amp dies in middle of playing


I have an old adcom amp that occasionally dies whenever i play bass heavy passages at high volume. This is a new problem as the amp used to drive to far higher levels with no problems. The way it happens is ill be playing a rock song at loud but not rediculous volume, like 11 on my preamp and the music will cut off and then come back on after the amp protection circut turns back off. I think its a power supply problem but any suggestions would be greatly appreciated.
sailor720
Did you buy your pre-amp from the dude in Spinal Tap? I know all his gear went to eleven. Now that's a MOD :^)
Have you changed speakers or speaker cables ? If using a combination that is more reactive, the amps' protection circuitry could kick in sooner. Otherwise, it is not uncommon for circuitry to degrade with age. This is especially true if exposed to higher than normal heat levels and the inside of a power amp qualifies as such. You can probably send it back to Adcom for inspection and repair, as their prices for doing so are typically quite reasonable. Sean
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PS... Glen, i think he meant "11 o'clock" : )
I believe that Adcoms have internal thermal protection, it could be that it is just getting too hot. Place it all by itself, NOT in a cabinet or with other stuff stacked on top, and NOT sitting directly on carpet.
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Viridian brings up a very good point. I have run across situations where fuses were not blown, but the device was not getting enough juice through the fuse to function properly. Kind of a "that shouldn't work, but it does" type of situation.

Sometimes just pulling the fuses and re-installing them can break up a resistive connection and restore proper operation. It is worth a try and cheap to boot. Just be careful and make sure that the amp is unplugged and the power supply discharged before sticking your hands inside of any electronic device.

You can typically discharge a power supply by unplugging the product from the wall and then turning it on. The circuitry will then try to energize, drawing power from the filter capacitors and discharge them. This could take time though, so let it sit for a bit while you do something else. The bigger the filter capacitors or "cans" inside the device, the longer it will take to discharge them.

This is especially true of power amps with no signal being applied. As such, you can simply leave the amp in the system, unplug the amp from the wall, turn the amp on at low level and continue to play music ( at reduced volume ) until you hear the volume dropping out quite noticeably. There may still be some residual voltage present in the amp at that point, but chances are, it is not hazardous. You can then remove all cables and proceed to inspect the internals as needed.

Hope this helps.... Sean
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Viridian makes a good point. I had a problem with one of my M120 monoblocks, where it's sound was very bad on mid-deep bass. Fuses seemed OK, but closer inspection showed 2 were semi-blown. Replacing the 2 fuses solved the problem.

KP