Vermes
Advanced Member level 4
It is an acoustic tube amplifier based on popular and easily available tubes ECC83 and EL84.
This is a full-tube amplifier. The „Push Pull” name is from the contralateral system. Tubes used are dio triodes of small power – ECC83 (control) and power stage implemented on power pentodes – two EL84 tubes per channel. Signal from their output is summed at the anode detach of the speaker transformer (Raa=10k). The right transmission on the secondary side of the transformer (8ohm) causes that the signal is adapted to the speakers with a low impedance of the coil.
Housing is in retro style: it has pinewood sides and a mirror, in which glowing tubes reflect. Bottom is made of 5mm aluminum sheet. The supply transformer, another sheet with speakers transformers, PCB and sides of the amplifier are attached to that bottom.
Front panel was made of 3mm thick aluminum. There is a switch, IR receiver, switches with LEDs (selection of the channel) and ALPS potentiometer with a motor.
Back consists of supply socket, nameplate, three stereo inputs on chinches and outputs, where you can use banana plugs.
Top is 1mm thick sheet with cut holes for the tubes and a can (cover for the speaker transformers) made of laminate.
The whole device is easy to disassemble or eventual modifications.
Power supply – the transformer needs to be rewinded as the tubes are glowed by the AC. Anode voltage in the system is about 300V and its switched after approximately 30 seconds from starting the amplifier (which prolongs the life of tubes).
Audio board consists of two independent channels on a single PCB. It is placed just under the top plate. Bigger components such as capacitors weer soldered lying or from the bottom. You can adjust the current of tubes nets polarization using trimmers.
You can learn more about the Author of that project on:
**broken link removed**
Link to original thread - Wzmacniacz lampowy Push Pull ECC83, EL84
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