Dagnabbit: Audible hum and cross-talk (PrimaLuna)

[HuddieLedbetter]

Hi all,

I moved houses 6 months ago and although my setup is the exact same gear I'm now getting a noticeable hum on the system -- and if the DAC is streaming and I switch to the phono, I can now hear (with the volume turned up) whatever track is streaming. The only difference in the set up that I can think of is that I'm not 100% sure what plugs in the Panamax MR4300 went to what components -- and currently the REL sub and the Panamax are now plugged into the same outlet. In the previous house the sub and Panamax plugged into different outlets.

I also discovered something very odd -- that if an Apple lightning cable was plugged into the front charging port of the Panamax and I held the lightning connector tip in between my fingers (or pressed with one finger it against the carpet) that it would generate a loud audible hum through the speakers. (when the system was on)

The electrical in the house is only about a decade old and when we moved in I asked an electrician that was doing some work about replacing the outlet with a medical grade or audiophile outlet and he said the current outlet was fine -- and that without being able to change the electrical coming in from the street that I wasn't going to get any material gains. (downtown Boston, brownstone, not much chance of that...)

I would characterize myself as a relative idiot when it would come to anything beyond flipping a fuse in a panel for electrical. For the stereo, I'm probably just above an idiot (?) but that's only because I've had the same gear for a long time and it simply isn't that complicated getting it set up.

For quick reference:

• PrimaLuna EVO 400 amp and pre-amp. (connected via a Nordost cable that I can't remember the name of... it's blue)
• Technics SL-1210GAE (connected via a Music Hall phono cable to the pre)
• Musical Surroundings Nova III phono pre. (Zu Audio RCA interconnect to PrimaLuna)
• Oppo BDP-95. (Zu Audio RCA interconnects to the Mytek)
• Mytek Brooklyn Bridge (2nd gen?). (ZuAudio to the PrimaLuna)
• Devore Fidelity O/96, ZuAudio speaker cables
• REL Storm III Subwoofer -- connected with Neutrik cable to the speaker taps on the amp

Everything is plugged into the Panamax except the REL subwoofer. In the previous apartment the amp and pre-amp might have been plugged into the wall (though an standard surge protector) vs. the Panamax -- but I can't totally remember.

I'd welcome any thoughts -- or if there is a set of steps that I could go through to get to root cause -- otherwise it feels like I'm just going to try unplugging random things....?

Thanks all.

 

[kvetcha]

Didn't see this get posted, sorry. Have you ensured that none of your interconnects are running parallel to your power cables? Is the layout of the components any different than it was? I was getting hum with my MM carts and then realized it was RFI from my wall-mounted smart lighting fixture. So now I use MCs.

 

[HuddieLedbetter]

Didn't see this get posted, sorry. Have you ensured that none of your interconnects are running parallel to your power cables? Is the layout of the components any different than it was? I was getting hum with my MM carts and then realized it was RFI from my wall-mounted smart lighting fixture. So now I use MCs.

Thanks for the note. I’m on the road at the moment — and will actually in be back at home for only about 36 hours before getting in a plane again — but I’ll see if I can check when I get back. IIRC there “should” be separation, but perhaps not as much as in the last place. I did isolate one part from the hum down to the phono preamp. If I remove it from the stack, there is no hum on the channel with the DAC (mytek) — but that was as far as I got before feeling a bit at a loss.

 

[kvetcha]

Thanks for the note. I’m on the road at the moment — and will actually in be back at home for only about 36 hours before getting in a plane again — but I’ll see if I can check when I get back. IIRC there “should” be separation, but perhaps not as much as in the last place. I did isolate one part from the hum down to the phono preamp. If I remove it from the stack, there is no hum on the channel with the DAC (mytek) — but that was as far as I got before feeling a bit at a loss.

If all your grounds are in place and everything is routing through the power conditioner, I'm guessing hum is more likely to be coming from power cables and interconnects being too close together.

Couldn't hurt to plug your REL in elsewhere just to see if that changes anything, but I'm not sure why it would.

 

[HuddieLedbetter]

If all your grounds are in place and everything is routing through the power conditioner, I'm guessing hum is more likely to be coming from power cables and interconnects being too close together.

Couldn't hurt to plug your REL in elsewhere just to see if that changes anything, but I'm not sure why it would.

While not totally resolved, I moved the gear around — raising the phono pre amp to the same level as the turntable so that the cable lines were cleaner — retightened the grounds to the music hall cable (might replace that) — and moved the Panamax to a different shelf to also make the power cable runs less cluttered — and changed to XLR cables for the the Mytek (also ZuAudio fwiw) and it got me 88%+ there. (Very scientific figure)

The hum is no longer “ground loop hum” and there isn’t cross talk (I’m not sure if that is the xlr cables or the fact that it moved from the aux 2 slot to the aux 4 slot — phono pre is in aux 1) from streaming — but the phono pre is still no longer “silent” which is just strange to me. With the volume at listening levels there is a low level static hiss that wasn’t there before… but for now, especially as I’m getting on a plane again in 12 hours, I’m taking the win

Thanks for the revert back and offer of help. I’ll probably try tweaking the power with the sub when I get back and perhaps look at the phono pre cable. The phono pre is an open box from 2019 but I can’t see a possible reason for hiss, though perhaps something got shifted in the move. Person that didn’t just move house would rationalize buying a new one…

 

[Joe Mac]

While not totally resolved, I moved the gear around — raising the phono pre amp to the same level as the turntable so that the cable lines were cleaner — retightened the grounds to the music hall cable (might replace that) — and moved the Panamax to a different shelf to also make the power cable runs less cluttered — and changed to XLR cables for the the Mytek (also ZuAudio fwiw) and it got me 88%+ there. (Very scientific figure)

The hum is no longer “ground loop hum” and there isn’t cross talk (I’m not sure if that is the xlr cables or the fact that it moved from the aux 2 slot to the aux 4 slot — phono pre is in aux 1) from streaming — but the phono pre is still no longer “silent” which is just strange to me. With the volume at listening levels there is a low level static hiss that wasn’t there before… but for now, especially as I’m getting on a plane again in 12 hours, I’m taking the win

Thanks for the revert back and offer of help. I’ll probably try tweaking the power with the sub when I get back and perhaps look at the phono pre cable. The phono pre is an open box from 2019 but I can’t see a possible reason for hiss, though perhaps something got shifted in the move. Person that didn’t just move house would rationalize buying a new one…

I had issues with hum when I first got my PL power amp. It was a grounding issue with mine in that I had too many grounds in the system and it was causing a ground loop. I had to add an ifi GND defender to every device with an AC input apart from the preamp. That left the preamp grounding the system and solved the issue.

 

[HuddieLedbetter]

I had issues with hum when I first got my PL power amp. It was a grounding issue with mine in that I had too many grounds in the system and it was causing a ground loop. I had to add an ifi GND defender to every device with an AC input apart from the preamp. That left the preamp grounding the system and solved the issue.

I had never even heard of that -- thank you!