What Silenced the Ground Loop?


I have a ground loop in my system that is audible from the speakers as the volume is turned up higher. I have a Blue Circle integrated, and one of my sources is a Raysonic CD128. I've had the Raysonic connected single ended. I purchased an inexpensive XLR interconnect just to hear the sonic difference since my Blue Circle has balanced cd inputs and the Raysonic has xlr outputs (not truly balanced).

Once I connected the xlr cables between the Blue Circle int and the Raysonic, the ground loop is gone. Total silence. I can turn the volume on the integrated all the way up and the speakers are silent.

What is it about connecting via balanced inputs on my integrated to not truly balanced outputs on the cdp that killed the ground loop? Thanks for your thoughts
foster_9
All hums are not from ground loops. That you hum varies with volume suggests to me that it is not a 'ground loop' hum. Your RCA's output connections themselves may be causing a hum, or the tubes in the center two positions may be inducing a hum. Don't have that trouble with mine from either outputs though. FWIW.
The ground wire is connected in balanced mode on the XLR interconnects. It's likely your RCA ICs have the ground wire or shield floated at the load end. You might try switching the direction of your RCA interconnects just to hear what happens.
You might try using a cheater plug to "float" the ground at the AC plug(s) of both components; I'd also try leaving everything as is (with the RCAs connected per usual) and connect a wire between both units to effect a chassis ground. There is NO simple solution for ground loops, or differences in ground potential. Trial and error are the only sure curatives. Most can be solved with patience; some cannot. Happy hunting.

-Richard
Thanks for the feedback.(no pun intended):)
Newbee: its not the tubes in the center position of the Raysonic since I had this hum before I got the Raysonic.

Tvad: the sihgled ended IC's I use on my sources are Acoustic Zen Matrix Ref II's and are directional. I don't have enough knowledge of the cable design to know if Robert Lee designs the Matrix Ref II's with the grounds floated or not.

Directional means the ground is floated at the load end (in other words, the ground is not soldered to the RCA outer ring at the end that connects to the preamp).

Try switching the IC around and listen for any change.

Also, I'm a bit confused. You didn't have the ground loop prior to using the XLR cable, even though you were using the AZ RCA interconnect?

Do you have both ICs connected at the same time? If so, remove one or the other. I have found having both attached on my gear creates some problems that go away when just one set is connected.
Tvad: Yes, I did have the ground loop (or whatever it is)prior to connecting my Raysonic with XLR's. Using the AZ RCA's with both of my cdps I have had the hum. In fact, I've had 3 different cdps connected up with rcas' and have had hum with all 3. The only exception has been when I connected the Raysonic up to the balanced inputs on my integrated. That config has no hum.
Did you have the hum with the DK Design? Maybe it's an issue with the Blue Circle's RCA grounding scheme.

Reverse the ICs...or not.

Or stay with the balanced ICs (that's what I'd do).

The final technique is "star grounding" in which the only grounded power cord is the one attached to the preamp. The remaining power cords have floated grounds. Also, all interconnects connect to the preamp with the directional arrows pointed to the preamp, including the interconnects from the preamp to the amp.

Good luck.
No I did not have hum with the DK except when I had it connected to a particular AC regenerator I had previously. By the way, there is no problem having the rcas and xlr's connected at the same time. Each has there own sonic signature. And the xlr's are inexpensive Belden wire with Neutrik connectors(Blue Jeans), but they sound pretty darn good and aren't fully broken in yet. Thanks for the thoghts Tvad. I'll consider trying a reversal a set of the AZ's.
By the way, there is no problem having the rcas and xlr's connected at the same time.
Have you tried disconnecting the XLR pair while keeping the RCA pair connected? I am aware they each have their own sonic signature. On my present preamp, having both connected at the same time skews the right/left balance and reduces the gain. This goes away when one or the other is disconnected. I didn't learn this until I tried it. Unless you've tried it, you also won't know if it affects your system's sound.

I'll consider trying a reversal a set of the AZ's.
Foster_9 (Threads | Answers)

So I am clear, I am not suggesting another set of AZ ICs. I'm suggesting unplugging the set you own and reversing the interconnects so the ends that were connected to the source are now connected to the Blue Circle, and vice versa.

Since the only new element in your system is the Blue Circle, I'd suggest the problem likely lies there. Perhaps try lifting the ground on the power cord that you use on the Blue Circle (by using a cheater plug).
Directional means the ground is floated at the load end (in other words, the ground is not soldered to the RCA outer ring at the end that connects to the preamp).

That is incorrect. A cable can be directional if there is an outer shield that is only connected at one end but you have to have the ground (outer ring) connected at both ends. It can also be directional if there is a terminating network on one end.
A cable can be directional if there is an outer shield that is only connected at one end but you have to have the ground (outer ring) connected at both ends. It can also be directional if there is a terminating network on one end.
Herman (System | Reviews | Threads | Answers)

That's correct. That's what I intended. Thanks for the correction. A cable's directionality has to do with the shield being connected at one end and not the other.

What's important for Foster9 is that he turn his IC around to see if the hum is eliminated by doing so. Wouldn't you agree?
Also, try disconnecting the single ended ICs from both the BC and cdp. There are some preamps and integrated amps that do not like having only one input connected and will hum until one other input is connected as well. Give it a try, see what happens.
And yes, the Blue Jeans XLRs are really good. Their single ended cables are excellent as well, although not quiet as detailed and do not do the soundstaging as well as AZ Matrix Ref II.
Foster_9, did you work out your problem?

Have you experimented with your ICs?
Grant, no time for testing the cables today. I barely had a chance to do any listening. I will test them soon. As always, thanks for the suggestions. I will post my findings.