"Buzz" Coming Through Speakers


I have a Audio Research SP16 tube preamp. I recently noticed that without any music being played (or during quiet music passages)there is an irritating "buzz" coming from the speakers. Since the tubes had considerable play time over several years, I replaced the tubes. However, the "buzz" continued. In the past, changing the tubes resolved the problem. But not this time.

I would appreciate any thoughts you might have. Thank you so much.

Kit
kitjv
Had that same problem with my McIntosh MC 205. Use a "cheater" plug. It is adapter plug that makes a 3 prong plug into a 2 prong plug. It cost less than $1 and u can find them at your local hardware store or Walmart. Make sure u bend back the metal tab so it does not touch the metal screw on your socket plate or use the top socket.

Hopes that solves your buzzin' problem. Good luck
I assume that you are referring to the plug on the power cord of the preamp. If so, you would be effectively eliminating the grounded prong of the plug. Correct?

I am curious how this might resolve the "buzz" problem since the problem only started recently. Thank you.
How are you sure the problem is with the preamp and not
something else causing the buzz? If it is not on a dedicated
circuit you can start unplugging anything that is plugged in
to that circuit. A dimmer switch is a known source for
producing a buzz.
You may try lifting all your cables off the floor, making sure no cables are touching one another, and crossing cables at a 90 degree angle -- not parallel.
The audio system is plugged into a general lighting circuit. With all lights in that circuit off, the buzz persists. So a dimmer switch is assumingly ruled out.

I unplugged (one by one) all of the audio/video components plugged into that circuit. The buzzed ceased only when the preamp & the power amp were unplugged.
Plug in a component directly into the power amp leaving the preamp out of the loop and see if the buzz goes away. I presume you have no power conditioners plugged in.
In the past, changing the tubes resolved the problem. But not this time.
It appears that the line stage version of the SP16 uses three 12AX7's, and the version which includes a phono stage uses three more. Not sure which version you have, but in any event it may be worthwhile to try swapping the tubes around among the various locations in the preamp.

Regards,
-- Al
The first thing to do is verify that the preamp is indeed the culprit. To this end:

run the amp with no input- no interconnect cables attached. Is the buzz still there? If yes- its the amp, if no:

Reconnect the preamp. Do not have any other component attached. This is important- if a ground loop is causing this it can be coming from another component. Is the buzz present? If no, swap the interconnect cables left for right at the preamp end and see if the problem moves. If it does, the preamp is indicated. If it does not, its a cable.

If yes, in both channels: Try floating the ground pin of the AC power cord as suggested on this thread. This is for testing only. If this fixes it, you need to talk to the manufacturer about fixing the preamp's ground problem. If it does not, you need to talk to them about fixing the preamp- any number of internal faults can cause this.

Good Luck and please report your findings.
I'm in 100% agreement with Atmasphere. You will see many suggestions to use a cheater plug permanently to eliminate (mask) a ground loop problem. As Atmasphere suggested, use it only to identify the problem with the amp or pre-amp. After you have identified the problem, fix it. not by using the cheater plug permanently, but by actually fixing the problem. It could be a wiring problem in your house or a problem with a component. Sometimes it can be the interconnect cables. lifting the ground on a permanent basis is not a good idea. It is actually akin to removing your brake pads in your car. You don't need them until you have to apply the brakes. using a cheater plug removes the path to ground. If there is a fault, electricity will try to find another path to ground. It may be you, your pet, your family member, etc. I would bet that it is a problem in your amp or pre-amp that has come about recently. A faulty power supply filter cap or something else in the amp or pre-amp. If it was working fine before, maybe a dimmer switch is going bad. Some dimmer switches click off completely and some only turn down but not completely off. I know you will find the problem and resolve it.

enjoy
Kit, I honestly do not know why u would get a buzz now that u did not have b/4. That is kinda strange. Did u plug something new on that same circuit like a computer, printer, modem,...........

I agree with Atmasphere about determining if it's the pre-amp or amp. Willing to bet it is going to be the amp.

In my situation, I purchased a brand new McIntosh MC205. And had a buzz in the #5 channel. I did take it back to where I bought it from but they did not hear the buzz. Said that I had a ground loop problem, etc etc etc....... I did all that unplugging and moved cables and still have that buzz. While researching my problem I found that the use of the cheater plug removed the buzz and it did work.

Yes, using a cheater plug is and may not the best way to go. For me I use a cheater plug for my MC205 plugged into a dedicated 20 amp circuit. I am not too kin in doing that. I do not like the fact of removing the ground plug, but it works for me. I plug and unplug my amp when not in use. Sometimes I will go 2 - 3 weeks w/o listening to my system so unplugging it is not a bad thing.

Hum X is a product that takes the buzz away for about $70. Cheater plug: $00.70.

Please let use all know what is causing your buzz and how u removed it. I am very interested to know.
Thx and good luck