Peavey Windsor Studio The output tube el 34 bournd out

[debuc1234]

Peavey Windsor Studio The output tube el 34 bournd out

I tjeck the plate voltage et is 470V thes is too heigh for a class a se amp.
Problem Peavy winsor studio EL 34 bound out Help

I thing i shut be around 270V.
I think Peavy has installd the rong transformer HT

http://dl.dropbox.com/u/19526767/Pea...tudio/scan.pdf

Is ther enybobby who has tjekt the plate voltage. is et around 270V ????

Br

Thomas from Denmark

[MWJB]

470vdc sounds about right. You could install a larger cathode resistor on the EL34 but voltage will rise again. The cathode voltage is subtracted from the plate voltage so that 470 is really more like 430-435v.

Nobody makes, or has ever commercially made an EL34 guitar amp with 270v on the plate. Output would be very low indeed.

[debuc1234]

But the amp is a class A SE, only 1 output tube
Spec :
TDSL Tube data [EL34]

[MWJB]

Yes, I understand. Nevertheless 470vdc sounds more realistic than 270vdc. I run a JJ6V6 at 470vdc in my SE amp. The guys who write the data sheets don't build the guitar amps that the tubes ultimately end up in. All popular guitar amps run the tubes at higher voltages than the data sheets suggest.

[Jazz P Bass]

The scan is not very crisp, I cannot make out the voltage rating of C10, C42 & C47.
It "looks" like 500V.
If that is the case, 475 Vdc on the plates sounds about right.
Peavey certainly would have used a lower voltage rating if the plates where a lot lower.

[debuc1234]

To MWJB ok i take youre word for et, so the cure es a larger cathode resistor 1K- 2K ? and et will run in Class A ?

To Jazz P bass yes et es 500V

Br
Thomas

[MWJB]

It can't run AB as there is only one power tube, it will run SE closer to cut-off rather than symmetrically biased....as nearly all SE guitar amps do.

[debuc1234]

Ok so the reason the EL34 bournd, was thad the amp wore biased wrongly.
power anode (Wa) Ua 465- Uc 28 * Ia 72mA= 31W and max is 25W
i will giv et a go rebaising it. or do you have odder triks op youes sleve..

And thanks MWJB

Br

Thomas

[Enzo]

Do not assume the tube failed because some voltage was wrong. Tubes also fail on their own from things like vibration.

Here is a crisp pdf copy

[debuc1234]

Hi enzo thanks
I traid lovering plate voltage to 250V and Rk= 100Ohm , amp sounds nice, i clean. Have to fix drive i dosent sound good.

br

Thomas

[Enzo]

I just looked in my RCA tube book to verify, the EL34 is rated to 800 volts on the plate with 425 on the screen on Class A circuits.

Peavey did not make any mistakes.

[debuc1234]

Hi Enzo
oki for a SE Class A Pentode singel tube. Hmm
Ok so the reason the EL34 bournd, was wrongly biased .
power anode (Wa) Ua 465- Uc 28 * Ia 72mA= 31W and max is 25W
i rebaising it. Rk (1k - 2K) or do you have odder triks op youes sleve..
Br
Thomas

[debuc1234]

NB excuse my spelling is not used to writing in English