that 10,000 maniacs album wasn't such simpleton's 123 songwriting! fine vox but In My Tribe makes my teeth gnash). Anyway where was I- oh yes right an 8Ohm spkr it shall be then- seem way more plentiful and cheaper as a consequence I guess.

Off to build the blackfacetweedtiddler then! watch this space- pics soon.

Thanks all- Chief.