EMI/RF interference of phono stage

jbiswas1

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May 29, 2022
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I recently opted for a separate tube phono stage instead of the phono stage in my integrated amp, and I'm getting a popping noise from my speakers. Grounded everything in my rack, tried the three prong to two prong trick, tried switching out the cables to balanced cables, changed the tubes to good clean NOS tubes..tried moving things away from typical noise sources...no avail. Just wondering if any of you have built a Faraday cage for your equipment for preventing RF/EMI. This is driving me crazy. The phono stage operates flawlessly with no noise in another system...so I know that it is not the phono stage itself. Next stop ; get dedicated 20Amp circuit setup for the system to plug in to.
Connection Path: Rega P10/Apheta 3 Turntable --> Luxman EQ-500 phono stage --> Luxman L-509x Integrated Amp --> B&W 803D Speaker(and Rel T7i Subwoofer)

Looking forward to any experiences that you guys have on this matter.
 

Yelamanchili manohar

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Hi biswas :)

I just wrote a lengthy reply, and it vanished due to my poor connectivity, before I could post it :(

1. Please place your ear really close to the tweeter. If you hear something like church bells ringing, while the mid and bass drivers are still emitting popping sounds. Then it is definitely the tubes, somewhere in the chain. Either they have drifted, or you have to bias your amps again.

I will try to post this bit first...if it goes through, I will follow up with further things to check :D

Okay the above went through successfully :D

1. I had similar issues, when I powered my chain from 2 different wall sockets. I've moved everything to the same wall socket now,
2. If it is a ground loop, then you will have a constant hum at 60hz in usa. 50hz in india. And the hum will be independent of wether you are playing music, or the volume on your preamp. It will be a constant buzz. So try disconnecting one component at a time, to see which component is picking up enough Emi/RF to cause the popping.
3. My cables ( Hifidelity HT-CR1 ) though being the most transparent I've heard, are very very susceptible to pick up noise from closely placed power cables. So please check your cabling to be sure.

All the best and best regards
Y.Manohar
 

arj

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I recently opted for a separate tube phono stage instead of the phono stage in my integrated amp, and I'm getting a popping noise from my speakers. Grounded everything in my rack, tried the three prong to two prong trick, tried switching out the cables to balanced cables, changed the tubes to good clean NOS tubes..tried moving things away from typical noise sources...no avail. Just wondering if any of you have built a Faraday cage for your equipment for preventing RF/EMI. This is driving me crazy. The phono stage operates flawlessly with no noise in another system...so I know that it is not the phono stage itself. Next stop ; get dedicated 20Amp circuit setup for the system to plug in to.
Connection Path: Rega P10/Apheta 3 Turntable --> Luxman EQ-500 phono stage --> Luxman L-509x Integrated Amp --> B&W 803D Speaker(and Rel T7i Subwoofer)

Looking forward to any experiences that you guys have on this matter.
Do you have a common ground for your Phono and amp ?if not try touching the cases of both at the same time with 2 ends of any cable to see an impact.

Additionally Does the volume of the noise increase when you increase the volume control ? Also are your TT to phono cables Shielded ?
 

jbiswas1

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Joined
May 29, 2022
Messages
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Location
Houston, TX
Do you have a common ground for your Phono and amp ?if not try touching the cases of both at the same time with 2 ends of any cable to see an impact.

Additionally Does the volume of the noise increase when you increase the volume control ? Also are your TT to phono cables Shielded ?
Thanks for the insights. The other system where it was playing well, ..next day that started buzzing too. So I called Luxman and they said it might be the tubes. Lo and behold it was a rectifier tube(yes you heard it right) that was possibly going bad and was not feeding the amplification circuit right. Grounded the phono stage with my preamp and I'm good...
JIt
 
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