Precision Fidelity C7/A: To modify or leave as is?

Thanks for the response Richard. This piece is in fact the "C7/A Revised," as I recall printed on the circuit board. I think it is a monument to fine, fine engineering bar none but the perhaps a handful of other preamps. Thank you.

As I recall, your unit is a couple of decades old.
I had a Precision Fidelity, but a lesser model and it was a very decent sounding unit.
Simple design,dual volume or balance knobs and I think a couple of tubes, but a big open sound.
I should have kept it.
If I would have, considering it's age, I would at least have all the caps and resistors checked out and replace the ones that need to be replaced with better ones.
I would also try to find out where in the circuit that a cap upgrade would yield the best results.
This is where a good tech is invaluable if you can't do it yourself.

Pardon my initial comment that the Precision Fidelity C7/A Revised is "a monument to fine engineering bar none but perhaps few other preamps." Rather, a more appropriate and balanced statement would be that it is "a monument to the finest of engineering bar none given phonocentric systems."

Does anyone know if the C7A "modified" different than the "revised"? and, where the modified and revised versions silkscreened with "C7A Revised" on the back of them or was it just an internal change with the "C7" on the back?

thanks

Just for the record, the original C7 was designed by me when Precision Fidelity had just moved to Santa Rosa, CA in 1977. The company was sold to The Hill Group, a holding company in San Diego in 1978. They eventually sold the designs to Bruce Moore who ran the technical end after that. I went to National Controls to design A/D convertors and exited the audio scene.

I'm delighted that the C7 and the M80 stereo power amp have become such beloved instruments. As an technically inclined artist, it is satisfying to know that my creations have provided so much pleasure for so long.