Distortion From My 2-channel System

[GO-NAD!]

And few days ago, was listening to Allegri's Miserere on CD and I heard intermittent distortion from the speakers. It seemed to be coming from the left channel, but I wasn't completely sure, as it was so intermittent it was it difficult to isolate it while using the balance control. It sounded kinda like static. Yesterday, I swapped around the Studio 20's to see if it was the speaker, but when I listened to a couple of CD's to check, the distortion didn't make an appearance at all. This evening I'm listening to a couple of CD's, including the Miserere piece and I heard the distortion just once, for a couple of seconds, which wasn't enough to determine which speaker it was coming from, or if it was from both.

So, what's the likelihood that this could be a speaker problem, or further upstream in the amp, CD player or DCX? I would think that if it was speaker-related, it would be consistent, while a problem with the electronic end could come and go. I suspect that I may have to wait for the problem to manifest itself more consistently in order to track down the source.

Any ideas?

 

[PENG]

I m not familiar with the NAD C372 but if it is an older amp with analog volume control then it sounds like a typical thing due to carbon dust accumulation on the volume control rheostat and it would typically sound like static when you play with the knob but it could also do it even without you turning the knob.

 

[GO-NAD!]

I m not familiar with the NAD C372 but if it is an older amp with analog volume control then it sounds like a typical thing due to carbon dust accumulation on the volume control rheostat and it would typically sound like static when you play with the knob but it could also do it even without you turning the knob.

It does have a rotating volume knob, but I've never had it happen while changing volume. If that ends up being the problem, is it easy to clean? Oh, and thanks for the quick response. I'm on the third CD now, and it hasn't happened again. Puzzling....

 

[PENG]

It does have a rotating volume knob, but I've never had it happen while changing volume. If that ends up being the problem, is it easy to clean? Oh, and thanks for the quick response. I'm on the third CD now, and it hasn't happened again. Puzzling....

I had to do that on a 35 years old Marantz preamp recently and it was not difficult at all. In your case I agree with you that you may have to wait until the problem become more consistent. It is very difficult to try and pin point the root cause when it happened only once.

 

[GO-NAD!]

Well, the problem certainly didn't go away by itself. It seems to be happening more often lately when I listen to a CD. Plus - and this may be completely unrelated - quite often, when listening to the radio tuner, there are intermittent volume drops. It'll last a few seconds and return to the set volume. Sometimes it doesn't happen at all. It never happens when listening to CD's though. I don't stream through Bluetooth very often, but I don't recall either phenomenon happening then. Puzzling and irritating. Since the problems are different and dependent on the source I'm listening too, I can't be certain it's an amplifier problem. There could be coincidental issues with a CD player and the tuner.

 

[GO-NAD!]

SONOFA.....! I'm relieved and pi$$ed at the same time. The girls are out and I found some time to do some further investigation. Just to backtrack a bit, the other day, I disconnected the CD players and tried an old DVD player to see if that was the root of the problem. I didn't think it would be and I was right. I got the same distortion. This evening, I decided to change the inputs for the CD player - yeah, I was grasping at straws. Anyway, after I changed the CD interconnects to "disc", I selected that input on the front panel and then noticed that the tone control button was engaged and the treble knob was turned all the way up! All along, it seemed to me that the distortion seemed to be in the higher frequencies, but I believe my hearing is degraded in the upper ranges, so I wasn't sure. I turned the treble back to the middle position and disengaged the tone control.

I held my breath and tried the same Miserere CD that I was playing when I first noticed the distortion. Miraculously, the distortion was gone! I had never heard the distortion while listening to the FM tuner - at least I hadn't noticed it before. Could that be because of the limited frequency range of FM - relative to CD, that is?

I know I'll never find out who had messed with the tone controls. My wife and daughter wouldn't have touched them, but we have several small nieces and nephews who visit frequently. I suspect one of them of playing with buttons. I'll try a couple more CD's before I put this issue to bed, but I think I'm good to go.

 

[markw]

The audio gremlins do it at night just to pith you off.