A small single-ended tube amplifier project that uses the 6T9 compactron vacuum tube. This tube amplifier project has been constructed using a purchased PCB and for the enclosure Mark has used an inexpensive baking pan. The small amplifier only produces a few Watts of output power, but Mark reports very good results with a pair of high efficiency speakers
Mark had increased the input and coupling capacitors to 0.22 uF and used polypropylene types. These components are physically larger than what is meant for the PCB so some manipulation is required. He also liked to use snubber capacitors across any possible noisy components such as 0.01 uF poly caps. across the diodes and 1 uF capacitors across the filaments of the valves. Snubbers on the filtering caps is also a good idea and he used 0.1 uF polies. He added an extra 200 uF of capacitance to the power supply and found that this helped the bass response. He used a Hammond 369JX power transformer and Edcor XSE15-8-5K for the output transformers (OT). A smaller OT can be used but expect the bass and treble to suffer. The Edcor OTs are very reasonably priced and also have a ultra-linear (UL) tap so you can run the amp in true UL mode.
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