This is my personal project: Low Cost 2+2 W tube stereo Amplifier @ 60Vcc
This amplifier uses two tubes per channel: PL504 (EL504) and ECC82.
The performances are very good in spite of such a low unconventional supply voltage.
The output Audio Transformer is 800/8 ohm impedance, but if you accept a little bit lower bandwidth (low frequency cut < 100 Hz ), you can use line transformer 220/24 Vac (not less than 35W to avoid dc saturation).
Note: in all my prototypes I used line transformers as output transformers.
The above schematics is for one channel, uses two triodes preamp (common cathode and cathode follower).
The supply voltage of 60Vcc is achieved using a diode voltage doubler and a 15+15Vac Line transformer.
(stereo) version with just one triode preamp per channel and without the diode voltage doubler (transformer @ 48Vac).
In this version I used EL504 (6.3 V filament) instead of PL504 (27 V filament).
- Protototype 1:
- Prototype 2: MP3 Tube Stereo Amplifier
-Prototype 3: Stereo Amp with line transformers used as output transformers
- Test: Stereo Amp with line transformers used as output transformers
Edited by pilovis - 3/6/12 at 9:08am