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Buzz/hum from Spectron Musician II amplifier.

Cross posted in amp forum: Just purchased the unit from another 'Goner. It makes phenomenal music, but has an electrical buzz/hum upon power-up which comes up slowly and then reaches a steady state after about 3-5 seconds.

No noise through the speakers, thank goodness, but from inside the case itself. It is just loud enough to be barely audible from about 10" away. Incidentally, the amp in my subwoofer is doing the same thing and both are on the same circuit, so I suspect noise coming through the circuit. The seller confirms he had no such problem, which tends to reinforce this conclusion.

I tried to reverse the ground - using the 79 cent 3 prong to 2 prong adaptor. No luck there. Hum was also present when plugging into through a Panamax power condition on the same electrical circuit. I am out of ideas. Anyone?
jswarncke

Showing 4 responses by jswarncke

jswarncke OP
66 posts
 
Thanks - this seems to be the consensus in the cross post as well. I am going to take the amp to another house and see what happens, and see if I can diagnose the voltage, as well.
jswarncke OP
66 posts
 
Problem was completely solved with a Channel Islands Audio XDC-2 AC filter. definitely transformer hum from DC noise riding on the eAC line.
jswarncke OP
66 posts
 
When I spoke to the guys at CI, they confirmed that there is a maximum draw per plug on XDC-2. I don't know whether you can do what you propose, but the CI guys can tell you very quickly I am sure. I think in the traditional configuration the max draw per plug is 7 amps - but they can also build the XDC in parallel (??? forgive my lack of tech knowledge) which means as long as the total draw on both plugs does not exceed 14 amps then all is well. That's the way they built mine, at no extra charge, and I have a 500 watt/channel Musician amp and a 450 watt subwoofer amp drawing on the unit without trouble.

What is a Musician II Hybrid?
jswarncke OP
66 posts
 
Thanks for the reply. I looked at the Spectron website, but would be interested to hear your long term impressions on the upgrade. Seems the price is right for 90%+ of MIII performance (if that is the case).

I noticed that you are using DH speakers cables. I am doing the same, except in the Remote Sense config. I am in the process of trying to acquire some Cardas Golden Cross b-wires as an experiment. My system balance is presently good to very good, but not great. It has a tendency to get a little hot and edgy in the high end which causes me to play at a lower volume than I would like sometimes. The good news is that even at low volume the system is very detailed and dynamic - probably the flip side of the forwardness.

The Golden Cross are known to be very warm cables which tend to tame glaring, edginess etc, but still with plenty of detail and resolution. I noticed in one of the Musician II reviews the reviewer preferred his usual cables to the Remote Sense. I hope to give them a try withint the next few weeks. . .
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