Battery powered tube amplifier using russian tubes 1J24B and 1J29B. Two Li-Ion batteries are used to provide enough voltage for the filament series arrangement and to supply the MAX1771 SMPS which boosts the 7.4V to 100V for the plates. The heater wiring only requires 35mA of current. The output stage is in Push-pull, driven by a paraphase PI. The total output is 0.3W , which is quite loud to play in a living room. Nice practice amplifier with lots of gain and distortion. The 4″ speaker works nice in this 180x180x80mm box, from an old ammeter.









