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AUDIO FORUMS >> General Discussion and Support >> Rega tonearm acting as noise pickup antenna
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Message started by Rraymond on 06/09/16 at 13:57:31

Title: Rega tonearm acting as noise pickup antenna
Post by Rraymond on 06/09/16 at 13:57:31

I've been chasing this hum coming out my speakers for some time and finally figured it out. All of my gear is brand new as of a few months ago. There's always been noise or hum coming out the speakers when I play vinyl(cd setup channel is fine). I realized if I moved the Rega P3 further away from the TorII Jr, the noise would reduce to almost nothing. I originally thought it was my cheap Artcessories solid state preamp so I just dealt with it because I was waiting on my ZP3 to be built. Well, I got the ZP3 and still had the noise. I tried a grounded piece of steel under the TT, cheater plugs to lift the grounds of the amps and still had the noise. So I got my ohm meter out and started taking some measurements. Both the left and right channel from the cartridge read around 180 ohms and would stay steady as I moved the tone arm around. Then I checked the tonearm ground(it's supposed to be grounded to the left channel shield). At the home resting position I got about 14 ohms. When I lifted the arm and moved it away from there immediately the resistance jumped to over 1000 ohms. As I moved it toward the center of the record it sporadically jumped around 1-2k ohms. Well, this I believe is my problem. I called the Hifi store where I bought this from and the guy just couldn't believe this! So, I'm dropping it off today to have him take a look. Hopefully it's an easy fix and I can get this back home and REALLY hear the music!
Rick

Title: Re: Rega tonearm acting as noise pickup antenna
Post by Rraymond on 06/10/16 at 13:47:42

Well apparently the screw I was measuring from per the Hifi stores recommendation wasn't showing us a good reading but it seems the tonearm is grounded ok but while at the Hifi store they did say it was noisy. I left it there for them to check into it further. :-/

Title: Re: Rega tonearm acting as noise pickup antenna
Post by Archie on 06/10/16 at 17:17:16

Rraymond,

My TT channel is noisy compared to my CD channel too. I've tried increasing component separation, different ZP3 tubes and two different TTs with the same and different cartridges and I get the same result. Now I just ignore it since I can't hear it through/in the music. "Noisy" is a subjective term too so I don't know how my noise compares to your noise. When I added a ZMC1 I found I could reduce hum by switching around the grounds, but not by much. A higher output cart can help too.

I've been told that the ZP3 noise spec is actually quite high. Since Steve knows his business I'll bet that creating a quieter circuit would hurt the sound far more than the noise I hear does.

Title: Re: Rega tonearm acting as noise pickup antenna
Post by Rraymond on 06/10/16 at 20:09:21

Yeah Archie, I think in gonna have to move the TT out of my main cabinet and get a small cabinet to sit it on. The noise it's picking up is pretty obnoxious right now and kinda gets under your skin so it will be nice to get rid of it. I'm not expecting much from the Hifi store because there's likely nothing they can do so I guess the wifey will be getting to go shopping for some new furniture...lol

Title: Re: Rega tonearm acting as noise pickup antenna
Post by Lon on 06/10/16 at 20:25:22

Have you considered a wall mount shelf?

Title: Re: Rega tonearm acting as noise pickup antenna
Post by Steve Deckert on 06/10/16 at 20:32:54

Actually the noise floor of the ZP3 is quite low. To find out what the noise floor of the ZP3 is, just unplug your tone arm cables from the ZP3. Whatever sound you hear is the noise floor of the ZP3 with the tubes you have in it. Tubes can effect the noise floor, but with most tubes you can't even tell the ZP3 is turned on.

Steve

Title: Re: Rega tonearm acting as noise pickup antenna
Post by Rraymond on 06/11/16 at 15:56:20

Lon,
Yeah we considered a wall mount but because of the short 1 meter cables coming off the TT the ZP3 needs to also be near it and I don't think the noise is being picked up from that, it seems to pick it up from the TorII Jr. So we are thinking of a small open cabinet with the TT on top and the ZP3 at the very bottom. Then we can easily run cables from the ZP3 to the TorII Jr which would both be at the same height thus minimizing the cable lengths.

Steve,
Yes I totally agree that the noise floor from the ZP3 is very low. I believe this is an EMI that is passing through the air and the TT tonearm is picking it up and introducing it from that very front end point all the way down the chain into the speakers. I'm sure with some rearranging I can eliminate this noise issue. Then I can hopefully also reduce the TorII Jr power transformer vibration hum and I will have a very quiet room to enjoy all this great gear!
Rick

Title: Re: Rega tonearm acting as noise pickup antenna
Post by Lon on 06/11/16 at 15:59:37

Makes sense Rick. I've wished a few times that the Rega cables were about a half meter longer!