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Post by pachieh on Feb 28, 2018 20:23:23 GMT -5
I'm trying to nail down an issue between my Denon AVR 3310CI, ARC Ref 5SE, and my Emotiva DR-3 when using the RCA pre-outs. All are plugged into a Transparent Audio Powerwave conditioner (on different isolated banks). It's a low-grade hum from my Aerial 7CC center that is the worst, although the hum is in my Aerial 6Ts too, just not as bad.
Specifically when I'm in HT mode is when it happens since it’s not using balanced XLRs all the way through.
For my L/R speakers, it’s RCAs from the Denon to the ARC (PROC input), then XLR to the DR3 (with input switch set to balanced).
For my center speaker, it’s RCA from my Denon to the DR3 (input switch set to unbalanced).
When I'm listening to 2-channel audio from my Ayre QB-9 to the ARC via XLRs (with Denon turned off), it's perfectly quiet for the 6Ts. However, the center channel still hums 'cuz the DR3 is powering all 3 channels and the feedback is coming via RCA. I will manually switch the amp input for the center channel to balanced while doing 2-channel so it's quiet...
When I switch the center to balanced, it’s obviously fine. I unplugged everything from the Denon (minus RCA preouts) and the power conditioner, but that did not fix the problem. I also tried swapping RCA cables and only going to one RCA preout on the receiver as well as removing the ARC from the chain completely for the DR3 so it only had one input for the center channel from the Denon.
I get this feeling that it may have something to do with the ARC being a 3-prong power connector and the DR-3 and Denon being 2-prong.
Thoughts? I’d like to try and fix it soon as I don’t know how long I’ll be running the Denon into the future while I want for the XMC-1 GEN 3!
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Post by goodfellas27 on Mar 1, 2018 8:58:22 GMT -5
Do you have your Wi-Fi or a wireless phone nearby? Your system might pick up noise from it.
They also have double shielded RCA cables. Might help to prevent noise from getting into your system.
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Post by pachieh on Mar 1, 2018 20:01:00 GMT -5
I have a Google WiFi puck nearby. I'll pull it out and see what happens.
My RCA cables are either Blue Jean LC-1 (double shielded) for L/R speakers, and Transparent MusicLink Plus for Center. I tried the Blue Jeans for Center and it didn't change anything.
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Post by mgbpuff on Mar 2, 2018 10:08:15 GMT -5
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Post by goodfellas27 on Mar 2, 2018 10:15:04 GMT -5
did it work? I have a Google WiFi puck nearby. I'll pull it out and see what happens. My RCA cables are either Blue Jean LC-1 (double shielded) for L/R speakers, and Transparent MusicLink Plus for Center. I tried the Blue Jeans for Center and it didn't change anything. |
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Post by pachieh on Mar 2, 2018 10:35:50 GMT -5
It did not...
I also tried leaving the Denon off, but the ARC and DR3 on. Guess what, I still have the noise. So there's something going on with the RCA precuts coming from my Denon whether the power is on or not...
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Post by mgbpuff on Mar 2, 2018 11:02:14 GMT -5
Try a ground wire between AV chassis and DR3 chassis.
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DYohn
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Post by DYohn on Mar 2, 2018 11:05:59 GMT -5
The Denon seems to be the culprit. Try touching a piece of speaker wire from a screw on the case of the amplifier to a screw on the case of the Denon. If the noise stops or reduces, the Denon is at fault. Remove all cables from it and see if the noise stops. If it does, then I suspect the internal wiring in the Denon. Get rid of it.
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Post by pachieh on Mar 2, 2018 11:15:43 GMT -5
The Denon seems to be the culprit. Try touching a piece of speaker wire from a screw on the case of the amplifier to a screw on the case of the Denon. If the noise stops or reduces, the Denon is at fault. Remove all cables from it and see if the noise stops. If it does, then I suspect the internal wiring in the Denon. Get rid of it. Cool, I'll try that later today. If this fixes it, safe to leave it in place? I can't wait to get rid of the Denon, just need Emo to release the next Gen XMC-1! |
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DYohn
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Post by DYohn on Mar 2, 2018 11:23:08 GMT -5
The Denon seems to be the culprit. Try touching a piece of speaker wire from a screw on the case of the amplifier to a screw on the case of the Denon. If the noise stops or reduces, the Denon is at fault. Remove all cables from it and see if the noise stops. If it does, then I suspect the internal wiring in the Denon. Get rid of it. Cool, I'll try that later today. If this fixes it, safe to leave it in place? I can't wait to get rid of the Denon, just need Emo to release the next Gen XMC-1! Yes it's safe. |
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Post by pachieh on Mar 4, 2018 21:35:20 GMT -5
Alright, update. Common ground using speaker cable didn't work, not even a dent. I did notice tonight during some Netflix that brighter screens made the buzzing MUCH worse. Video and audio take separate paths, HDMI from the XBOX One X to the TV and optical audio to the Denon.
I then went through and went all the way down to zero RCA connections and noticed that I still got the hum. Even with the ARC off and no XLRs plugged into the DR3, the hum was still there. Sooooo, I am not sure what the hell is going on. DR3 is plugged straight into the wall with a solid PS Audio Power Port AC outlet.
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KeithL
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Post by KeithL on Mar 5, 2018 9:59:34 GMT -5
The fact that the hum gets louder on BRIGHTER scenes is extremely suggestive - of several things - and a ground loop is NOT one of them. Lighting the screen more brightly actually consumes more power. More to the point, at many points in the circuitry, that draw varies in amplitude at the line frequency or a multiple of it. If the receiver was handling both audio and video, it would be an obvious possibility that the video was "bleeding through" into the audio. However, this isn't the case at the TV or your Denon, and the DIGITAL optical output of the source (XBox 1) shouldn't be affected. HOWEVER, it's quite possible that the TV itself is generating electrical noise, and it makes sense that, if so, this would be worse on bright scenes. This could take the form of noise being injected back into the power lines... Or it could take the form of the TV actually radiating electromagnetic noise into the air. (If the latter, airborne EMF can be picked up by both cables and equipment, or can even be picked up by the power lines through the air, at which point it ends up back on the power lines.) An easy quick test would be to see if the noise goes away when the TV screen is off. (Some TVs are worse than others, and Plasma sets are notoriously bad in this regard, but ANY TV can do it to some degree.) Alright, update. Common ground using speaker cable didn't work, not even a dent. I did notice tonight during some Netflix that brighter screens made the buzzing MUCH worse. Video and audio take separate paths, HDMI from the XBOX One X to the TV and optical audio to the Denon. I then went through and went all the way down to zero RCA connections and noticed that I still got the hum. Even with the ARC off and no XLRs plugged into the DR3, the hum was still there. Sooooo, I am not sure what the hell is going on. DR3 is plugged straight into the wall with a solid PS Audio Power Port AC outlet. |
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Post by pachieh on Mar 5, 2018 18:45:25 GMT -5
It does not go off when the TV is off. TV is a Sony XBR930D 65”. Just bought it last summer.
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DYohn
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Post by DYohn on Mar 5, 2018 18:46:24 GMT -5
I agree. You are likely not hearing a ground loop at all. You may (and I repeat MAY) have a ground voltage offset. Something like the Emotiva CM2 could help you.
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Post by pachieh on Mar 11, 2018 12:09:55 GMT -5
Alright… Here’s an update since I finally got some time to work on it…
I believe the issue is the REF5SE. When I pull it out of the system, speakers are quiet. I went RCA pre-out from the Denon straight to the amp and only had the typical very quiet hiss. As soon as I put the REF5SE back in (RCA from Denon to REF, then XLR to amp), the noise comes back.
I also pulled an older amp out for the center only (leaving the REF still in system) and went RCA to the older amp. No noise on the center channel, but low-grade hum from the L/R going through the REF.
To make sure it wasn’t the Ayre QB-9 to the REF, I unplugged the XLRs and had no change.
All connections are seated properly and everything is plugged into the PowerWave.
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Post by bluemeanies on Mar 12, 2018 9:22:43 GMT -5
Alright… Here’s an update since I finally got some time to work on it… I believe the issue is the REF5SE. When I pull it out of the system, speakers are quiet. I went RCA pre-out from the Denon straight to the amp and only had the typical very quiet hiss. As soon as I put the REF5SE back in (RCA from Denon to REF, then XLR to amp), the noise comes back. I also pulled an older amp out for the center only (leaving the REF still in system) and went RCA to the older amp. No noise on the center channel, but low-grade hum from the L/R going through the REF. To make sure it wasn’t the Ayre QB-9 to the REF, I unplugged the XLRs and had no change. All connections are seated properly and everything is plugged into the PowerWave. Pachieh...seems like you have found the problem. Anytime I had a hum...which is very frustrating I did not fool around. I torn down the whole system and one by one added each piece of equipment. Also I was conscious of the outlets I was using for that particular piece of equipment especially amplifiers. I also put a 6' ground rod outside of my house and also used a grounding wire by the water meter. One side to the other..old school...but I did it anyway. My system is very quiet. I recently introduced fault line interruptors and I was concerned that a hum would develop but it did not. BTW...My SS amplifier is plugged to the wall outlet however the m125's are connected to a kill O watt that is connected to a Variac. |
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Post by pachieh on Mar 12, 2018 19:18:50 GMT -5
Hmmmm… No success on trying a cheater plug on the REF (to remove the ground). Sound was the same with and without it. When I go PROC BAL on the REF and NO RCAs to the REF (but still RCA from Denon to the amp for center only), things are dead quiet. Only thing I can think of now are the output impedance of the Denon RCA pre-outs and input impedance requirements on the REF. It’s 60k ohms for SE on the REF, no clue on the Denon as I can’t find the specs anywhere.
It is definitely something either REF or Denon specific to the RCA plugs as you said, there’s a ground differential that I’m not sure how to solve now. It’s hard to test a 2-prong source that has XLRs since I don’t have any laying around.
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DYohn
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Post by DYohn on Mar 12, 2018 19:22:37 GMT -5
Why are you using both a preamp and a receiver?
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Post by pachieh on Mar 12, 2018 19:24:04 GMT -5
Two channel audio and home theater. I’m looking to go AVM60 (XLR everything!) in a few months as my Denon is over 10 years old now. But until then...
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Post by pachieh on Mar 12, 2018 20:59:58 GMT -5
One more food for thought. I don’t know if it’s normal behavior, but when I switch from PROC SE to PROC BAL, I still get sound through the speakers (even though nothing is plugged into the PROC XLR inputs). Same thing if I put it on VIDEO SE and go to VIDEO BAL. Kind of odd in my mind as I’d like to think those inputs are all isolated from each other and when you switch between SE/BAL on the same input, sound should disappear...
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