I have finally boxed my Raspberry Pi controlled P-P amplifier. It ended up rather monstrous!
All metal sheet was hand beaten into submission. No a single laser cut to be found in this construction.
Summary:
P-P output stage using toroidal OPT
Bias monitored & controlled by the RPi
Takes a range of power tubes (6550, KT88, 6L6, EL34 etc), the Rpi makes the bias adjustments as set from front panel (25-90mA)
B+ approx 400V
Driver is Pete Millet's P-P driver boards
Tone control is Braxandall. Can be switched off & out of the circuit via the front panel.
Pout = 40W RMS into 8 Ohm (visible distortion on scope)
Distortion at 2W is approx 0.1% (2nd & 3rd harmonic)
All metal sheet was hand beaten into submission. No a single laser cut to be found in this construction.
Summary:
P-P output stage using toroidal OPT
Bias monitored & controlled by the RPi
Takes a range of power tubes (6550, KT88, 6L6, EL34 etc), the Rpi makes the bias adjustments as set from front panel (25-90mA)
B+ approx 400V
Driver is Pete Millet's P-P driver boards
Tone control is Braxandall. Can be switched off & out of the circuit via the front panel.
Pout = 40W RMS into 8 Ohm (visible distortion on scope)
Distortion at 2W is approx 0.1% (2nd & 3rd harmonic)