2. analog
  3. 159681-4466

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!
sumadoggie

Showing 2 responses by millercarbon

millercarbon's avatar
millercarbon
12,531 posts
 
Thanks for the DM. One key to preventing hum is having only one path to ground that is the same for everything. The Aria is already connected to ground via its power cord. So you connect the turntable to the ground on the Aria, and nothing else connects to that ground unless its another turntable. 

If the integrated is between the turntable and the phono stage then the phono lead has to go past it and there's a small chance it picks up hum along the way. Fooling around with phono lead routing is always a good idea. You can sometimes hear noises come and go while you're moving it, touching it, etc.  

Also, fields coming out of the integrated aren't necessarily equal in all directions, nor is the phono stage equally shielded from all directions. So there's always the chance that above it picks up noise, below it doesn't. Tracking these things down is my least favorite thing about phono, and explains why if you ever hear my system as totally to die for awesome as it sounds when playing music it would drive some guys absolutely crazy when its not. My standard is if the noise level is only about as much as groove noise then you call it good enough and get onto something else. You'll get there. 
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.


More to discover