Presenting the "Harmless" stereo amplifier project, the great-sounding stereo amplifier harmless to tube guitar amp builders.

Guitar players know where to go for the best sound - tubes.   Sixty years after transistors supposedly killed tubes off, tubes are still with us, and still producing the best guitar tone.   This is not likely to change.   Ever.   But when it comes to listening to music in the tube amp workshop, it's not tubes, but transistorized amplifiers pushing tunes to amp builders' ears.   Why?   Simply put, tube-type hi-fi audiophiles and tube guitar amplifier aficionados are in camps with mutually exclusive goals and they rarely interact.   One has extreme fidelity as the goal, and one intentionally fosters different kinds of distortion for the pleasing musical sounds it produces.
Harmless' features: "Harmless" schematic, circuit board layout, component hookup, and drilling template, Rev. 0
"Harmless" schematic, circuit board layout, component hookup, and drilling template, Rev. 1
"Harmless" Bill Of Materials

Rev 0 and Rev 1 differ only in the selection and layout of the transformers and choke.   Rev 0 is for a Z-axis power transformer and the updated Champ output transformers.   Rev 1 is for an X-axis power transformer and upgraded, Edcor output transformers.

"Harmless" project progress:
- Breadboard, monaural "test bed" version was in use for months using various output transformers and tone circuit tweaks without a hitch.
- Beta stereo version is completed and in service.  Photo progress: Feedback is appreciated, I want to hear from you!   If you are an AX84 member, feel free to post a new thread with your thoughts in the General Homebrew Discussion forum.   If you are not an AX84 member, you may contact me via the eMail link below, but please consider joining AX84 to share your thoughts with other home amp builders.

Please use AX84 forums for Harmless discussion.  For contact about this site: