[johnvin01]

I have class D amps. Love the sound , but am having some interference.
 Last night after listening to a few CDs I started shutting down my system. The hiss and buzz were present. Through my mid range I could actually hear a country music song. Lyrics clear as a bell but very low volume, but only in my right channel. After about ten seconds it turned into distortion. Usually the distortion sounds like muffled vocals but last night was audible.

I have been having this issue for a few months now.
I even added a Panamax m5300pm and no change
My system runs off a 50a sub panel and with only three outlet circuits. two run my equipment
I have disconnected the cable box and move amps.
Bought an outlet tester and its wired correctly
This happens even with the amps disconnected from the preamp

Any help on this would be great.

And there is absolutely no way anyone in this house was listening to country music. Not knocking it just would never happen.
Thanks in advance

[johnvin01]

I just did a little test. Its 6am. My house is dead quiet , no kids gaming, hvac system not running so I figured what the hell. I went and turned on my right channel and still the noise. BUT, when I disconnected the RCA from the back it got much louder. Almost as if the opening was now letting the amp receive the noise signal. Im stumped

[JohnR]

Um, what amp is it?

[johnvin01]

I wanted to keep it under wraps since I love the amps and the customer service has been outstanding. Even to the point of extending my trial period due to this issue.
But anyhow, they are Red Dragon M500MKIIs

[avahifi]

Any chance you have a nearby radio station?

It is possible that you are picking up RFI from your speaker wires.  If they are conventional two conductor speaker wires try twisting them three turns per foot in an electric drill. This will provide some self shielding from RFI pickup and often helps this issue.

Frank Van Alstine

[johnvin01]

No radio station and i have tried with different speaker wire and the same results.

[Mike Nomad]

johnvin01,

I have the same problem, with a plain ol' SS amp. Across different speaker cables. Across different speakers. And my problem started within the last few months. The transmission tower for the station I am picking up is nowhere near me.

Your amp is probably not the problem.

The problem may be that the station is broadcasting out of spec. They will swear up and down that there gear is behaving correctly. Pursuing them will be a waste of your time, and the FCC doesn't care.

The problem is (at least in part) that you have something (or things) that are behaving as an antenna (possibly powered). So, a list of checks, some of which you may already have done &/ are already handled:

/ Assuming you have three-prong outlets.

/ Check ground. Put a volt meter to the wall outlet(s): Red lead to hot on the socket, Black lead to ground on the socket. You should get 115 to 125 volts. Then put Red lead to neutral on the socket, Black lead to ground on the socket. You should get at most a couple of volts, if any.

/ Speaker wire, interconnects, power cords: None should be resting on each other. Coiled excess cable (especially speaker cable) is a big no-no.

/ Speaker cable should be shielded and grounded. [Edit - Sorry, late night, and being rather sloppy while in cut-and-paste mode]

/ Interconnects should be shielded and grounded.

/ Power cords should be shielded and grounded.

[guest61169]

Have you tested both circuits separately, plugging everything into same circuit?

[johnvin01]

I have tested just about everything.
outlet ground and polarity, speaker cable, interconnects/ makes the noise even when the amps are disconnected from the pre amp, power cords switched, my poor wife spent time on her cell turing lights and electronics on and off while I listened, brought amp two floors down and some noise but not the radio reception/  it doesn't happen all the time.
yesterday morning when I pulled the RCAs out of the back of the amp the noise got worse


last night I switched amps and I had a very very slight hiss in my tweeters, but thats normal. Ryan from RD has offered to check out the amps. My must say, their customer service has been above and beyond. I hope its not the amp because I would hate to see them go

[JLM]

I had the same issue from a nearby radio station with a DIY chip amp a friend had me try out (and even with a separate power supply it had a horrible 60 Hz hum too).

[barrows]

Short the inputs to your amp and then test.  This will tell you if the noise is coming in from the input of the amp.  If you still have the problem with shorted inputs, then the speaker cable is likely acting as an antenna.
If the noise is gone with shorted inputs, then it is likely that the noise is coming into the input of the amp.  If your amp has balanced inputs, try using them and see what happens.  If you have no balanced source, still use the balanced inputs but make a cable with RCA plugs on the source end and XLR on the amp end.  XLR pin 2 goes to RCA center pin, XLR pin 3 goes to RCA shield, and XLR pin 1 (shield) goes to shield.  Or use an XLR cable with an RCA-XLR adapter (Cardas has these) at the source end.
Also, make sure you are using shielded interconnects.

[Wayner]

Does your system also include a TV antenna?

[johnvin01]

no, just cable. I even disconnect the cable box to see what happens

[dB Cooper]

In the Mesozoic era, I used to live close enough to a college radio station that with a good set of binoculars I could have told you what color shirt the DJ was wearing. My Dynaco system didn't have a problem, but my next door neighbor did, and the station sent somebody out who installed a "trap" of some kind somewhere in their system. Of course that was back when stations had engineers in the building. Don't know if that is true anyore. But if you know what the station is, it may be worth a call.

[Mark Korda]

Hi Jonvin01, A few years ago I rebuilt a Dynaco ST-35 watt tube amp. I followed the manual to a tee. When every thing was a go I powered it up. Pat Boone (April Love) came out of my amp, slightly distorted but Pat Boone for sure. Funny thing was I had no tuner or cd player or anything hooked up. I had the old power cord,2 prong, and my wires were home made Radio Shack hook up wire twisted like Frank VanAlStine suggested,they look like Mapleshade wires. They are twisted every 2 inches so as not to act like an antenna. I could not solve the problem so I sent it to Frank VanAlStine. The problem was that when I installed the new gold RCA jacks (input),  I forgot to ground them. Dynas old crappy jacks were grounded to the chassis, physically with no wires. I also bought the amp on Ebay and assumed the tubes were correct, I couldn't see the lettering. They were not so Frank sold me the right ones. The amps been singing beautifully ever since. Frank or his team also said I had a couple cold solder joints, you may want to jiggle the wires and look for shiny solder joints not grainy. And that was the cure. Al my caps were brand new and resistors also. If this doesn't help you may need Alan Hale Jr, the skipper, to punch your amp like he was going to do to Gilligan's mouth to shut off the radio within! Good luck.....Mark Korda

[johnvin01]

Mark,
Thanks for the info. I have a feeling its not my amps, though moving them to another location did get the same results. Jut not as loud. Im goin to have to really look into the electrical source and see whats what.
Thanks to everyone for the input. Its been a great help

[johnvin01]

    so its not my amps!!. Today I switched amp and used my 3 channel for the mains , and guess what?, more country music. Weird thing is the song played and slowly diminished until there was nothing. Wish I had my phone. It was clear as day.
Worse thing is this is a new issue. My dedicated room has been in existence for years. Years of great listening. Now what?
This is driving me mad

[Big Red Machine]

This is a question:  isn't the ability to pick up their frequency related to the length of your "antenna"?  Shouldn't you try different length cabling to jump out of their frequency range?

[Doublej]

I wonder if putting ferrite filters the various cables would help you locate the source of the issue.

http://www.ebay.com/itm/10pcs-TDK-5mm-Clip-On-EMI-RFI-Filter-Snap-Around-Ferrite-NEW-/261056060985?pt=LH_DefaultDomain_0&hash=item3cc8275e39

[johnvin01]

Sounds like a good option if all else fails.

So after thinking this out, my plan of attack is to dismantle the whole system. Slowly reintroduce each component. Im going back to bare bones. CDP , Pre, and my amps. If at that point I still hear Marty Stuart, I will give up on my "hobby". Or obsession as my family calls it.