sub amplifier problem

[testarossa2k]

I have the RCM Detonation DT 80 amplifier, and when it's on I hear a light hum, wich is not audible when music plays. I can hear it from 2/3 meters, I mean I don't put the ears on the back of the amplifier to hear it. It doesn't come from the speaker, but from the amplifier itself. Is it normal and safe? is there any quality loss in terms of sound?

thank you very much.

[richie00boy]

Sounds like it has a toroidal transformer in the power supply which is sensitive to imbalanced AC line currents. You could build a DC blocker circuit, or wait for another day when the mains is in better shape.

[testarossa2k]

or wait for another day when the mains is in better shape

what do you mean? I have to change something in the mains? sorry but I'm not very expert in "current" things

The amp is new and so if it's faulty I can change....

[mrshow4u]

I've got a similar issue. I've got 5 Meyer HD-1's, all with torroids. They all used to mechanically buzz. With an isolation transormer, I looked at the quality of our locale's AC. It just sucked!!! Very viewable on a normal scope. I didn't have to take a THD reading. Lot's of ugly harmonics and asymmetrical. (Thanks PG&E). I got a 1000VA isolation transformer, because it didn't care so much about the distorted AC, and voila the Meyer's quieted down. The downside is, the transformer is a heat generator. Outside of that, I haven't noticed any ill affects.

[richie00boy]

Originally posted by testarossa2k


what do you mean? I have to change something in the mains? sorry but I'm not very expert in "current" things

The amp is new and so if it's faulty I can change....

I mean wait for another time when there is less rubbish being put into the mains supply by other people or even appliances in your own house.