Tube Amps / Music Electronics
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|previous: MBSetzer I did manage to acquire a Defiant w... -- 9/30/2004 3:26 PM||View Thread|
|9/30/2004 8:17 PM|
|R.G.||Re: Thomas Vox help request|
The Defiant/Conqueror/Supreme line is a reverse British invasion. Thomas (I think) managed to convince JMI that the future was solid state. Anyway, that's how the schematic to that particular trio of amps reads.
I worked on a Supreme a ways back and modified it to use a standard reverb tank instead of the ceramic phono cartridge based thingie that came stock. In doing so, I looked the power amp over, and its very reminiscent of the Thomas designs - driver transformer and stacked output stage. The Defiant must be similar.
By the way, the D/C/S series is a dream to work on relative to the Thomas Vox stuff. Neat layout on isolated functionally distinct boards, easy to follow wiring.
The trick to most bipolar amps like these is to get the DC voltages right. First, isolate the power supply and get that working correctly. Then start at the power amp, check voltages and get that right, and open the capacitor leading to its input. Feed a signal and see if it works right. When it does, work backwards toward the preamp. This way you never reach a place where something in earlier stages won't let you know if later stages are working.