CA y 'est!! je sais ou se trouve les resistances pour le Bias.
elle se trouve entre les 2 condensateur de 220Uf sous la COLLE.
Merci à Douglas MCCALLUM qui avait posté sur le site de firebottle, merci damienb.
voici une photo :
J'aurai du men douter, le seule endroit ou ya de la colle c'est ICI sur les resistances de BIAS, AH lalala les petits cachotiers!
Bon apres avoir enlevé la colle , on apercoi bien les 2 resistances , une de 47K et une de 470 ohm.
Voila le message de douglas donnant plus d'explications: :
There is no adjustment for bias in the Peavey Ultra. It is designed for you to plug the new tubes into the sockets and play - no adjustment needed. I recommend you try that first - just plug in the new tubes and play the amp.
It is possible to modify the amp for adjustable bias, but you would need to change two resistors, not just one. R98 is only 470 ohms. This would be increased to about 3000 to 5000 ohms. Then R99 which is presently 47k ohms would be replaced by a variable resistor of similar value.
For safety, I prefer not to use a simple variable resistor because it could be turned to zero, and that would result in a lack of bias. I instead use for example a 22k resistor and a 25k potentiometer in series for the function. That way if I turn the 25k pot to zero I still have the 22k as a limit. Or perhaps a 10k pot with a 33k or 39k resistor.
To identify those resistors on the board, straight behind the ULTRA POST and BOTTOM controls you will see two capacitors 200uf 75v next to each other. The two resistors are hidden between them.
