Tube Amp Archive

Resolved. Was a bung JJ out of the box, one of them had intermitant shorts. Bias voltage would sit at 35mA or so and then sky rocket to over 200mA and redplate up a storm. Replaced the power tubes and bingo shes away singing.

If the choke is attached to the chassis with metal screws it should be at the same potential. I agree, there should be 12v on the chassis as well if this is truly the case. TM Hey thanks guys for the quick follow up, havent had a chance to re-investigate this tonight, will try tomorrow evening and ...

wondering if anyone has ever come across voltage on the choke frame/casing? Ive got this really weird issue, popping from speaker, and it changes tone. powered up a new hrm build a week or so ago, bulb limiter test was fine, tubes in voltages look ok, slightly hot but well within a 10% range. Contin...