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Fender bassman 300 Pro Bias question Need to know if it is safe to use

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Nighttrain1127:
 What would you say the bias voltage should be set at .  I don't really want to cook the tubes that I just got. Any suggestions?  It does seem to be running pretty hot right now.

Nighttrain1127:
OK just for general Knowledge Fender Now recommends Biasing the 300PRO the same as the Super Bassman 300 at 80mV.  Thanks for the information that led me to search out the answer Guys.

amptech:
There you go then, your amp is biased by monitoring cathode current. You actually measure current, by taking the read across a resistor between the catode and ground. This resistor 'translates' your mV reading so to speak, it's a terrific and easy way to monitor bias in theory.

Unfortunately, as PBG said, many things can go wrong when you monitor current constantly - amp manufacturers stick too many components between cathode and ground, somewhere on the PCB, and they increase the number of things that can go wrong.
Of course, all sorts of thing can go wrong in an amplifier, but any design feature that can lead to your amp losing bias should be avoided. I've had quite  a few amps on the bench the last years with these kind of issues.   

Nighttrain1127:
You guys are very helpful. It is nice to have a different Forum to ask questions and get straight answers . 

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