I collect direct heating triodes for fun and later found they are very good for single end audio power amplifiers.
I’d like to test different output tubes so I build a stereo single end experiment platform to facilitate them.
The concept is simple, I use independent power supplies:
1. 0-1200V 450ma DC variable to fit power tube (high voltage dangerous)
2. 0-450V DC variable to fit voltage amplifier tube
3. 0-100V DC variable for grid fixed bias.
4. 0-12V DC 15A x2 filament supply
Power supply tower with military grade high voltage filter capacitor bank (see pictures below).
Easily change the tube socket arrangement that fits different input-output tubes and stage block module board covered with studs for point to point wiring so that circuit modification or component change becomes easy (see pictures below).
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The output tube connection is simple but different tube will give a different sound. The voltage amplifier arrangement has many choice such as SRPP, Cathode follower Direct couple, RC couple or transformer couple. I will try them one by one to see the results.
Thank you for visiting!