Pre-Amp or something else?

Over the course of the last week I’ve had a couple of strange occurrences whilst listening.
About a week ago, I momentarily lost the right channel - everything shifted to the left speaker for about two seconds then righted itself. I don’t think I’ve ever used the balance control more than a handful of times in the 15 years I’ve had the NAC252 but since that happened I’ve felt the right channel was slightly off (in balance) so adjusted it with the remote on a few occasions.
On two of those occasions, one Saturday and one Sunday, I got a sound that reminded me of a spluttering engine and the momentary loss of the right channel again. That prompted me to make sure I talk to my dealer this week - something I was unable to do today due to other commitments, but I’ll certainly do it tomorrow.

However, on sitting down to listen tonight I find that the bass response has pretty much vanished - there is bass at lower mid level but no deep bass. It’s like I’ve lost an octave or more. I’m assuming it’s amplification related as the bass has vanished on phono, cd and tuner. That coupled with the lost channel anomaly makes me thing it’s the pre.
(I ruled out the speakers because when I put the amp in mono and switch the sound to a single speaker they both sound the same and both bass drivers are moving.)

I’ve checked the connections and they all seem to be properly attached.
As far as the amps go, the 252 was serviced by Class A in 2017 while the Supercap DR and the NAP300DR are in the last year of warranty (bought 2017).

In the meantime if anyone has had a similar experience or has any ideas I’d be most grateful to hear them.

I’ve had a channel imbalance on my 252 but put it down to my non symmetrical room… bought some acoustic panels and that have worked wonders…Also had a bass drop occasionally but only when I’ve just started listening… after an hour or two it all seems perfect…

If it’s there on all sources and when you put the pre-amp into mono both channels sound the same then it would appear to indicate a possible issue with the pre-amp. However, it does sound similar to what I experienced a couple of years back. Initially I thought its was the pre-amp, but substituting another showed it was actually the power amp at fault.

I think best to talk with your dealer and see whether you can find a way to narrow it down.

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Thanks Richard I’ll speak with my dealer today.
Really frustrating to have another issue so soon after the loud cracks on vinyl that was resolved just a year ago.

Yes, little niggles can really frustrate.

Spoke to my dealer yesterday and he kindly arranged for me to pick up a 252 and a Supercap to try and identify the problem.

His advice was to try and identify the problem by substituting one piece at a time.

The plan of attack was to use my Burndy and I/C’s with:
His SC, my 252
My SC, his 252.
His 252 & SC.

If not resolved, try his Burndy and I/C’s with:
His 252 & SC
His SC, my 252
My SC, his 252
My 252 & SC

If none of those combos work it’s likely the NAP300DR.

Thankfully as soon as the SC went in the bass was back.

So once again, big thanks to Rob at Adventures in Chester for helping me out of a sticky situation. Just goes to show how important a good dealer is.


Great stuff. Saved a lot of head scratching and frustration, I’m sure.

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