1. Why?  Because it is wrong.  Tubes and surround sound do not mix.

  2. Vacuum tube home theater sound system

  3. Built in my garage and basement

  4. 23 tubes total

  5. 5 class AB vacuum tube audio power amplifiers

  6. One mono-block amplifier:  Mono-Block Tube Amplifier

  7. One quad amplifier:  Quad Tube Amplifier

  8. EL34 output tubes

  9. Each amplifier is over 400 watts peak output power

  10. 0.45% THD

  11. 20 Hz to 25 KHz -3 dB bandwidth

  12. 6 channel vacuum tube pre-amp/multiplexer

  13. The following information is provided:

  14. Summary

  15. Photos

  16. Engineering notes and schematics


This is a good example of a project that has become completely out of control.  At some point in the past I decided to build an all-tube home theater system (except for the DSP stuff that decodes the various Dolby 5.1, and etc signals).  The result of this effort is affectionately known as "Frankenstein." It consists of 5 class AB tube power amplifiers, tube pre-amps, and a Dolby 5.1/DTS digital signal processor, for a total of 27 vacuum tubes.  Each power amplifier is capable of over 400 watts peak output. All of the equipment is mounted in a 7' tall WW2 vintage equipment rack.


G. L. Charvat, “Vacuum tube home theater system (part 2), vacuum tube power amps for home theater,” Audio Express Magazine, June 2012.

G. L. Charvat, “Vacuum tube home theater system architecture, a “monster” system uses 23 vacuum tubes,” Audio Express Magazine, May 2012.

  1. G. L. Charvat.  “Design and fabrication of high-fidelity vacuum tube audio-frequency power amplifiers,”  MIT Haystack Observatory, February 3, 2010.


B. Benchoff, ‘Frankenstein, an all-tube home theater amplifier,’ January 2, 2012.


  1. Make Magazine Blog, ‘Frankenstein, an all-tube home theater system.’

Engineering Notes and Schematics

Caution!  High voltage.  Do not attempt to build anything shown here unless you have taken proper high voltage training.  The high voltages present in these tube designs are deadly.

Power distribution notes

Surround pre-amplifier and switch matrix notes


Frankenstein, a vacuum tube home theater system

Photo albums:


Mono-block tube amplifier

Quad tube amplifier


System block diagram

Callouts for block diagram

Transfer switch and preamplifier schematic

Power distribution schematic

Mono-block tube amplifier

Quad tube amplifier