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sootshe 31st January 2011 09:26 PM

CJ PV-15 Pre
 
I have a problem with the balance in my CJ PV-15 pre. The left channel is consistently 2 notches louder than the right on the digital display indicator.

I've changed the valves & tried different combinations of valves to try to balance things out, but nothing seems to change the imbalance.

My dealer says that the balance is totally dependant on the valves used & says to just listen with the balance controls adjusted accordingly. When I do this, the sound is spot on, but it feels a bit strange to see the level indicators at different positions.

Is it possible to recalibrate the level indicators to account for this imbalance?

BTW, the replacement valves are originals as supplied by CJ.

Many thanks,
John:confused:

SY 31st January 2011 09:35 PM

Has it always been that way? Or is that a problem it developed over time?

sootshe 31st January 2011 09:45 PM

Quote:

Originally Posted by SY (Post 2453100)
Has it always been that way? Or is that a problem it developed over time?

I bought this unit as a used item with warranty & yes, it's pretty much been like this all the time. When I first bought it, it was noisy in 1 channel & had the slight imbalance & I immediately ordered some new valves to go in it. These have taken some 6 months to arrive (due to the dealer delay, not CJ) & I was hoping this would cure the problem. The unit now sounds great & is almost silent, but the channel imbalance remains.

My dealer has told me that the channel balance is totally dependant on the valves & that is why the balance control is there - to even out any discrepencies. I'm just finding it hard to come to terms with the left channel showing 34 & the right showing 36!!!

SY 31st January 2011 10:12 PM

If you switch the tubes (left to right), does the balance change? If not, your dealer is incorrect (most hifi salesmen are not terribly conversant with the intricacies of electronic design). You may have some defective components in one channel, you may have a poorly tracking volume or balance control.

If the balance changes with tube swap, get some new tubes.

sootshe 31st January 2011 10:33 PM

Quote:

Originally Posted by SY (Post 2453128)
If you switch the tubes (left to right), does the balance change? If not, your dealer is incorrect (most hifi salesmen are not terribly conversant with the intricacies of electronic design). You may have some defective components in one channel, you may have a poorly tracking volume or balance control.

If the balance changes with tube swap, get some new tubes.

No, the balance stays just the same, even if I swap the valves left to right, or in fact, try other combinations of different valves left to right.
Looks like I need to contact CJ direct for some help.

Thanks for your input,
John

SY 31st January 2011 10:36 PM

Yeah, there's no reason that a preamp with a comma in the pricetag should perform a basic function worse than a $200 mass market receiver.

machine_head_69 8th February 2011 08:06 PM

I have the same preamp, I would suggest giving Ed at CJ a call, he is in the service dept. and a real nice guy, maybe a setting, or a problem in the board.


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