Saturday, May 31, 2014

Designing an all-tube push pull stand-alone reverb unit

I finally fulfilled a long-time dream of mine and I built my own all-tube guitar amp. It is a 15-watt clone of a Matchless HC-30. The kit was purchased from Trinity Amps. It sounds phenomenal. It does not have any reverb though, so I set out to build a stand-alone reverb unit. I did not want to do the obligatory Fender 6G15 for no other reason than just to be different.

After a lot of research, I made this design based on the Firefly by Doug H. (see and the stand-alone reverb design in Kevin O'Connor's book "Tonnes of Tone" (see

Version 1.0:

Wasn't quite "there." After my initial observations and some feedback from the fine folks at and Trinity Amps ( - you MUST check them out if you are at all interested in building your own tube guitar amp from a kit) I made some changes and improved things.

Version 1.1:

This brightened it up a bit and took care of some nasty red-plating of the 12AT7. Sounds a lot better and the tube no longer burns my fingers to the touch. I still think it could be better though. I am still experiencing some hum - probably because of my inexperience with layout. You can post comments here if you have ideas for improvement,  or over on the forums at and I have some threads where we are discussing this.

Next thing I will probably try is changing the cathode resistor from 1k5 to 1K.

The unit on my workbench:

The unit on top of my TC15 build and my TS-808 clone I built:

No comments:

Post a Comment