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previous: Doc Re: Doc -- 9/23/1998 10:36 AM

Triode Bias Pot/Dumble Thoughts

9/23/1998 3:59 PM
cbs	Triode Bias Pot/Dumble Thoughts Doc, How about a variable bias pot on a triode grid leak resister, you could raise the peek of the audio signal to the clipping voltage for the tube? I read a Howard Dumble article in Guitar Player magazine back in the early 80's (I remember a picture of Christopher Cross and Dumble in the article). I remember Dumble saying he didn't use high gain stages, also that the component spacing and circuit constants were critical. He said that he began using Fender chassis's but he had to redrill all the mounting holes to reposition components. He also said you couldn't look at the circuit and find his "tone secrets". But, anyway without using high gain stages couldn't you get distortion by varing a triodes bias setting ? Could this be the "Ratio" control on a Dumble? Additionally, could the circuit constants (mutual inductive/capacitive coupled components and wiring) be a positive feedback complementing the negitive feedback for a balance on the edge between stable and unstable? The balancing on the edge of multiple resonance frequencies would yield a amplifier that is almost analogous to a electrical "musical instrument". I remember a few years back (23 yrs) being in a music store, the owner had just restrung, tuned, and hung 50 or so acoustic guitars, when I played an electric, not very loud, the whole room seemed to fill with sound, the guitar/ rig sound amazing. Then we realized all the acoustics on the walls were "singing along". Wouldn't this be similiar to a resonant amp? Just some random thoughts,CBS

9/23/1998 3:59 PM

cbs

Triode Bias Pot/Dumble Thoughts

Doc,
How about a variable bias pot on a triode grid leak resister, you could raise the peek of the audio signal to the clipping voltage for the tube?
I read a Howard Dumble article in Guitar Player magazine back in the early 80's (I remember a picture of Christopher Cross and Dumble in the article). I remember Dumble saying he didn't use high gain stages, also that the component spacing and circuit constants were critical. He said that he began using Fender chassis's but he had to redrill all the mounting holes to reposition components. He also said you couldn't look at the circuit and find his "tone secrets".
But, anyway without using high gain stages couldn't you get distortion by varing a triodes bias setting ? Could this be the "Ratio" control on a Dumble?
Additionally, could the circuit constants (mutual inductive/capacitive coupled components and wiring) be a positive feedback complementing the negitive feedback for a balance on the edge between stable and unstable? The balancing on the edge of multiple resonance frequencies would yield a amplifier that is almost analogous to a electrical "musical instrument". I remember a few years back (23 yrs) being in a music store, the owner had just restrung, tuned, and hung 50 or so acoustic guitars, when I played an electric, not very loud, the whole room seemed to fill with sound, the guitar/ rig sound amazing. Then we realized all the acoustics on the walls were "singing along". Wouldn't this be similiar to a resonant amp?

Just some random thoughts,CBS

Replies:

cbs Re: Doc Triode Bias Pot/Dumble Thoughts -- 9/25/1998 7:51 AM
Doc Re: Triode Bias Pot/Dumble Thoughts -- 9/28/1998 2:08 PM