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


We recently invested in a Precision Fidelity C7/A and I was thinking of upgrading some of the OEM capacitors. The original designer -- Bruce Moore -- apparently built the preamp. to sound as good as could be in stock configuration without having to modify anything, i.e. evincing the philosophy that an intelligent design should be simple and sound excellent as is.

Has anyone upgraded their Precision Fidelity with caps. such as V-Cap teflons or Auricaps and come away with dramatic differences in sonics, either for the better or worse?

Thank you.
I would like to comment on gsakakeeny's post concerning his claim to have "designed" the Precision Fidelity C7 preamp in 1977 when the company moved to Santa Rosa. I worked for them in San Francisco and Foster City in the late 70's and they didn't move to the business park in Santa Rosa until the Spring of 1980, if I remember correctly. Prior to that I was under the impression that Bruce Moore was the C7 designer, and I had one or more discussions with him that concerned the C7. I was , in fact, the "designer" of the C7a, which was a cluster f___ and turned out to be one of the factors in my exiting the High End Audio business.

Riding on the success of the C7, thanks to glowing reviews which caught our fledgling manufacturing firm quite off guard, Joe Bermudez, who was in charge of Domestic Sales, suggested that we come out with an "upgrade" using polystyrene capacitors instead of polypropylene (or was it the other way around?). We had confirmation of the availability of the new caps and had faceplates made with the new c7a designation, but at the last minute there was some screw up with getting the caps. Joe told me to ship the preamps anyway and we would somehow follow them up with the new caps (when they arrived) with instructions on how to swap them for the old ones. I really don't remember if they ever got to us (it's been almost 40 years...) but we started to get phone calls about how great the "new" modified preamp sounded from our dealers, citing, between gasps, that there was now "depth" and "air" and "transparency" and all the other buzzwords in use at the time. Not a single person complained that the "new" preamp sounded exactly the same as the "old" one, and the accolades about the improved C7 continued to pour in. There were times when Joe, John Fong (the owner and person in charge of International Sales), and I would sit around and read to each other out loud some of the astonishing praises about our C7 being "improved" merely by adding the letter "a" to the faceplate, and laughing hysterically.

Lastly, I hope Mr. Sakakeeny changed the design significantly on the JV1 pre-preamp before he stuck his initials on it - it was my design, as simple as it was...
Just stumbled on this old thread. The Hill Companies did indeed buy Precision Fidelity from John Fong. Since it was my idea the Hill Company's owner handed it to me to manage and grow. I could do neither with it.
Bruce Moore (who I never met) designed the C7 and C7A which were, essentially identical. Gabe Sakakeeny along with Jack Senecal designed the C8 which was a hybrid preamp.
Joe Bermudez was PF's part time sales manager when we bought the company. Joe soon went to work for Mobil Fidelity as PF struggled. John Fong was murdered in Mobile Fidelity's parking lot where he was to meet Joe for lunch as I recall. It was a professional hit--small motor bike and small caliber  hand gun. We handed the company back to Senecal and Sakakeeny and walked away, not so much due to Fong's murder but my inability to make anything viable out of the company.

I purchased a new C-7 and loved it. I sent it in and upgraded to the C-7A.  I liked the original C7A more, especially the variable volume pot as compared to the stepped one on the C-7A   The C-7A then went back to the factory twice under warranty for blown caps. After a third incident, PF offered  me an upgrade to a C-8. I took it.

I preferred the C-7 series to the C8. The remained in service until it smoked many years later. It was brought back to life by Tom Tutay of Transition Audio with an External power supply, great parts and a 12AT7 section.