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71.105.100.74
Hi,
I'm hearing a dropout of sound from one speaker in a 2-channel system, then it may come back on suddenly. No audible hum or distortion or fade in volume noted when this happens. My troubleshooting has excluded my preamp, interconnects from pre-amp to power amp, speaker cables, or speakers. Seems to be a problem with the left channel of the power amp, a BEL 1001 solid state amp that's 20+ years old. Great sound, then off, then unpredictably back on. Interconnects and speaker cable appear solidly connected to RCA jacks and cable binding posts.
Any ideas what this might be due to?
Thank you and happy listening,
Harvey
Follow Ups:
The Model 1001 takes full advantage of these performance enhancing measures and maintains reliable operation with an elaborate fault sensing system. It allows unrestricted operation of the amplifier while protecting against load faults and improper inputs including rf, ultrasonic and subsonic.
Above, from the Bel site, gets my vote. Amp thinks, for whatever reason, there is a fault.
I'd start swapping stuff L/R until I narrowed it down. As soon as you can get the OTHER channel to fault, you've got it.
#2 vote? Who mentioned the speaker relay?
Too much is never enough
Hi,
Thank you. I'm pretty sure this is affecting only the left channel of the power amplifier. When I swapped the speaker cables, i.e. left binding post on amplifier output to the right speaker, the dropout was now on the right speaker instead of the left speaker. I took the top cover off the amp, and after one look decided to leave this to a professional to troubleshoot/repair--there is a circuit board at the back of the amp with very little clearance.
A poorly solder joint can rear it's head at any time, even at 20 years. I would open the amp and carefully heat the connections on the output posts to remelt the solder.
On the violin: "Heaven reward the man who first hit on the idea of sawing the innards of a cat with the tail of horse."
Hi,
Although sounds simple, my previous (long ago) attempt to solder a resistor to an RCA connector (for loading phono input) didn't work out; I will pass this suggestion along to a friend who is skilled with a soldering iron. Like the quote about the violin...
Thank you,
Harvey
My ss amp would not produce sound from the left channel upon power-up. Power it down and back up, and the sound would return. I pulled the cover and re-seated every connector I could get my fingers on. That was 4 or 5 years ago and the problem has yet to return. I would unplug it, remove the cover and re-seat connections.
Hi,
This sounds exactly like the problem I'm hearing. I may take a look -- your amp has internal connections that simply pull apart and can push back together?
Thank you.
Molex connectors are white plastic, usually one end mounted to a pcb, the other on the end of a wiring harness. Just be gentle. Any plastic connectors inside a 20-yr old amp could be brittle.
I have taken working amplifiers apart and cleaned all the interconnect and board-edge connectors with Caig De-Oxit, they always sound better afterword.
Does it have a speaker relay?
First thing I'd check.
Hi,
I don't know, but my friend who repairs audio equipment will obtain schematics next week. Thank you very much for the suggestion.
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