Buzzz goes the gainclone(ground loop)

I moved into a new house a couple of weeks ago. Finally got the chance to hook the gainclone up(briangt design) to the HTPC again. At my old house the gainclone worked perfectly with the HTPC.

Hooked all of my equipment up and turn on the gainclone and I am treated to a nice buzz. Just to make certain nothing had happened to the amp I tried a portable radio hooked up the gain and didn't get any buzz.

I have plugged the power cord into different outlets but haven't had any luck.

any more advice?
 
AJ Bertelson said:
this is something that I was starting to wonder also. They are the standard 3 prong outlet. How do I go about checking to see if they are properly grounded?


hmmm, i guess one way of testing if the grounds are not just floating is checking with a DMM. set it to 150VAC or more, shove one probe in the hot, one prob in the cold. you should get something near 120VAC. then just move the prob from cold to ground, and you should get the same reading. (hot is the right hole when facing a plug) if your ground isnt grounded, you wont get 120VAC.

:att'n: careful though, these are high voltages!
 
I agree with Carlos, as his point is more likely to cause a problem. The outlet ground is still important, but much less so. Relative ground is more likely the problem (most components don't have a mains ground).

The most reliable (safest) way to test is to use an outlet tester (available from home depot, etc). Plug it in to your outlet and indicator lights tell you what is wrong, or if everything is okay.

Search on "GFI-501A" onthe HopeDepot.com page. You are looking for the Gardner Bender GFCI Circuit Tester Model GFI-501A. Under $8.
 
What I mean is that if there are two components with a "safety" earth connection, there will be a ground loop.
Take for instance a preamp and a power amp, both earthed.
There will be a ground loop, noise will be very noticeable.
Because there will not be one single ground connection between the two devices, as it should be.
Ground will return to the preamp by two different paths: the interconnects AND the earth wire on the electrical system.:bawling:

I'll stay by here before I go to Texas for "safety" reasons. :xeye:
 
carlosfm said:
What I mean is that if there are two components with a "safety" earth connection, there will be a ground loop.
Take for instance a preamp and a power amp, both earthed.
There will be a ground loop, noise will be very noticeable.
Because there will not be one single ground connection between the two devices, as it should be.
Ground will return to the preamp by two different paths: the interconnects AND the earth wire on the electrical system.:bawling:

I'll stay by here before I go to Texas for "safety" reasons. :xeye:


Yes! when using true mono block the ground loop goes from either left power amp thru the speaker to the right power amp thru the speaker and back or left power amp thru the preamp to the right power amp and back :xeye:

even thru the wall ground to complete a loop via the amps
 
I have had this occur on two occasions. The first was the result of a bad solder joint on the ground shell of an interconnect wire. The other time (this might be yer problem) was a ground loop caused by components being plugged into two separate power outlets. This was causing a ground loop. I checked the outlets and they were both properly wired and solved the problem by using a three prong power adaptor on one of the component's power cords. The ground prong of the adapter was left hanging and not connected to anything. Problem solved. :D
 
I knew that would get a few interesting replies. Since no one was never shocked by any of the components in the system and I didn't have any fires, I guess I should consider myself lucky. I didn't mention that I also tried plugging things into a single power-strip (they've probably caused more fires than most people are aware of) and the darn thing still buzzed. Here's an idea- try the adapter trick to see if that is what is causing the problem. Then you can work on some type of proper repair.

I will withhold my comments on insurance company lawyers. I wonder what an insurance company would think if they had to pay for a claim that was the (accused) result of any piece of DIY audio gear? (ever looked at the disclaimers/warnings/precautions that come with a step-ladder? I'm scared to death at the thought of ever using one.):xeye: