Some amps have noise at idle and there is no way to fix it. Zero feedback designs are most prone to this problem, of course, and so will always be noisier than those with some feedback. If it was coming from your woofers it could be sub-optimal grounding but from your mids, it is the amp IMO. As long as you don't hear it at all from your chair, I would overlook it.
Arthur |
I have recently noticed the exact same problem from my amp in my bedroom system. The amp is an 80 watt class A and with nothing else connected other than speakers, there is a hum from the mid/bass and a hiss from the tweeter - doesn't change with the volume control. The hum is audible from about 1 metre from the speaker. Unlike your situation, however, I can hear a very slight hum from the amp itself as soon as I swith it on from standby.
Hooked the amp up to less efficient speakers (85db compared to 90db) and whilst the hum remained, it was much lower.
Not audible from the listening seat, but just knowing the hum is there is frustrating and reduces my enjoyment of the music! I think if this is normal from this amp's design, that is very poor.
I'm returning the amp to the retailer to check while still under warranty. |
It's probably considered "normal" from a ss-multi-channel amp. Many multi-channel receivers and amps do it. It seems to be the nature of the beast. The more efficient your speakers are (and the closer you sit) the more you will notice it. |
I have the same hum problem with my amps... audible from the amps and through the speakers. Cheater plugs don't help. Has anyone tried PS Audio UPC 200 Humbuster?? Does this thing really work? |
Hens, Sometimes, perhaps one out of every ten 'power ons' the amp will emit a little vibration/rattle but then settles down to dead or near dead silent operation. I don't have any abnormal quirks like sound cutting out, volume change, run hot, harsh distortion, it operates fine imo. However, I don't have it on a test bench w/ test equip and would not know what to do if I was in such a sutuation. Question, amp and recv'r both have pwr cords that are 2 prong male/2 hole female. The cords are removable type but only 2 terminals vs 3 ? Perhaps a gnd issue? I assume the manufacturer designed it knowingly. Amp list 2k and recvr list 3k new. Although I did not pay that much. Should I forget about it and just crank it/enjoy!? |
I've got it too through my ss mono blochs. Haven't tried to do much in terms of fleshing it out. I just considered it the nature of electronics. Mine is only audible with my ear right at the tweeter but does increase/decrease with volume control.
What do ya know. |
Tiffany...I have read according to ps audio's website that the unit will indeed eliminate all if not most of internal transformer hum. In fact, I visited the site to do some research and according to them, if I remember correctly, an amp that hums w/o any thing connected is perhaps in need of repair. But owners here say it's the nature of the beast!!!!???? I should be grateful it powers up and works. But that hiss, buzz, slight hum is still bugging me. I don't see how an electronic device that received superb reviews and price lists in the thousands can be broke if it makes a little bit of noise. But then again...? |
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! |
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. |
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? |
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"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. |
I think most homes do have 15 amps and it's a good idea for you to upgrade yours...but I don't think that's why you're having the hum issue. I have a mixer/amp that hums loud and I managed to minimize that dramatically by just using the "cheater" plug. My Cary Rocket 88R is dead quiet despite cables overlapping and touching everywhere! My Cary V12i's mono blocs are the ones that hum and with my set up, it's impossible to keep the cables separated. I would have to sell all my cables and buy new lengths to accomplish that.
I will try to get my hands on a humbuster and let you know if it really works. In the meantime, we may have to just take many others' advice that it's "the nature of the beast" and overlook it as long as you don't hear the hum from your chair. With having said that, the room is soooo much quieter once I shut off the amps :( :( :( However, the music is still sublime :)
And if you haven't done so, try the cheater plug on your amp. |
How do I short input to one ch? Would you explain process please...thanks. |
Mnnc...One way would be to plug in an interconnect, and then, at the other end, short the center pin to the body of the rca connector. "Short" means touch something metal (like a screwdriver) to both parts.
By the way I notice that you are using a receiver as a preamp. I assume that the receiver has connections for "pre out" and "amp in" that are normally jumpered. This probably means your signal into the new amp is not low impedance as from a dedicated preamp. |
Eldartford...recv'r has dedicated pre-outs for external amp. No amp ins but has analog external/multi ch ins for dvd-a/sacd. No jumpers. As far as shorting an ic, bridge the rca center post/pin to the side using a screwdriver or buck knife? And what do I look for/listen for then. Sorry for the ignorance. I'm learning. |
Eldartford...connect rca from recv'r or amp? |
Connect it to the amp which makes noise. See if the noise goes away when you short its input. Does your reciever have a spec for the output impedance of its pre-outs? 50 ohms or less would be nice. |
Eldartford...specs read pre out (front, center, surr, surr bk, sw) 1k and then a little horseshoe looking symbol/ohm?and then 1.0V Chinese to me. Thanks for the schoolin' |
those specs were listed after the output level heading...it listed the tape monitor rec and then pre out. |
Mnnc...Yes, the little horseshoe means "ohms". 1K ohms means 1,000 ohms. This is quite high. Many tube preamps run about 600 ohms, which is OK for input to most tube amplifiers, but not the greatest for SS amps. Solid state preamps usually run 50 ohms or less. I am not surprised that your receiver is 1K...it was not really designed to be a preamp.
Did you try the shorting experiment? It just might work. Of course it won't solve your problem, but if you know the reason you may be able to live with it. |
