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Not a ground loop hum???

I thought I had a ground loop hum, given that with my pre, cdp and amp all on, without any music playing, there is a hum emanating from my speakers. Following the advice seen here and elsewhere, I went out and got some cheater plugs to try and hunt down this annoying and, at times, distracting hum.

My system comprises: Anthem CD-1 (with DH-Labs power cord), Blue Circle BC21.1 tube pre (with BC62 pc), BC22 amp (Zu Cable BoK pc), Rune loudspeakers by Zu Cable (hooked up with Zu Cable Libtec speaker cable), Blue Circle MR1200 balanced power line conditioner/distributor (Zu Cable BoK pc), and van den Hul D102 MKIII interconnents.

Well, with the three components' power cord fitted with a cheater plug and all plugged into the power conditioner, the hum was still present, same intensity, volume, etc. Removing the cheater plugs one by one starting with the cdp, then pre, then amp, there was no reduction in the hum. In fact, I think I may have heard it get worse at one point.

Any ideas out there as to the cause of the hum? Maybe the tubes in the system are the culprit. There is a pair of Siemens CCa (6922 type) with Pearl tube coolers installed in the pre, and the tube in the cdp is a Telefunken CCa with a tube cooler.
mghcanuck
mghcanuck OP
116 posts
 
Sean:

Your realisation is correct, eh?! But I appreciate the humour, so no harm done. Pbb may indeed be quite ardent at times, but it probably has more to do with a feeling of inferiority due to living next to such a big and powerful and awe-inspiring and free and great and did I say powerful nation like the US, well I guess there is no "like the US" since it really is the only super-power, and that's just super IMHO, but now I'm rambling and so I'll stop. :-)

Aha, I have a multimeter! What am I measuring for? Sorry, but my electrical knowledge is, shall we say, pretty limited. I gather that the first step is to disconnect all IC's and only have one component plugged in at a time. I seem to remember you may have covered this in another thread where you had a kit that would be shipped from one A'goner to the next so they could check for polarity and difference in ground potential. Could you provide the link to that thread or instructions/advice? Thanks very much.

I am going straight to the Upscale Audio web site to look for the device you mentioned.

Max
sean
6,229 posts
 
Try this thread about Noise, hum and AC polarity. Sean
>

PS... I am by NO means a "super-patriot", but your humourous response tells me that you at least weren't offended by my crass sense of humour : )
swampwalker's avatar
swampwalker
5,132 posts
 
not meaning to hijack this thread, but I have another question about hum. When I touch the volume dial on my pre, I get a pretty significant hum, but its not there when I am not touching it. Any ideas?
sean
6,229 posts
 
Swampwalker: Your preamp is poorly designed and lacks stability. Adding the conductivity of your body to the electrical characteristics of the preamp via chassis ground is enough to alter the performance of the circuit in what is an audible manner. If audio components were properly designed, their chassis wouldn't be connected to the active circuitry in any way, shape or form. Sean
>
mghcanuck OP
116 posts
 
Sean:

Once again, you have proven to be 'da man! That's exactly the thread I had in mind. Looks like I've got some work to do. Thanks very much for your valuable input and advice.

Max

PS... I'm not offended in the least. The US and Canada, despite recent disagreements, have one of the closest relationships between nations on Earth. Some humour in the relationship can help keep it healthy. To paraphrase: "A bit of foolishness now and then is cherished by the wisest of men." Not that I'm wise, far from it, but I think the message is pretty wise itself. All the best.
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