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Rega Planar 10/Aria MC Phono Stage HUM

Hey all. I recently took delivery of a Rega Planar 10 and Aria Phono Stage. Hooked it up yesterday. Result: pretty significant MC hum. I’ve done some interwebbing on the matter and have seen the P8/Aria post at this forum, and see that the Aria seems to hum quite a bit. Most of the suggestions about fixing the issue are directed towards checking for grounding issues, etc. The rest of my system is fairly straightforward (Hegel H160 integrated; Hegel CDP4A; top shelf Supra wire) so after hooking it all up, I unhooked everything except the Aria to the amp and the speakers. Same hum, same volume. I did typical ground checks and that doesn’t seem to be the issue. I took the Aria and put it one more shelf away from the amp (as far away as the cable allows) and lo and behold the hum volume was cut in half. While at the new position, the hum would be "tolerable" at any particular music volume, it’s annoying when there’s no music signal going to the speakers. Standard light background white noise is somewhat expected, extraneous signal hum doesn’t work for me. So, if, indeed, this is a simple proximity issue (I don’t feel like buying more wire and putting the Aria across the room), is there an elegant shielding solution for the Aria? Is this an issue of Aria design (possibly an engineering "compromise" as Roy Gandy might suggest)? What are other phono stages at a similar price point ($1500ish) which perform musically as well as the Aria? I see I see the Parasound JC3 Jr might be an option. Looking forward to suggestions. Thanks!
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millercarbon's avatar
millercarbon
12,531 posts
 
I see jjss49 has activated the bat beam.

Phono noise is tough because its everywhere and so all you can do is try and track it down. In this case the OP seems to have narrowed it down to the phono stage and even understands the designer is happy with selling a poorly shielded phono stage. Well it probably sounds good on a test bench, just not in the real world.  

So the problem we think is EMI from adjacent components. You could redesign it to be properly shielded, or put the whole thing in a Faraday cage. I'd go with the Faraday cage. Search around, buy your fabric, ground it, wrap it around the phono stage, see how it works.  

What this does, the magnetic fields that are inducing hum in the stage hit the fabric and induce current in that instead, only now its harmlessly shunted to ground. As a bonus the phono stage will probably sound even better than it did before. Because stray EMI is everywhere, just not usually strong or obvious enough to bother. Might be this will work even if just used as a blanket with the phono stage placed on top. Might be something even simpler like a sheet of aluminum foil connected to ground and the phono stage on that. All these are variations on a Faraday cage. 

Tune in next week when we will discuss where the offending EMI came from. Same bat time. Same bat channel.


sumadoggie's avatar
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sumadoggie OP
62 posts
 
If everything else is unplugged/unconnected except the Aria to the integrated amp, the only thing left as the source of the hum would be the wall, yes? I turn off the Aria with everything else disconnected and the hum vanishes. Turn the Aria MC back on, viola, hum reappears (no hum with MM even with the volume cranked, just a bit of white noise). Is the Aria is picking up some stray signal (wall outlet; WiFi router)? Or is the Aria is the source of the signal? As mentioned it got quieter when moved a shelf away from the integrated? Having had a decent amount of experience with Hegels, I’d be quite surprised if it was causing a problem with another piece of equipment... but I’ve been unhappily surprised before.

millercarbon posted just before I wrote this follow-up. It does seem, even though I wish it no to be, that the Hegels emissions are inappropriately stimulating the Aria. As I mention: further the Aria from the energized Hegel, the Aria is quieter. I am interested in this Faraday experiment, and will likely do that. That said, are there other-than-Aria phonos in that price range which are "properly" shielded?
slaw's avatar
slaw
22,535 posts
 
No one should have to endure this. If Rega can’t offer a solution, they should buy the unit back.

The Faraday is a good suggestion. An inexpensive option is copper sheets available online
stereo5's avatar
stereo5
6,515 posts
 
Hence, a reason why I will not own a Rega.  Too many hum complaints.
lewm
13,445 posts
 
"Hum" is generally used to refer to a 60Hz or 120Hz pure tone. Do you really have hum or what is more loosely defined as "buzz", which is a mixture of frequencies?

Assuming this really is EMI and not a grounding problem, a Faraday cage may work, but by definition, a Faraday cage must totally surround the shielded component and be grounded. That would make it impossible or awkward to access the controls on the Rega preamplifier. If just putting the Rega on top of a shielding material works, that’s great, but it’s not a Faraday cage. Maybe easier to open up the chassis and install a shield inside, once you figure out the source. Anyway, I think this is a solvable problem and not a reason to discard the unit if you otherwise like it.
Or, if the amplifier can be shown to be the source of EMI that disturbs the Rega, it might be more practical to shield the amplifier, since you don't have to fiddle with it all the time.
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