biasing and old power tubes etc.

Tubes Asylum

Questions about tubes and gear that glows. FAQ

If the bias of an old power tube dips below recommended levels, is it the 'norm' to increase bias on the power amp until it reaches the optimum setting? And we keep doing this until the tube gives up the ghost?
The instruction manual of the Quicksilver GE 8417 mono amp states that bias should be set at 110 and 120mA. But for some reason not made known to me (unfortunately), the previous owner of my Quicksilver GE 8417 left instructions that bias should not exceed 45mA.
Can someone second guess him on the reason for this 45mA limit? Can it be changed? (And in case you are wondering, previous owner can no longer be reached).
Many thanks, again, guys.
raz

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Topic - biasing and old power tubes etc. - razzwill@gmail.com 20:54:14 02/06/07 (6)

Re: biasing and old power tubes etc. - Tom Bavis 11:06:21 02/07/07 (0)

Re: biasing and old power tubes etc. - Catch22 21:53:55 02/06/07 (2)

Re: biasing and old power tubes etc. - Rob Mercure 08:08:53 02/08/07 (0)

Re: biasing and old power tubes etc. - razzwill@gmail.com 06:57:50 02/07/07 (0)

Re: biasing and old power tubes etc. - beermanpete@socal.rr.com 21:51:17 02/06/07 (1)

He converted a number of those amps - Frihed89 02:19:58 02/07/07 (0)

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