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added amp...now hiss from spkr's

Addd an amp to the mix. SS multi-ch. Had no problems prior in relatively simple rig or atleast I did not notice. After making connections to recv'r(now used as pre/pro) I noticed a slight hiss/static like sound comimg from mids on my spkr's. So the process of elimination/isolation began. Long story short, I narrowed it down to the hiss/buzz coming from spkr's with only the amp connected. Nothing else...no interconnects no nothing. That cancels out cable problems, bad dvd player, etc, etc. Just power cable plugged in and wires going from amp to spkrs. When powered on it makes the noise. Amp runs quiet as far as I can tell when putting ear next to it. What's the deal? Tried diff outlets, diff spkr...makes no difference. When taking amp out of the mix and connecting spkr's to recvr, there is no noise at idle. Amp plays fine/sounds fine but the noise, although slight, is bugging me to pieces. Amp was shipped to me and had shifted cady/catty corner while in it's factory packaging which is pretty substantial. Perhaps it took a hit/drop...weighs about 80 lbs! Could something have gotten jared loose...a transformer which it has two of and quite large. Or is it the nature of the beast to output some noise when at idle? Thank you.
mnnc
tiffany
8 posts
 
Mnnc, it's tempting to buy the PS Audio Humbuster and give it a try (I missed one on sale here for $150!) ....or simply send the amps back to the manufacturer for new transformers. But if it's truly "the nature of the beast" as many believe, then I would be wasting my money either way. Other people in the room don't notice the hum, but I KNOW it's there and like you, that bugs the heck out of me...because I've spent too much money to have something that hums & hiss as if it's defective.

Another advice I heard on minimizing the hum is to make sure the power cords don't touch any of the interconnects...or buy better shielded cables.

Hopeless!
mnnc OP
175 posts
 
That was/is a super price. It won't be the last though. What amps do you have? Have you isolated your pwr cords? Not an exagerated seperation but rather not touching. You may want to post a thread specific to your brand and make notes of feedback received by other owners of the same unit/s. I've tried to contact some people that have what I have but have not recv'd a response as of yet. Contacted the manufacturer via email a couple days ago and no word...waiting. I am going to call them direct. Let your voice be heard! Ask quesions until something is resolved is the way I see it. In the meantime go listen to some tunes...I am. Keep me/us posted.
mnnc OP
175 posts
 
Just realized something but don't know if it has anything to do w/ my stereo issues or not. My recv'r has 7A on the back and the amp has 10A on it printed. That is a lot of pwr consumption is it not?...well, my fuse box/circuit breaker in the garage has a bunch of switches/breakers that have 10a....so me electrical jargon. Do I have a 10 amp breaker box as opposed to many people that refer to 15 amp or 20 amp braker box/line? If that is the case well, I have a prblem there as I would be drawing more than it is giving on that circuit wouldn't I. I am not an electrician by no means. I can do some basics like hang a ceiling fan/change a socket, etc. Any input...anybody?
freemand
225 posts
 
Mnnc,

What amp is it?
eldartford
4,262 posts
 
"Hiss" and "static" have nothing to do with AC power cords and the like, which can cause hum. You are probably hearing a characteristic of the amp electronics. Since all channels of this multichannel amp have the problem it probably means that there is no fault. It is only recently that we got amps which are dead quiet. In the good old days all amps made a little noise...that's how you knew they were turned on. The only thing I can think of which you might try is to short the input to one channel and see if it gets less noisy. If so it suggests that a preamp with low output impedance might help.
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