Fault: volume intermittently louder in one channel

[OllieC]

A problem has reared it's head in my system, whereby after a period of inactivity (say 24 hours), I turn the system on and start to play either music or TV, and the sound is louder in one channel. The sound doesn't completely disappear from the quieter channel, but it is a very noticeable drop in volume. The sound does however always come back to the quieter channel within 10 minutes, bringing the channels back to equal volume. I'm not sure exactly what triggers this - it tends to happen after I've changed sources and turned the volume up a bit, but haven't been able to pinpoint it.

The amp has a buzzing sound that is much more noticeable than when I first bought it, it is audible over moderate volume levels. I have also switched over the cables in the back of the amp during testing and when doing that the problem switches from one channel to the other.

The system has all been bought in the last 6 months:

Amp - Arcam SA20 amp
Speakers - Wharfedale Linton Heritage
Sources - Bluesound Node streamer, Rega Planar 3 turntable
Speaker cable - Chord Company Clearway X

I've contacted Arcam and they've asked me to take the amp to the dealer for inspection. The company I bought the speaker cables from have also said they would take the cables back and test them.

Interested to hear any thoughts/suggestions.

 

[Gray]

...I have also switched over the cables in the back of the amp during testing and when doing that the problem switches from one channel to the other.

Which strongly points to source or source cabling being the culprit.
(You can forget about returning the speaker cables Ollie).
You say the symptom is present on TV and music.....what when both come via Node to Arcam?
In other words, which source gives a problem, Node or TT?

 

[plastic penguin]

A problem has reared it's head in my system, whereby after a period of inactivity (say 24 hours), I turn the system on and start to play either music or TV, and the sound is louder in one channel. The sound doesn't completely disappear from the quieter channel, but it is a very noticeable drop in volume. The sound does however always come back to the quieter channel within 10 minutes, bringing the channels back to equal volume. I'm not sure exactly what triggers this - it tends to happen after I've changed sources and turned the volume up a bit, but haven't been able to pinpoint it.

The amp has a buzzing sound that is much more noticeable than when I first bought it, it is audible over moderate volume levels. I have also switched over the cables in the back of the amp during testing and when doing that the problem switches from one channel to the other.

The system has all been bought in the last 6 months:

Amp - Arcam SA20 amp
Speakers - Wharfedale Linton Heritage
Sources - Bluesound Node streamer, Rega Planar 3 turntable
Speaker cable - Chord Company Clearway X

I've contacted Arcam and they've asked me to take the amp to the dealer for inspection. The company I bought the speaker cables from have also said they would take the cables back and test them.

Interested to hear any thoughts/suggestions.

I had the same with the Leema, only when playing the radio or TV via Sky Box. I narrowed it down to the RCAs. Since replacing those (touch wood) it's been fine.

 

[12th Monkey]

I have also switched over the cables in the back of the amp during testing and when doing that the problem switches from one channel to the other.

Did you change the connection points for the cables at both ends, or just one? If the former and the problem migrates, the cable would appear to be faulty. If just at one, it suggests source, but...

If you've tried different sources and the problem is still there, try connecting to different inputs on the amp just to be sure - but that sounds like cable to me.

 

[OllieC]

Which strongly points to source or source cabling being the culprit.
(You can forget about returning the speaker cables Ollie).
You say the symptom is present on TV and music.....what when both come via Node to Arcam?
In other words, which source gives a problem, Node or TT?

Yeah TV comes via the Node to the Arcam. The problem persists with the turntable too. I’ve realised now that it’s only when I turn the volume up that the sound returns fully to the quiet channel.

 

[OllieC]

Did you change the connection points for the cables at both ends, or just one? If the former and the problem migrates, the cable would appear to be faulty. If just at one, it suggests source, but...

If you've tried different sources and the problem is still there, try connecting to different inputs on the amp just to be sure - but that sounds like cable to me.

The speaker cable was switched just at the amp end. I’ll try different inputs on the amp just to be sure

 

[12th Monkey]

OK - that's not sounding like the cable, then. Sounds like the amp if you have effectively been using one input via the Node. Worth trying others and seeing if the problem is the same.

 

[Gray]

You already know (because you've said) that the symptom is there on more than one source - so you've already confirmed more than one amp input to exhibit the problem.
You swapped speaker cables and it changed sides.
All that and the fact it clears after upping the amp volume, tells us that it can only be the amp at fault.

Do what Arcam suggest and take the amp back to the dealer. It's important that you make it clear to them that the fault is intermittent.
At 6 months old they'll be within their rights to offer you a repair. I would advise that you politely insist on a (brand new) replacement.

 

[OllieC]

You already know (because you've said) that the symptom is there on more than one source - so you've already confirmed more than one amp input to exhibit the problem.
You swapped speaker cables and it changed sides.
All that and the fact it clears after upping the amp volume, tells us that it can only be the amp at fault.

Do what Arcam suggest and take the amp back to the dealer. It's important that you make it clear to them that the fault is intermittent.
At 6 months old they'll be within their rights to offer you a repair. I would advise that you politely insist on a (brand new) replacement.

What I don’t understand is, if the problem switches channels when I swap the speaker cables at the back of the amp, how is the amp at fault? Could it not be a faulty cable? If the amp was at fault, would it not be consistently the same channel at fault despite the cable used?

 

[nopiano]

What I don’t understand is, if the problem switches channels when I swap the speaker cables at the back of the amp, how is the amp at fault? Could it not be a faulty cable? If the amp was at fault, would it not be consistently the same channel at fault despite the cable used?

Because you’re swapping the faulty channel to the other speaker.

This test is on page 1 of tracking down a fault! Sleep on it and the penny will drop.

Cables don’t go wrong. Arcam amps do. That said, what is this buzzing nobody has picked up on? Is it mechanical amplifier noise, or through the speakers? If through the speakers then it’s definitely the amp, though if it only occurs on your turntable then check the connections from your Rega. (Don’t search the other thousands of threads about buzzing Regas, it’ll give you nightmares)

 

[Gray]

....what is this buzzing nobody has picked up on?

I'm lumping that in with the dodgy amp syndrome but you're right, the Rega certainly can't be ruled out.

 

[Gray]

....If the amp was at fault, would it not be consistently the same channel at fault despite the cable used?

Yes it would.
You haven't said which, but let's say, for example, that the left channel of the amp has the problem. So you hear the fault on your left speaker.
If you then swap the speaker cables over, you're feeding your right speaker with the faulty left channel output from the amp.....so now you hear the fault on your right speaker. But the fault is still with the left channel of the amp (which you're now routing to the right speaker, by virtue of swapping the speaker leads).

 

[OllieC]

Aha! Yes the penny has now dropped with the switching of the issue to the other speaker by swapping the speaker cables. Thanks for that.

I'm taking the amp into Sevenoaks this week and will nudge them for a replacement once they've assessed it, assuming that's where the problem lies.

 

[Gray]

I'm taking the amp into Sevenoaks this week and will nudge them for a replacement once they've assessed it, assuming that's where the problem lies.

If the symptoms are as you've described in this thread, the amp is the problem.
Don't forget to tell them that the symptom is present on more than one source
and that it is intermittent.

Let us know....

 

[OllieC]

So the amp has been fixed, picked it up today and all in working order.

I took it into Sevenoaks and they eventually were able to replicate the fault, sent it off to Arcam and they replaced a faulty LS relay (not sure what that is). They couldn't hear a buzzing sound like I could, so they suspect that's to do with mains quality.

Thanks for all your comments, really helpful.