Skip to main content
Topic: Loss of sound in one channel (Read 2192 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Loss of sound in one channel

Hi all,

Recently purchased some new Tannoy Revolution XT6F speakers and since then have been experiencing a weird issue with my setup. The speakers are driven by a Cambridge Audio 640A, with two sources: a Chromecast audio, and a little CYP dac connected to my TV's optical out.

Intermittently, one channel will go extremely quiet, and slightly crackly. Perturbing the cables on either end does not alter the sound at all, neither does fiddling with the RCA input connections. I've tried disconnecting the source at the other end - i.e. removing the 3.5mm jack from the Chromecast audio - and then reconnecting it, but the problem persists. What fixes it is flipping the input selection to another source, then back again. On switching back, the balance has returned and sound is coming out of both channels as expected. One other thing to mention is that I THINK - I can't be any more certain than that because I've only just started to keep a log of the issue - it has happened to both channels (just not at the same time).

I have a physics background, but certainly not electronics :P I have discussed it with a colleague at work who is a lot more knowledgeable in this area than myself and he suggested there might be a problem with the power stage, although he thought it was strange that both channels have been independently affected since they have independent power amps. The amp is probably around 10 years old (possibly even older), so we also discussed that the caps might be reaching the end of their life and could probably be fairly easily replaced. I'm more than happy to get the soldering iron out if I have to!

Does this sound like a plausible explanation to anyone here, or has anyone experienced a similar issue with an alternative cause? I am conscious that this problem appears to have only surfaced upon the addition of the new speakers, but the fact that the input switching provides temporary relief would seem to suggest the speakers themselves are not the cause....

Any help anyone can provide would be much appreciated! Thanks.

Re: Loss of sound in one channel

Reply #1
What fixes it is flipping the input selection to another source, then back again. On switching back, the balance has returned and sound is coming out of both channels as expected.

Would this suggest that the input switch could benefit from cleaning? For example with some of this:

http://uk.farnell.com/servisol/super-servisol-10/cleaner-switch-contact-200ml/dp/278786

Re: Loss of sound in one channel

Reply #2
Indeed, I have what could be described as the same problem with an old (+20year old) integrated amplifier.

As in your case, the cables don't seem to be the problem, but when changing the source input with the selector, it somehow fixes.
What is a bit more strange is that sometimes, just pressing the amplifier case in some specific parts, fixes it too.  I tried to remove the case some years ago but I couldn't, (weird screws and strongly tied). Else, I would have checked if it was some soldering issue or really just some contact cleaning.

Re: Loss of sound in one channel

Reply #3
Have you a different input on your amp that you can use? It sounds like, as finphil said, that it might be a dirty contact in the input switch.

 

Re: Loss of sound in one channel

Reply #4
What fixes it is flipping the input selection to another source, then back again. On switching back, the balance has returned and sound is coming out of both channels as expected.

Would this suggest that the input switch could benefit from cleaning? For example with some of this:

http://uk.farnell.com/servisol/super-servisol-10/cleaner-switch-contact-200ml/dp/278786

Many thanks! Just been chatting with another friend at work (also a Phil, funnily enough) who suggested the same thing :) Have ordered some contact cleaner and will have a go at cleaning the selector switches.

Indeed, I have what could be described as the same problem with an old (+20year old) integrated amplifier.

As in your case, the cables don't seem to be the problem, but when changing the source input with the selector, it somehow fixes.
What is a bit more strange is that sometimes, just pressing the amplifier case in some specific parts, fixes it too.  I tried to remove the case some years ago but I couldn't, (weird screws and strongly tied). Else, I would have checked if it was some soldering issue or really just some contact cleaning.

Not noticed if manipulating the case changes the behaviour but otherwise it sounds rather similar. Hopefully I'll be able to get the back off...

Have you a different input on your amp that you can use? It sounds like, as finphil said, that it might be a dirty contact in the input switch.

I have tried a couple. Anecdotally, it does seem to be worse on some. To be honest though, it isn't happening frequently enough for me to get any clear indication. So far it's happened on 3, but I could keep searching for a clean one.

Thanks for the help all. I'll give the switches a clean and lube and see if that clears the problem up!

Re: Loss of sound in one channel

Reply #5
What fixes it is flipping the input selection to another source, then back again. On switching back, the balance has returned and sound is coming out of both channels as expected.

Mechanical switches are among the least reliable components in audio gear.

Quote
Would this suggest that the input switch could benefit from cleaning? For example with some of this:

http://uk.farnell.com/servisol/super-servisol-10/cleaner-switch-contact-200ml/dp/278786

Failing that worthy suggestion, there is a more subtle problem, usually due to a poor termination of an interconnect.   The switch itself may be OK, but when operated it may create a swtiching transient that temporarily clears a failed connection, usually due to corrosion.

That leads to suggestion #2 - disassemble the  entire system by disconnecting the cables, and then reconnect it, inspection each connector for corrosioin or loose wires.

Re: Loss of sound in one channel

Reply #6
I had slightly different problems with a TV settop box via HDMI > Toslink > AMP. Stuttering audio at some moments. When I set the settop box to 1080i instead of 1080p the problem was solved.

Maybe you could try something similar. On my settop box the source material was 1080i so the 1080p setting did not affect video quality. It was even better because the TV's internal deïnterlacer was used instead of the settop box.

Re: Loss of sound in one channel

Reply #7
What fixes it is flipping the input selection to another source, then back again. On switching back, the balance has returned and sound is coming out of both channels as expected.

Mechanical switches are among the least reliable components in audio gear.

Quote
Would this suggest that the input switch could benefit from cleaning? For example with some of this:

http://uk.farnell.com/servisol/super-servisol-10/cleaner-switch-contact-200ml/dp/278786

Failing that worthy suggestion, there is a more subtle problem, usually due to a poor termination of an interconnect.  The switch itself may be OK, but when operated it may create a swtiching transient that temporarily clears a failed connection, usually due to corrosion.

That leads to suggestion #2 - disassemble the  entire system by disconnecting the cables, and then reconnect it, inspection each connector for corrosioin or loose wires.


I terminated my speaker wire with banana plugs and originally thought it might have been a cock-up there, but they're pretty firmly connected and I'm not sure there's much scope for screwing it up (though, you never know). The RCA interconnects between the DAC and the amp are quite old, perhaps it's worth checking them. The speaker wire itself was new and is 18 gauge. Each length is less than 1.5m.[/quote]

Re: Loss of sound in one channel

Reply #8
I had slightly different problems with a TV settop box via HDMI > Toslink > AMP. Stuttering audio at some moments. When I set the settop box to 1080i instead of 1080p the problem was solved.

Maybe you could try something similar. On my settop box the source material was 1080i so the 1080p setting did not affect video quality. It was even better because the TV's internal deïnterlacer was used instead of the settop box.

Unfortunately it happens with the Chromecast Audio as well, which is currently connected via its 3.5mm output to the aux in of the amp and has no video capability. That's an interesting aside though - can you change the video mode on the standard HDMI chromecast?

Re: Loss of sound in one channel

Reply #9
A multimeter that checks continually can be very helpful in finding the culprit.  I suggest one that can also measure capacitors as well.

What to look for:
Bad solder connections
Corroded parts
Soldering flux residue
Leaking or bulging capacitors
Broken or damaged traces
Exposed traces

Re: Loss of sound in one channel

Reply #10
I was reading your post again and switching back and forth between inputs solves the problem temporarily I see. Possibly there is a relay defective and not passing the signal.

What you can do (only if you are experienced in doing this!) is opening the amp and when it occurs tap against the relays one by one and see if there is one that flips over and restores the sound. This could be the relay that switches the A + B outputs.

Reed relays are somewhat more challenging. (made of glass and you can'hear them 'switch'.

Re: Loss of sound in one channel

Reply #11
I was reading your post again and switching back and forth between inputs solves the problem temporarily I see. Possibly there is a relay defective and not passing the signal.

What you can do (only if you are experienced in doing this!) is opening the amp and when it occurs tap against the relays one by one and see if there is one that flips over and restores the sound. This could be the relay that switches the A + B outputs.

Reed relays are somewhat more challenging. (made of glass and you can'hear them 'switch'.

Yes, I think this is not far from the truth. We took the amp apart and discovered that the input "switches" are just connected to an integrated circuit. There is a clicking sound when switching inputs which is indeed coming from a relay on the output. This relay is a fully sealed plastic thing and we couldn't get it apart to clean it. I work with a chap who is much more expert in this stuff than me, and he redid a few of the solder joints on the relay board because some looked a bit suspect, and cleaned where he could.

I've since taken the amp home and reconnected it all. This time I used the "B" speaker outputs rather than "A," thinking that it couldn't hurt to swap them and it might bypass the faulting component or connection. I returned to work today to give the chap in question an update and he said he was also going to suggest flipping the connection to the other speaker outputs so you never know.

So far, the problem hasn't returned. That said, I've only spent about 30 minutes listening to the system, the problem has been intermittent. I switched the inputs a lot and fiddled with the balance and couldn't make the problem occur again, so it's just a question of wait and see I guess. If this hasn't fixed it our plan is to replace the relay itself and see if that solves the issue. As an aside, all the caps looked fine inside the amp - no bulging or anything.

Re: Loss of sound in one channel

Reply #12
Hi, 3 years too late but I had the same problem and fixed it this morning. I thought I would share it so that others could find his solution here as well. I found the solution here.

A good diagnostic is indeed that switching inputs or connecting/disconnecting headphones can sometime fix the problem. If it's the case, the problem is probably the relays for the loud speakers. I found replacement parts on Digikey. I think that Omron relays model "G2RL-2 DC12‎" and "G2RL-2-CF DC12" should both work. I went with the second one.

The solution is indeed to change the relays as shown in this  link. It is kind of easy with the correct tools. Desoldering can be difficult if you don't have the proper tool. I found that unscrew the 4 screws that hold the speaker connectors help a lot to get room to work.

I hope this can be useful to others.

 
SimplePortal 1.0.0 RC1 © 2008-2019