• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

5.1 channel 807 SE amplifier

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I just finished my project after a few months of planning/assembly but mostly waiting for parts to arrive in mail. Decided to share.

Design:
The amplifier has five 807 pentodes running in single-ended fixed bias with Edcor GXSE10-8-5k output transformers. the pentodes are driven by 12AT7's. in addition, i have made use of 12AU7's as pre-amplifiers for all 5 channels, plus a sub-woofer pre-amp for a external solid state amplifier. I am making use of an 5C8S rectifier tube for the 320ma of current required for powering so many channels. The power transformer is a Antek AN-4T400 which is rated for 400VA. The VR-105 tubes are wired in series and used to provide regulated power for grid 2 on the pentodes. Filaments are powered by a modified random pc power supply i tweaked to provide 12.6v

Pictures:
I have pictures i have taken as i built it. Can take more pictures/better pictures of certain parts if people are interested. more pictures can be found at:
ryuji's pictures

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.


Schematics:
I used multiple schematics to build the amplifier:
Power tube design:
An externally hosted image should be here but it was not working when we last tested it.

Pre amp:
An externally hosted image should be here but it was not working when we last tested it.

Bias supply:
An externally hosted image should be here but it was not working when we last tested it.


Additional information about anything available by request
 
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