I am the very lucky new owner of an almost-40-year-old CJ P3 valve pre-amp.
I really like the look and feel of it, and I love the sound!
It honestly is everything I have always wanted from a pre-amp to drive my various valve power amps.
I do, however, have 3 questions about this pre-amp.
(I do the have very basic CJ user manual, which does not seem to answer my questions).
1. What does the MODE switch do?
On Phono input (the only way I am using the pre) I usually have the MODE set to STEREO.
However, turning it to Left or Right makes no difference (both channels still play) and REVERSE also does not seem to make a difference.
Only MONO changes the sound a little (for the worse, on a stereo LP.)
2. Phase Invert?
I have read that the P3 is a phase-inverting pre-amp.
But this seems to be only on line-level inputs - so not PHONO input?
Does this then mean I have to switch my Red/Black speaker connections "the wrong way" round for line-level inputs but not for PHONO input?
I am sure I am missing something here?
3. One channel "acting up"?
Usually - like right now - the amp plays perfectly.
However, every now and then, the one channel goes very soft / has buzzing and distortion coming through the speaker.
Always the same channel.
A. I first suspected a valve mono block issue, so switched them around. This moved the problem to the other mono block/speaker.
B. I then suspected the one (L) RCA cable (Jones plug to RCA for my Quad II amps), and swapped that out for another cable. Things immediately sounded 100%. This made me think I have solved the problem...
C. Then, at the start of my next listening session, it happened again - on the same pre-amp channel, where I was now using a "new" RCA cable. I unplugged the cable, and then plugged it back in again, and the problem went away. Right now still playing perfectly.
What could my problem be here? Maybe a dodgy RCA L-channel "OUT" on the pre? Or what else, given my description of the problem?
What other tests could/should I do?
Unplugging and re-plugging the Jones/RCA cable seems to sort out the issue every time?
Playing as perfectly as it is right now, I cannot believe there is a real issue (valve / cap / etc.) with my pre. But what could it be?
As always, all advice / comments will be greatly appreciated. Especially from anyone who has owned one of these beauties!
Thanks,
Johan
I really like the look and feel of it, and I love the sound!
It honestly is everything I have always wanted from a pre-amp to drive my various valve power amps.
I do, however, have 3 questions about this pre-amp.
(I do the have very basic CJ user manual, which does not seem to answer my questions).
1. What does the MODE switch do?
On Phono input (the only way I am using the pre) I usually have the MODE set to STEREO.
However, turning it to Left or Right makes no difference (both channels still play) and REVERSE also does not seem to make a difference.
Only MONO changes the sound a little (for the worse, on a stereo LP.)
2. Phase Invert?
I have read that the P3 is a phase-inverting pre-amp.
But this seems to be only on line-level inputs - so not PHONO input?
Does this then mean I have to switch my Red/Black speaker connections "the wrong way" round for line-level inputs but not for PHONO input?
I am sure I am missing something here?
3. One channel "acting up"?
Usually - like right now - the amp plays perfectly.
However, every now and then, the one channel goes very soft / has buzzing and distortion coming through the speaker.
Always the same channel.
A. I first suspected a valve mono block issue, so switched them around. This moved the problem to the other mono block/speaker.
B. I then suspected the one (L) RCA cable (Jones plug to RCA for my Quad II amps), and swapped that out for another cable. Things immediately sounded 100%. This made me think I have solved the problem...
C. Then, at the start of my next listening session, it happened again - on the same pre-amp channel, where I was now using a "new" RCA cable. I unplugged the cable, and then plugged it back in again, and the problem went away. Right now still playing perfectly.
What could my problem be here? Maybe a dodgy RCA L-channel "OUT" on the pre? Or what else, given my description of the problem?
What other tests could/should I do?
Unplugging and re-plugging the Jones/RCA cable seems to sort out the issue every time?
Playing as perfectly as it is right now, I cannot believe there is a real issue (valve / cap / etc.) with my pre. But what could it be?
As always, all advice / comments will be greatly appreciated. Especially from anyone who has owned one of these beauties!
Thanks,
Johan
