Help, my amp is picking up radio!

[Chu]

Hello all. I recently purchased a LD2++, and there is some sort of grounding problem. There is an incredibly annoying buzzing in one of the channels, and I am pretty sure it's picking up some sort of radio signal.

The problem might be related to grounding, because when I touch a certain spot on the case (where the RCA jacks meet the case) the problem magically disapears. Just having my hand around that area helps the problem a ton.

I am trying to figure out what I have to do to fix this problem. I've read the LD2++ amp has a problem with ground hum (which seems unrelated) with the solution is to plug all the cables into the same strip, but that hasn't worked for this problem.

 

[Chu]

Oh, and I am sure this problem isn't related with the tubes. I've done some tube rolling and they all have this problem.

 

[Negatron]

If the power cord center ground pin fell off by mistake with complete disregard for all government safety regulations, which it should never do, the problem may clear up. Keep in mind without the ground pin a transformer short could put lethal voltages to the chassis. (I don't know how I have lived this long)

 

[vcoheda]

is it possible that the item is defective.

 

[3x331m]

Quote:

Originally Posted by Chu /img/forum/go_quote.gif The problem might be related to grounding, because when I touch a certain spot on the case (where the RCA jacks meet the case) the problem magically disapears. Just having my hand around that area helps the problem a ton.

The electrical wiring in your home is a giant antenna. Try to use a surge protect which has noise filter.

 

[MonolithTMA]

Quote:

Originally Posted by Chu /img/forum/go_quote.gif The problem might be related to grounding,

May I ask what you have it plugged into, wall, powerstrip etc?

 

[xnothingpoetic]

ERS paper anyone?

 

[MonolithTMA]

Quote:

Originally Posted by xnothingpoetic /img/forum/go_quote.gif ERS paper anyone?

OK, who's going to rock me to sleep tonight? I made the mistake of Googling ERS paper and found this:

ERS Paper - picture and video thread

After seeing that, I really had the urge to delete my account and never return!

Well, not really, but I did feel a bit woozy.

 

[GAD]

If you don't know who Patick is, well... let's just say there are a lot of people who don't take him too seriously.

GAD

 

[MonolithTMA]

He seemed like a very interesting character.

 

[illkemist]

My iBasso D1 was doing this the first day that I used it, but has since stopped. I don't know what corrected the issue, but I did notice that the orientation of the amp had an effect. I just turned it around and about until the sound went away.

 

[gritzcolin]

try different cables? if the same try finding some ferrite cores and put them around the cables that usually kills interference.

 

[kramer5150]

Somethings defective in the amp. Send it back to david for repair. If youre a DIY type you could open it up and check for loose ground lugs. The fact that you can touch it and it goes away makes me think the chassis is not properly earth grounded. By touching the amp chassis your body is providing an earth ground

.

 

[Negatron]

Quote:

Originally Posted by kramer5150 /img/forum/go_quote.gif <snip>... By touching the amp chassis your body is providing an earth ground .

It may be educational to drive a 10ft rod into the ground and connect a DVM between it and the 'earth' ground plug. There is usually several ohms to 'ground' and not unfrequently, voltage. By touching the chassis you also provide a high impedance ground for RF, which can ride in on the 'earth' line and radiate from the amps ground into the circuit. Audio went for around 50 years with 2 prong plugs. A power filter is a good idea before shipping off the amp, also a 2 prong 'cheater' plug adaptor is a good test. And a ferrite core on the power cord never hurts.

 

[Chu]

Looks like I spoke too soon. The cheater plug does not fix the problem. Guess ferite beads are next on the list