signal loss in 1 channel in stereo with 3 amps

V

vin13

New Member
Hi, I'm having an issue with 3 amps / receivers - Pioneer SA7800, Marantz 2275 / 2252. The same with all 3. I'm loosing signal in one channel in stereo. I get signal in both channels when I switch to mono. I've used different speakers and cables. This doesn't happen all the time, perhaps half the time. Perhaps I'm missing something obvious. Has anyone any ideas?
cheers.
 
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variables

:scratch2:Hello vin13; your description of the symptoms contains too many variables. Can you boil it down a bit.

A few things to consider:

Do these failures involve the same signal source (ie vinyl, CD, tuner, etc) or do you hear both channels for one source but not for others?

Experiment with different signal sources to try and determine some pattern.

Do both channels work through headphones?

Approach this methodically, change only 1 thing at a time and note any changes caused by this single change, if any.

Since the problem isn't changed by using a different amp, then the problem is not in the Amp(s).........froogAL the joy of the "fix"
 
If you trace back through the circuit you should be able to determine the point at which the signals are combine for mono, often in the tone control area. That should help to isolate the problem.
 
Do these failures involve the same signal source (ie vinyl, CD, tuner, etc) or do you hear both channels for one source but not for others?

Yes, I have 2 set-ups in 2 different rooms, one with the SA7800 and one with the 2275. I've switched everything around and tried the 2252 too. So I've used 2 cd players, 2 turntables and an ipod on each. I've used main and remote spreakers outputs.

Experiment with different signal sources to try and determine some pattern.

Do both channels work through headphones?

I haven't tried headphones, I knew I was missing something obvious. I will do so when they start acting up again. They're working again now, but the problem will likely surface again.


[I]Approach this methodically, change only 1 thing at a time and note any changes caused by this single change, if any.

Since the problem isn't changed by using a different amp, then the problem is not in the Amp(s).........froogAL the joy of the "fix"[/QUOTE][/I]

it does seem to be a coincidence, but as it's old gear I thought it wasn't impossible.

Thanks for you help
 
Until that last post I had no clue that the problem was intermittent. That changes the analysis completely.

As froogAL suggests, a systematic approach to eliminating possibilities will be helpful.
 
intermittent channel

It sounds to me like dirty switch contacts. Caig chemicals offers excellent contact enhancing fluids for such failures. Money well spent. I like D-100L in the nifty 25ml needle squeeze bottle. Caig changed the name a few years back. The 25ml(cc) bottle works out to around $1.00/ml(cc) delivered.......a lifetime's supply unless you use it for cocktails.

If both systems in the two separate rooms fail simultaneously call a priest.......froogAL
 
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Out of the blue today, I wasn't hearing any sound out of my left speaker. I switched between phone, FM and another source -- same issue. Bypassed the amp and ran straight from my 2235b to the speakers -- same issue, so I knew it wasn't the amp.

Pushed in the Mono button and sound came out of both speakers evenly/powerfully. Depressed the Mono button and when I turned up the volume to 12 o'clock, I could hear sound faintly from the left speaker.

Searched on AK and saw the post below. I plugged my headphone jack in and all of a sudden I started getting sound out of the left speaker in stereo, both with the headphones plugged in and not.

First off, thanks to FroogAL for the idea -- it appears to have "fixed" the problem! :thumbsup:

That said, any idea why that happened and what plugging the headphone jack in might have triggered to produce sound out of the left channel in stereo? Is there is anything I should do to help prevent that from happening again (Deoxit)?

Thanks in advance, all!


froogAL said:
variables

:scratch2:Hello vin13; your description of the symptoms contains too many variables. Can you boil it down a bit.

A few things to consider:

Do these failures involve the same signal source (ie vinyl, CD, tuner, etc) or do you hear both channels for one source but not for others?

Experiment with different signal sources to try and determine some pattern.

Do both channels work through headphones?

Approach this methodically, change only 1 thing at a time and note any changes caused by this single change, if any.

Since the problem isn't changed by using a different amp, then the problem is not in the Amp(s).........froogAL the joy of the "fix"
Click to expand...
 
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