Author Topic: some more model t questions  (Read 2662 times)

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Offline Ryanx

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some more model t questions
« on: January 04, 2008, 08:07:42 pm »
so in attempts to tinker with my amplifier in search of the perfect sound i come up with a few questions to start. 


what's a typical bias setting for the original model t.  i have reason to believe i might be running "hot" but i'm not sure.  i really don't want to screw around with that stuff so i don't blow my head but i know that the "setting" the previous user had it running at was something like "55", it's penned on the inside right next to the bias pot.  also what tool will i need to bias my amp, typical biasing tools?


second, the phase inverter is in deed the spot that "stands alone" correct?  i'm throwing a 12at7 in there to clean up my preamp section, just wondering.  should i buy 2 more at7's and run my entire preamp with them?

Offline mckinnon audio

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Re: some more model t questions
« Reply #1 on: January 05, 2008, 03:03:04 pm »
  Hi there,I believe the T runs at -55 vdc for bias.To adjust it you need a volt meter,small screwdriver and a little bit of knowledge.What's important here is plate current draw,you might want to invest or make your bias probe to measure plate current on your output tubes.If you replace 12AX7A's with 12AT7's you'll get less gain.The ax's are hi gain,the at's are lower,good luck Mel.