I was way overdue for replacing the tubes in my PV12A which I bought new in 1998. Previously I've had a local upscale audio shop replace the tubes and check for any problems, of which there were none. This time, I thought I might replace the tubes myself.
Knowing which model of tubes but not knowing which brand of tubes C-J used originally, I set out to research the type of tubes needed from several online vacuum tube retailers. This quickly became a fools errand as the description/comments for the various tubes were not in sync. So, I called C-J and was able to get which brand of tube they use in their PV12A replacement set. To be honest, I was skeptical but had faith that they actually listen (as they claim). I bought the brands of tubes that they use which are:
- V4 V5 V6 JAN Philips 5814A
Upon the completion of replacing the tubes, I reconnected the PV12A to the sources and Premier 11A amp and played one of my favorite CD's: I was devastated. It sounded awful, worse than a low-end garden variety receiver. I changed the source CD to one that had typically been one of the warmer sounding recordings and the sound was still harsh. What the ....? I've read in several audio forums that preamp tubes do not require a break-in, but I decided to check for myself. Sure enough, after about 10 hours the PV12A made a 180°change and went from awful to unbelievably detailed
with a very notable higher gain and deep bass extension. Additionally, the sound stage became deeper, though not as wide. Quite frankly, the PV12A never sounded this good (and nothing else in my system has changed).
I would recommend using the C-J brands for tube replacement.