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previous: Peter S Anyone have any opinions on changin... -- 9/13/2000 8:55 PM

Re: Output tube Grid Resistors

9/13/2000 10:49 PM
Richie{~}==:::	Re: Output tube Grid Resistors Peter: Seems like they use different values for the type tube that is used. In the JCM 800..use the 150k for the 6550..and 220k for EL34.. And i see in fenders they use different values.. If you look at the schematics.. you'll see that usually the plate resistor on the PI/driver will be say 82k and 100k when useing the 220k bias resistors.. if the plate resistors are different..like in some of the Fenders CBS amps they use 47k and 82k in marshalls or 100k..then the bias resistors are different.. Now.. all this jibberish.. My opinion is i like the 220k and the 82k 100k plate resistors..Because this is tested, tried, used, and works in marshalls and bassmans,etc.. It must be the voltage of the plate resistors to the gain of the PI/driver of the tube used, that makes this setting. I'm sure someone has the answer..but it must be to balance the voltage gain according to bias resistors used..to match what power tubes and how much gain is feed into them..And the other thing is the type PI tube used...if it is 12AX7 or 12At7 etc.. Richie{~}==:::

9/13/2000 10:49 PM

Richie{~}==:::

Re: Output tube Grid Resistors

Peter: Seems like they use different values for the type tube that is used. In the JCM 800..use the 150k for the 6550..and 220k for EL34.. And i see in fenders they use different values.. If you look at the schematics.. you'll see that usually the plate resistor on the PI/driver will be say 82k and 100k when useing the 220k bias resistors.. if the plate resistors are different..like in some of the Fenders CBS amps they use 47k and 82k in marshalls or 100k..then the bias resistors are different.. Now.. all this jibberish.. My opinion is i like the 220k and the 82k 100k plate resistors..Because this is tested, tried, used, and works in marshalls and bassmans,etc..
It must be the voltage of the plate resistors to the gain of the PI/driver of the tube used, that makes this setting.
I'm sure someone has the answer..but it must be to balance the voltage gain according to bias resistors used..to match what power tubes and how much gain is feed into them..And the other thing is the type PI tube used...if it is 12AX7 or 12At7 etc..
Richie{~}==:::

Replies:

nuke The ouput tube grid-to-ground (or b... -- 9/13/2000 11:37 PM
Dave H. Grid leak resistors of 100k or less... -- 9/14/2000 1:19 PM