Transformer buzz coming from amp

S

sherjeeldheda

Audiophyte
I have a NAD C-270 and there is a noticable buzz coming from the transformer. I even bought a Tripp-Lite Isolation Transformer to try to solve this problem and it didn't work. In fact, the isolation transformer is also buzzing (louder than the NAD). Any suggestions on how to solve this problem would be much appreciated.
 
M

MBauer

Audioholic
Basic Troubleshooting

Have you tried any basic trouble shooting? (you don't mention it, so I hope I am not going over old ground). I take it you mean the transformer inside the amplifier is humming, not that it is introducing a hum into your playback? If that is the case, have you used a different electrical outlet? If that doesn't change it (and it likely will not) it most likely has a bad filter cap. It could be a loose enclosure but since I don't know the nature of the hum it is hard to diagnose from afar. How loud is it? Can you hear it from your normal listening position? Does it introduce any audible into your playback? Does it add any video noise to your display?

If it is really a loud noise I would take it back as it is probably not user serviceable
 
S

sherjeeldheda

Audiophyte
MBauer said:
Have you tried any basic trouble shooting? (you don't mention it, so I hope I am not going over old ground). I take it you mean the transformer inside the amplifier is humming, not that it is introducing a hum into your playback? If that is the case, have you used a different electrical outlet? If that doesn't change it (and it likely will not) it most likely has a bad filter cap. It could be a loose enclosure but since I don't know the nature of the hum it is hard to diagnose from afar. How loud is it? Can you hear it from your normal listening position? Does it introduce any audible into your playback? Does it add any video noise to your display?

If it is really a loud noise I would take it back as it is probably not user serviceable
I tried plugging in just the amp into another outlet in another room, and the buzz did not go away. It is definitely a mechanical hum, and it does not introduce an audible hum from the speakers. I can hear it from my listening position when the room is silent.

If it is a bad filter cap or a loose enclosure how do a go about locating the source, and how do I fix it. (I bought the amp over the interent.)
 
P

PENG

Audioholic Slumlord
All transformers hum but some louder than others. There are products that claims to be able to remove any d.c. offset components in the supply circuit, (wall outlets) that would in turn reduce the humming noise. I have owned a Sony DA4ES, Denon 3803, a Byston amp, and an Adcom amp. The Denon and the Adcom (has toroidal transformers) are barely audible unless I stick my ears to the enclosure, the Bryston (has a toroidal transformer as well) and the Sony are quite a bit louder, the Sony XBR 36" TV is even louder. Anything loose inside could resonate with the transformer vibration, thereby increase the humming noise.
 
Last edited:
M

MBauer

Audioholic
Careful

sherjeeldheda said:
I tried plugging in just the amp into another outlet in another room, and the buzz did not go away. It is definitely a mechanical hum, and it does not introduce an audible hum from the speakers. I can hear it from my listening position when the room is silent.

If it is a bad filter cap or a loose enclosure how do a go about locating the source, and how do I fix it. (I bought the amp over the interent.)

I am hesitant to advise you to open up your amplifier. The power supply uses capacitors which can retain high voltage for sometime and give one a very serious shock.

My first piece of advise is get the schematic for the amp. That way you can look at the power supply and determine where the filter caps are. If you are not a skilled audio amatuer or better this is better left to a shop which has the proper equipment. There is a very slight chance this is mechanical - something loose which is vibrating
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
sherjeeldheda said:
I have a NAD C-270 and there is a noticable buzz coming from the transformer. I even bought a Tripp-Lite Isolation Transformer to try to solve this problem and it didn't work. In fact, the isolation transformer is also buzzing (louder than the NAD). Any suggestions on how to solve this problem would be much appreciated.

I am willing to bet you have a mechanical hum created by the 60Hz current. It needs a mechanical fix.. Either the screws holding it to the chassis is loose or the plates in the transformer have enough play in it to vibrate.

You may want to pull the cover and see if by applying a finger, changes the sound? If it alters it, you are on the right track.
 
W

wanjeyin

Enthusiast
I've got the same problem on my JBL e150p sub. Although not loud, it is there and annoying at times. I confirmed that the buzz is coming from my transformer as I opened my sub box and heard a distinctive buzzzing from the transformer laminates. Note, the transformer is not one of those toroidal variety.

All the screws are tight and outer laminates appear to be secure. The buzzing seems to be coming from the innards of the transformer, which I dare not touch. :eek:)

Is there some sort of cheap fix or inexpensive filter-like device that any of you can recommend? I'm fairly confident that some sort of a DC filter is what I need. Given that I"m an amateur, however, i'm not comfortable with schematics and DIY type of stuff.

Please help kill the buzzz!!!!!

Regards,
AJW
 
P

PENG

Audioholic Slumlord
I know of at least one product that claimed it could filter out the d.c. offset, but it may not be your problem. Transformers do hum, just that some are louder for various reasons. If it is not noticeable from several feet away, you may want to leave it alone.
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
wanjeyin said:
I've got the same problem on my JBL e150p sub. Although not loud, it is there and annoying at times. I confirmed that the buzz is coming from my transformer as I opened my sub box and heard a distinctive buzzzing from the transformer laminates. Note, the transformer is not one of those toroidal variety.

All the screws are tight and outer laminates appear to be secure. The buzzing seems to be coming from the innards of the transformer, which I dare not touch. :eek:)

Is there some sort of cheap fix or inexpensive filter-like device that any of you can recommend? I'm fairly confident that some sort of a DC filter is what I need. Given that I"m an amateur, however, i'm not comfortable with schematics and DIY type of stuff.

Please help kill the buzzz!!!!!

Regards,
AJW
If not the plates, which it still may be even thought the plates are screwed well, check the mechanical connection to the chassis it sits on?
Last resort, call the makers.
 
W

W_Harding

Junior Audioholic
Buzz

Sometimes placing rubber grommets between the transformer and the chassis will eliminate or reduce the buzz. I have had some success on a couple of pieces of electronic equipment using this technique.
 
W

wanjeyin

Enthusiast
The trouble is that the noise is not coming from the outer laminates. Rather, the hum is originating from the mass of wires from WITHIN the laminates.

If we can solve this one, we might be able to solve a large portion of mysterious humms out there! :eek:)

I'll try taking a picture and posting it.

Stay tuned.

AJW
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
wanjeyin said:
The trouble is that the noise is not coming from the outer laminates. Rather, the hum is originating from the mass of wires from WITHIN the laminates.

If we can solve this one, we might be able to solve a large portion of mysterious humms out there! :eek:)

I'll try taking a picture and posting it.

Stay tuned.

AJW

Since you are in there playing:D try a rubber grommet between the wire bundle and the plates, forcing a tighter mechanical connection and perhaps isolating the wires? May need more than one at strategic locations?
 
W

wanjeyin

Enthusiast
Would a shot of silicone work? If so, would a little work, or would I need gobs?

Thanks again!

Regards,

AJW
 
W

wanjeyin

Enthusiast
.......or would I cause a massive short-circuit?

;)

AJW
 
P

PENG

Audioholic Slumlord
wanjeyin said:
.......or would I cause a massive short-circuit?

;)

AJW
Not likely, most silicone stuff have reasonable insulating capability, but make sure you don't reduce its ability to dissipate heat. Again, as long as you don't hear it from several feet away, you may consider leaving it alone. Go to any high end stores, stick your ears to the chassis of most amplifiers you will hear the transformer hum. Its not that easy to silent the vibration due to the 60 Hz and its harmonics.
 
M

mitch57

Audioholic
I had the exact same problem with two different Amps (Rotel RMB-1095 and Parasound Halo A51). I tried just about everything under the sun to stop the amp from buzzing. Just for the record, this was not a ground loop issue. I had no buzzing coming from my speakers.

This is what completely silenced the problem I was having.

http://www.psaudio.com/products/upchb.asp

I was quite skeptical at first but the company told me they would take it back and pay the return shipping if it didn't solve my problem. It did solve my problem and needless to say, I still have the UPC-200HB and haven't looked back since.

The problem in my case was related to noise on the power line. I live in the boonies up on a mountain in the woods. Most of the few neighbors that I have own shops with large power hungry/noisy equipment like lathes, saws, and welding machines. I think all this equipment creates noise on the line and caused my amp to buzz.

But I'm happy to say.... Not any more! :)
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
wanjeyin said:
Would a shot of silicone work? If so, would a little work, or would I need gobs?

Thanks again!

Regards,

AJW

If you have some in the shop, try a little here and there, let it cure overnight and have at it.
 
P

PENG

Audioholic Slumlord
mitch57 said:
I had the exact same problem with two different Amps (Rotel RMB-1095 and Parasound Halo A51). I tried just about everything under the sun to stop the amp from buzzing. Just for the record, this was not a ground loop issue. I had no buzzing coming from my speakers.

This is what completely silenced the problem I was having.

http://www.psaudio.com/products/upchb.asp

I was quite skeptical at first but the company told me they would take it back and pay the return shipping if it didn't solve my problem. It did solve my problem and needless to say, I still have the UPC-200HB and haven't looked back since.

The problem in my case was related to noise on the power line. I live in the boonies up on a mountain in the woods. Most of the few neighbors that I have own shops with large power hungry/noisy equipment like lathes, saws, and welding machines. I think all this equipment creates noise on the line and caused my amp to buzz.

But I'm happy to say.... Not any more! :)
As I mentioned earlier, filtering networks would work if (and only if) his problem is due to dirty power, e.g., presence of d.c. components.
 
M

mitch57

Audioholic
PENG said:
As I mentioned earlier, filtering networks would work if (and only if) his problem is due to dirty power, e.g., presence of d.c. components.
Your are correct. However, I seriously doubt that the problem is concentrated in the transformer/windings of his amp. If this were the case, it would be easily diagnosed by taking the amp to another location, such as his dealer, and doing a test with the amp plugged into the dealers wall outlets without any filtering or surge protection.

I found that my problem did not exhist when I took my amp to the dealer. He plugged it in to his wall outlet and the buzz was non exhistant. Both amps were dead silent at the dealers showroom. Please keep in mind that the dealer did not have any filtering going on when I plugged in my amp. We just plugged it into a standard wall outlet.

I personally don't see the need/advantage of using silicone or other means of silencing the amp unitl you positively identify where the buzzing is coming from.

In my particular circumstance, I positively identified that the problem was not resident in the amp, but in the power coming into my house. I am only suggesting that "wanjeyin" first identify if it truly is coming from the amp or from his power source. Plugging the amp in to another power source in a different town or at least a different suburb should provide the answer.
 
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