Univox u1011 & u1226 schematics - thoughts about the differences ?

[tubemonster]

I was checking out all the schematics in this pdf that has a bunch of Univox schematics in it and I noticed that the U1226 and U1011 are essentially the same short of one having two 6L6's and the other having 4 6L6's.

But, there are a couple differences that have me wondering if they are schematic typo's or if that's the way the actual amps are built.

Just wondering what others may think are typo's or not for either schematic, what they might change or not, etc.

I have a u1011 and mine is wired up like the one in U1011 schematic, except for the slope resistor is 270K like in the U1226 schematic and the cap in the tremolo circuit is a .47 tantalum cap (not .5uf or 5uf).

I'm just curious more than anything I guess.

Here some attached schematics.
The u1226 and u1011 have the differences that I'm talking about highlighted on them.
The other pdf is the collection of Univox schematics.

Univox_U-1226_LEAD_AMP_new.pdf

Univox_U-1011_LEAD_AMP_new.pdf

UniVox Amp Schematics.pdf

[tubemonster]

P.S. On my amp, the .005uf cap on channel one shown in between the .02uf and 500pf caps on the schematic, is mounted on the bass potentiometer.

[loudthud]

Most older schematics you find floating around the internet are not the Official Factory Schematics, they are something that somebody scanned and posted somewhere. When things are scanned, some of the hand written characters become unreadable unless you want a file that is four or more times the size it needs to be. Many times someone goes in and touches up the unreadable characters and mistakes occur. Often times decimal points disappear.

290K is not a standard value, and I doubt Univox had custom resistors made. 0.47uF is just a production change because 0.5uF could not be obtained at the time.

These schematics are not going to exactly match your amp. Get over it.

[gui_tarzan]

My 1946 Harmony has some odd values, so does the Teisco Checkmate Stereo Pre-Amp I've been working on lately. The schematic for the latter doesn't exist so I made one using the values that are in a similar Teisco and what came in the amp. It is what it is, sometimes you have to compare other similar schematics and use the math to get the right values.

[Enzo]

Long ago they used what we now call non-standard values, like 250k resistors and 5uf caps. But then they came up with the standard value sequence and we all switched to that. SO instead of 2uf we get 2.2uf. Instead of 5uf we get 4.7uf. and so on. And really, 5uf and 4.7uf are the same part.

[tubemonster]

Not concerned about it matching or not matching the amp I have really, the differences just kind of peaked my curiosity is all.
First time owning one of these bigger Univox amps and enjoying the univox ride for a while.

The things that stuck out to me were the cathode bypass cap values for channel one and two.
The schematics have the .68uf and 100uf doing the vice-versa thing, but both schematics have the .005uF and 500pf and reverb connection, etc the same.
Also, .5 and 5uF are fairly different values on the tremolo circuit.

Anyways, just a curious conversation thing.

Who knows, maybe someone with a U1226 might weigh in one day and do the whole - mine are like the u1226 schematic

P.S. I get the whole .5/.47, etc, value/standard thing, although I do appreciate the heads up info for sure, if I don't state something how would you know if I know, know what I mean.
My bad, I guess I should have stated something more along the lines of my amp has the .5/.47 type thing.
Anyways, it's all good in amp'land - lol...

[teemuk]

Schematic is just representative of specific era. Manufacturers often change the design even when the amplifier is under production. The longer it is the more likely the design has alternative revisions. Sometimes design changes slightly, sometimes a lot. Look at Roland JC-120 from 1978 versus 1985 for example, they are totally different amps! One component change somewhere is peanuts. Also, a model name is just model name. Peavey has made probably a dozen of different kinds of "Bandit" amps.

[Enzo]

Agree^^^

Peavey "Bandit" is like a Chevrolet "Impala".

[tubemonster]

Agree^^^

Peavey "Bandit" is like a Chevrolet "Impala".

I know a guy that was using the Peavey bandits to gig out in blues and jazz bands - loved them - had like three of them.

I'm a fan of the peavey bandits myself, but of course I'm a fan of a bunch of peavey usa stuff - lol.

[tubemonster]

I'm going to have to keep my eye's open for a Univox 1226, I want to open it up and compare it to my 1011.
Like I said, just curious