Yes the mains will be run full range. I took the amp to a friend's house and plugged it into his system and there was no 60 cycle hum however his house has no third wire... two prong plugs only. But whatever noise such as to brush Etc came out of the speakers when no signal was present that noise completely disappears after 4 seconds. now we are thinking maybe the crown is muting the signal. someone suggested it has a muting circuit that is supposed to come into play after a few minutes of silence. perhaps it's a little overactive. Having a tech look at it right now to be sure. when I get it back I'll try it with a cheater plug again and see if that helps with the hum. I have the DSP mini now and we'll hook up with the crossover. crossover alone may eliminate all the hum.
Hum mystery - Crown K2 amp driving passive subs
Need advice. Just bought a Crown K2 500-watt amp to drive two passive subs. I will be running them through a dspmini crossover to augment my main speakers. Main system is Berning custom 6sn7 all-tube with tube rectified switching power supply, feeding Quicksilver v4 monos, into Verity Parsifals. Before I got the Crown amp I tried a 60-watt Rotel to drive the subs. No issues or hum with the Rotel.
Before I get the dspmini I was testing the amp. I am runnng it off the second pair of outputs from the preamp. With the Crown, the weirdest thing happens. When I turn on the Crown it hums through both speakers for about four seconds, then goes totally quiet. But the moment the slightest signal is put through -- whether music or just a little DC from rotating either of the Crown's gain knobs -- the hum returns. If I dont continue to apply signal the hum goes away in four seconds. If signal continues the hum continues until the signal stops. Again, this does not happen with the Rotel, wired exactly the same as the Crown. The hum also has some higher frequency noise, but mostly it sounds like 60 cycle hum, moderately loud. Too loud to live with.
Sounds like grounding? Would pro gear like the Crown be more susceptible? I dont imagine the huge power difference between the amps should matter. Any ideas? The Crown does not hum at all with inputs disconnected.
Thanks for any help.
Before I get the dspmini I was testing the amp. I am runnng it off the second pair of outputs from the preamp. With the Crown, the weirdest thing happens. When I turn on the Crown it hums through both speakers for about four seconds, then goes totally quiet. But the moment the slightest signal is put through -- whether music or just a little DC from rotating either of the Crown's gain knobs -- the hum returns. If I dont continue to apply signal the hum goes away in four seconds. If signal continues the hum continues until the signal stops. Again, this does not happen with the Rotel, wired exactly the same as the Crown. The hum also has some higher frequency noise, but mostly it sounds like 60 cycle hum, moderately loud. Too loud to live with.
Sounds like grounding? Would pro gear like the Crown be more susceptible? I dont imagine the huge power difference between the amps should matter. Any ideas? The Crown does not hum at all with inputs disconnected.
Thanks for any help.
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- 4 posts total
- 4 posts total