-JJ BIAS RESISTOR MOD-

[sg guy]

-anyone done this yet? I use a variac at 90-ish volts, not sure of the value of the stock bias resistor in the JJ,.. if anyone has done this mod what value resistor did you use,.. also considering replacing the trim pot for more sweep-

 

[GregM]

...and on the subject of the bias trim pot, if anybody can post or PM a pic of the JJ trim pot I'd appreciate it.

 

[Fox77]

What does this mod achieve? I have a JJ and am curious

 

[Chester Nimitz]

What does this mod achieve? I have a JJ and am curious

?

 

[Fox77]

What does this mod achieve? I have a JJ and am curious

?

Just wanted to know what a bias resistor mod does to the amp. I'm not very technical...

Thanks!

 

[sg guy]

-in my case, using a variac at 90v's,... i cant get the bias in range,.... so i need to change the bias resistor to do so,... some other's may want to try different tubes-(6L6's/KT88's etc.)-

 

[Fox77]

Got it. Thanks

 

[RACKSYSTEMS]

There is a 47k resistor in series with the bias pot. You could parallel say a 100k over it. Should be good then.

 

[sg guy]

-thanx dave-