Peavey Ultra Plus - dead...

[Twangmaster]

Hi Enzo and Amp Cat !

No, there is no problem. Pin 1 on a 6L6 is not used, so the cicuit board designer can feel free to put anything he wants on pin 1. All pin 1 is anymore is a spot on the road from one pace to another.

The heaters run on about 6VAC. That means there is about 6 volts AC from pin 2 to pin 7 on a 6L6. But you are measuring from chassis, and that 6v AC power transformer winding has a grounded center, one way or another. So you get 3volts on one side and 3 volts on the other. But that adds up to 6 volts across. If the tubes light up inside, then the heater volts are OK.

Thanks a lot for the help - the amp is running and sounds great, however the new TAD 6L6's are running extremely hot, so I am really considaring to install adjustable bias for each tube - and since I'm not that knowledable about tubes, I would like to hear if any of you could give me exact advice on how and where to install the adjustable bias?

Thanks again for you great help!

Gowe

BTW one of the preamp tubes were bad, and after renewing it, the heater came on all the preamamp tubes.

[Enzo]

Verify the voltages at ALL power tubes. It is rare for a stock PV amp to get its power tubes hot. The amps generally run them quite cool. Thus I would be concerned there was a problem instead of a need for ajustment. Of course I could be wrong.

[Twangmaster]

Verify the voltages at ALL power tubes. It is rare for a stock PV amp to get its power tubes hot. The amps generally run them quite cool. Thus I would be concerned there was a problem instead of a need for ajustment. Of course I could be wrong.

Hi again,

I measured 495 v at all output tubes - I haven't measured bias though.
Could you tell me where in the circuit I can insert pots to make the bias adjustable?

Thanks,
Gowe

[Enzo]

But bias is the most important reading. We already know the B+ is there or it wouldn't amplify. I want to know if EVERY power tube has about -50v on the grid. If any are much lower, then there is the problem.

Get the schematic from PV parts if you don't have it. Then we can talk about R123 and C456 or whatever.

[Twangmaster]

But bias is the most important reading. We already know the B+ is there or it wouldn't amplify. I want to know if EVERY power tube has about -50v on the grid. If any are much lower, then there is the problem.

Get the schematic from PV parts if you don't have it. Then we can talk about R123 and C456 or whatever.

Hi Enzo,

They are all around -48v - but the power tubes are glowing purple, and hiss for about 30 seconds after I switch the standby on - that doesn't seem right.

I get the scematic - but just now I'm off to Alsace for holidays - hope you'll be there when I'm bach in about 2 weeks.

Thanks a lot.
Gowe

[Nathuse]

Hi,

I'm french and that's the first I post into this forum.
I'm sorry for my langage...
I've got the ultra plus guitar head but it breaks few days ago.
on part of the electronics composants has burn, so I'm searching after the electronic schema in order to repare my head.
Is there somebody who can help me to find the electronic schema of the ultra plus guitar head (peavey)?
thank you

Nath

[Enzo]

Hi Nath, welcome to the forum.

Two things.

First, send an email to Peavey and request the schematics. Parts@peavey.com or repair@peavey.com They will email them to you.

Second, I suggest you start a new thread here for your amplifier. This thread is a year old and not active any longer. You will get better response that way.

[Nathuse]

thanks and sorry