Peavey Renown 212 Transformer Wiring

[GiovannyS10]

Hey guys,
I got a Peavey Renown for fix here, but it has a kind of output transformer. It was not working and was shocking everyone who tried to use it. Hahah - i could fix it (was my first time with a amplifier like this) after it i thought that was time for replace the audio jacks from the back panel, and guess? I just don't know how to wire it correctly again and i was sure that i took a pic of this area but not  I really don't know how those transformers works and my research was not too productive. If someone can help me - i thank.
I have 4 wires in the transformer.
Yellow = is connected directly from the SPK +
Black = ?
Red = ?
Blue = ?
I have a #5 wire blue too from the SPK -, i guess that it is connected to the blue one on transformer, but i wired this way and not worked. I am not sure about if i wired the preamp station right too.











Thank you guys for helping! 

[thermionix]

Though I'm not familiar with the Renown, or really the use of OTs in solid state amps, there seems to be an unofficial standard when it comes to wire colors in American-made amps.  Yellow and black would likely be the secondary (+ and - of the speaker) and blue and red would be the primary, with red going to the voltage supply and blue to the output of the power transistor(s).  This may help, I don't know, but best bet is to track down a schematic.  If you can't find one, the folks at Peavey are usually willing to help.  Send them an email.  Might be good to tell them the serial number of the amp you have, as there may be different versions.

[thermionix]

I should add, use a meter to verify continuity between wires.  If you get continuity between yellow and black, and then between red and blue, that would probably indicate secondary and primary.

On a tube OT, usually the secondary reads less than 2 ohms resistance.  The primary would be more like 30 to 100 ohms.  Not sure what to look for in a solid state OT, but I would guess the primary would have a higher DC resistance still.

[GiovannyS10]

Hey guy thank you for all. The Yellow is part of primary. I used a meter and i really guess the primary is blue + yellow. But why it not worked when i connected the speaker - (from the board) to the blue and wired the speakers to black and red? I don't know. So i continue thinking it is wrong. I writed to Peavey they said can't help me until has a Renown there for take a pic for me, but they sent me the schematic which helped me a lot to fix another things, anyway is not cleared to me how to wire this one. The transformer colors in schematic is different than mine, anyway i just ignored it and tried to follow it, and guess? Not worked '-' Maybe i am just wiring wrong - i am really lost. Haha - before this i only fixes active speakers and general use amplifiers - not a huge transistor guitar amp like this but i already did a lot. Fixed the biasing voltages, replaced the mains transistors, replaced ALL electrolytic and put it to work and it screams so high!!!!! Roar! But i had the idea of change that jacks and see? Crap all my work 

I attached the schematic that Peavey sent me below, maybe it will help us to have a better idea about this:

[GiovannyS10]

Here is my measurement results:
Yellow + Blue = 0,9Ω
Red + Black = 1,5 Ω
Blue + Red = 1,3Ω
Blue + Black = 1,6Ω
Yellow + Red = 1,3Ω
Yellow + Black = 1,3Ω

I think it's all the possible combinations hahah But anyway i am sure that yellow is primary because it is wired directly to board speaker + out (without soldering - an intact wire). So I think the measurement not helps so much

Remember this transformer come from the speaker out board and end to the speaker. Maybe it is wired inverse no? Yellow/Black Primary and Blue/Red Secondary?

[thermionix]

Okay, looking at the schematic, that's not an output transformer in the traditional sense, with a primary and secondary.  I guess it's just a way to match up the speaker impedances with the power amp, but I'm not familiar with that method.  I can't tell what's what from your DC resistance readings.

[Phoenix]

That's not a traditional output isolation transformer, it's an autotransformer that allows you to get maximum power from the solid state power amp regardless of speaker impedance (normally as you increase speaker impedance you'd loose power).
Now, if your resistance measurements are accurate (difficult with most multimeters with such low resistances - do you have an ESR meter, 4 wire bench meter or other instrument designed for low resistance ranges?), and assuming that black is common (default standard and a safe bet), then it would appear that yellow is 4 ohm, red is 8 ohm, and blue is 16 ohm.
You can confirm this by injecting a signal into the amp with a signal generator, and measuring the voltage at each of the taps - whichever tap outputs the lowest voltage is the 4 ohm, highest is 16 ohm. Rewire as necessary.
You mentioned that the amp was shocking people, and that you've replaced some transistors and caps, but you didn't say that you've identified what was causing people to be shocked, have you found that yet?

Good luck, hope this helps.

[PRR]

> what was causing people to be shocked

Yes, yes, yes! Fix the shock FIRST!!

This is a transitional product. It shows a proper 3-pin plug, but it also has a Ground Switch. In 1981, in many houses, you'd cut off the ground pin and flip the ground switch for least buzz (may not be least shock). But it is 2017 already! Don't play dives that do not have (working!) 3-pin outlets! (Don't come to my new house.) Then put a proper 3-pin plug on, green to chassis, and cut all the wires off the Ground Switch. (Leave the do-nothing switch for "authenticity".)

Ah, the 230V version is different. Still be SURE the wall-ground goes to chassis no-fail.

> ......and blue is 16 ohm...

No reason to assume standard values. Re-draw the mess.


Clearly the 2 and 4 jack leads are as marked, and the amp output seems to go to an in-between tap. And some guesswork says the amp needs around 3 Ohms to make the claimed 160 Watts. Which is indeed in-between 2 and 4.

I suspect they had a 2-pair 110W 4 Ohm amp, wanted to market a 160W amp with 2 and 4 Ohm speaker cabinets. A 3-pair hack makes the power but in ~~3 Ohms. The autotransformer matches 2 or 4 to 3.

Note the speaker jacks do NOT go to chassis as usual. This is a small point related to current-sensing NFB.

[GiovannyS10]

Hey guys, thank you all for replying.
So i have not a too accurate tool for measuring it. I have two multimeters: 1 of bad quality and another a quite better.
I already fixed the shocks, the problem was in the grounding method. Another guy before me tried to fix it, he replaced ALL of the transistors from another 4 different references. The transistors was not working fine. So i replaced it for new 6 MJ15003 original made in Mexico. This amp was originally made for used in 110V but here its 220V, the guy re-did the main transformer for it works well at 220 but forgot to change the the power circuit for 220, so the GND switch continued in the circuit, but not working well. I redid the power circuit following the schematic and removed the GND switch from it. Grounded the chassis as is correct and it worked so fine and no shocks until now. Uh, o forget to say i replaced the huge filter capacitors, and enjoyed the time for replace all the eletrolytics too, this amp is too old. Sure some eletrolytics was not so good than it must be.
After it the amplifier worked okay, but the sound was distorting (like an overdrive) in the clean channel in high volume. I was trying to fix it when decided to replace the back jacks and forgot how to wire this transformer.
Got it?

This is a transitional product. It shows a proper 3-pin plug, but it also has a Ground Switch. In 1981, in many houses, you'd cut off the ground pin and flip the ground switch for least buzz (may not be least shock). But it is 2017 already! Don't play dives that do not have (working!) 3-pin outlets! (Don't come to my new house.) Then put a proper 3-pin plug on, green to chassis, and cut all the wires off the Ground Switch. (Leave the do-nothing switch for "authenticity".)

I already cared about this. I added the 3 Pin outlet connector.

Ah, the 230V version is different. Still be SURE the wall-ground goes to chassis no-fail.

I did it, sure! Working, no fail!

But about the transformer i assumed that black is GND. In drawing we can see that the Green is the minor resistance with black; Blue is the #2 one; and White is the bigger resistance. So i guess that:
Black = Black
Green = Blue
Blue = Yellow
White = Red
(left schematic colors; right my transformer colors)
I re did the measurement using the better multimeter for a better accurate measurement and i got it (values in ohms):
Black + Yellow = 1,8
Black + Red = 2,0
Black + Blue = 1,6
So i suppose it is correct and the logic is valid. What you think? Anyway is not cleared to me how to wire the Green (Blue) is it to GND?

Note the speaker jacks do NOT go to chassis as usual. This is a small point related to current-sensing NFB.

I am confused with it too. So must i DO NOT ground the jack sleeve, right? Only wire it to transformer Black + Board Speaker - together?

[teemuk]

I am confused with it too. So must i DO NOT ground the jack sleeve, right? Only wire it to transformer Black + Board Speaker - together?

Yes. Make sure jack sleeve is isolated from ground/common. (Load) current flow has to be generated through those low-resistance (parallel) "current sampling" resistors in order to make feedback work as designed. The resistors are in series with the load, but if you ground the speaker terminal you bypass them and prevent current flow.

[GiovannyS10]

I am confused with it too. So must i DO NOT ground the jack sleeve, right? Only wire it to transformer Black + Board Speaker - together?

Yes. Make sure jack sleeve is isolated from ground/common. (Load) current flow has to be generated through those low-resistance (parallel) "current sampling" resistors in order to make feedback work as designed. The resistors are in series with the load, but if you ground the speaker terminal you bypass them and prevent current flow.

So i guess that the same idea is applied to the guitar input, right? Because so far seems it is shorted in the schematic.

[Phoenix]

So i guess that the same idea is applied to the guitar input, right? Because so far seems it is shorted in the schematic.

No, the input goes directly to ground - it does not need an insulated jack. It's just the speaker output jacks that need to be insulated, they were fitted with shoulder washers originally.

[GiovannyS10]

Okay Phoenix,
I just checked now and i have ground in input but not in speakers output jacks, as was expected! Perfect!

And i think a got a bad interpretation of this part. I thought that i need to ground the input lug, but it was not making sense in my head, now i see, i shall ground it when disconnected... Now it makes sense. Haha I am rewiring the transformer now, i will say if it will work okay.

[GiovannyS10]

Hey guys, i could see the original wires color very close to the transformer, so now i am sure about the relation:
White = Blue
Green = Red
Blue = Yellow
Black = Black
I wired it okay now and it back to work. And i saw that the output jacks was wired to ground, i fixed it and now it is surely isolated from GND

But i have some things to fix now:
1. I got an "overdrive" sound in the clean channel;
2. The 'high gain' input isn't work - only mute sound;
3. Got a buzz while playing (like bad ground), but i am sure all is grounded correctly, i just isolated the output jacks.

Thank you for all you guys who is engaged in help

[thermionix]

2. The 'high gain' input isn't work - only mute sound;

It's a switched jack, sounds like the contact isn't breaking when you insert the plug.  If it's an open jack, should be easy to spot visually.  If it's enclosed, you'll have to use an ohmmeter or continuity tester*.  That's about the only reason I can see why you get no sound from just the high gain input.  Unless someone has rewired it, then who knows.

*With just a cable plugged into the high gain jack, no guitar or pedal on the other end, see if you get zero or very low ohms from tip to sleeve (ground).

1. I got an "overdrive" sound in the clean channel;

When the power transistors were replaced, was a matched set used?  I'm not really sure if that's necessary, but I think so.  Could be a reason you can't get a clean sound.

[GiovannyS10]

Hey thermionix,
The jack is okay, i already checked the contact and it's okay; No contact to ground when plug the cable... 

I do not think the problem is matching, but anyway i tried to get it with resistances more close that i could source. But not really matched. Maybe the problem is only select the correct channel hahahaha. I don't know yet.