independant adjustable bias 4 peavey bravo..please help

[ampstepper]

hi can anyone sus out independant adjustable bias 4 peavey bravo.....i have done i adjustable cermet on incoming bias this seems to work great 4 matched tubes....schematic in my last post...any help would be mismatched tubes runnin in my bravo......thanks in advance......enzo....steve......help me im from leicester.....

[Enzo]

Welcome to the place. You don;t need to start two threads for this amp, I responded to this in your other thread.

[ampstepper]

hi enzo im pretty confused now...pontiac pete was the only one who responded to my originalpost...he asked for schem 4 bravo ,,i posted schem,,,and in meantime i sussed overall bias mod based on valve king mod... which brings me back to my second post {ever}im lookin 4 independant bias mod 4 each tube,,,,,,iff you responded to this i apolagize but havnt seen your response...im new to actually posting on forums...ive been watching and learning from afar......

[Enzo]

No apology needed, threads don;t cost anything. Just didn;t want to get spread out.

[CharlieP]

What is the need to bias all independantly? Some variation in bias is most likely going to give you a less sterile sound. Perfect bias for each tube is not going to give you perfect tone.

[ampstepper]

yeah i hear ya...but i like the ability to mismatch my tubes to my liking ...but also from past experience there is a lot of people selling supposedly matched pairs and quads that actually are nowhere near sometimes..so i like tha ability tomatch them slighty nearer if you like........

[CharlieP]

Originally Posted by ampstepper

yeah i hear ya...but i like the ability to mismatch my tubes to my liking ...but also from past experience there is a lot of people selling supposedly matched pairs and quads that actually are nowhere near sometimes..so i like tha ability tomatch them slighty nearer if you like........

Sometimes the tone is better with a little mismatch!

[tedmich]

Originally Posted by CharlieP

Sometimes the tone is better with a little mismatch!

quite true, and it might be nice to quantify and reproduce differential bias so some sense can be made of it. My latest Bravo pcb clone has independent bias and 1ohm precision resistors to allow for this! (as well as a cath bypass cap for V2A and a bypass tap for the dual diode noise gate)