Denon X3800H / Classe Audio CA-5200 - Ground Loop through RCA-cables?

[Hobolicious]

Or for piece of mind, grab a 200/300 8/4 ohms amp from Audiohphonic, Nord kind of class D amps for the LCR and let the AVR power the remaining speakers, and then just enjoy the music.

How would I know I would not experience similar issues with these power amplifiers as I have with the Classé and Parasound? Ordering Audiophonic, Nord, Apollon or similar would likely have to be done from abroad, so if I did experience similar issues returning it would be a pain (also custom costs will be quite significant).

 

[PENG]

How would I know I would not experience similar issues with these power amplifiers as I have with the Classé and Parasound? Ordering Audiophonic, Nord, Apollon or similar would likely have to be done from abroad, so if I did experience similar issues returning it would be a pain (also custom costs will be quite significant).

If I remember right you just need a 2 channel amp to power one of your surround/height/Atmos channels so why not just buy a $89 Fosi or similar class C chip amp and be done with it. If that hum, that I doubt very much, just send it back with a good reason (assuming you buy from Amazon.com).

There is nothing wrong with those mini chip amps, they sound as good as the Parasound to me ears and mic. Hard to believe but true, people just can't shake their Placebo prone ears/brains (too me a long time too...).

The much more costly way is of course to buy from Audiophonic, Nord, Apollon etc., and if you experience similar issue then just use their return policy, but yes you may be subject to custom cost if your country is not part of the EU, but is it?).

So I really thing you should try the Fosi amp first as that would limit your potential loss in shipping/custom costs. If still get the hum then you really should try the Benchmark RCA to XLR cable and see if it works with the Classe, I still think even that cheap Monolith or Ghant Audio pairs will.

 

[Hobolicious]

Hello again,

I decided to go back to basics just to make sure I am not missing something. Below is a step by step guide as to what I have done:

1. I unplugged everything from the power circuit, as well as unplugged everything except for speaker wires from the Denon X3800H (AVR from now on) and Classé Audio CA-5200 (Amp from now on). Meaning the only connections on the back of these two units currently were for the AVR 8 sets of speaker wires (surrounds and Atmos) and an unplugged power cord, and for the Amp 3 sets of speaker wires (fronts and center) and an unplugged power cord. PS! For reference the power cord of the AVR is Type C and therefore ungrounded, while the power cord of the Amp is Type E and therefore grounded.
2. I connected the Amp to the power socket and turned it on. I would categorize the sound coming from the fronts and center as normal noise floor of the Amp (a very slight noise/sound when moving very close to the speakers). All good so far.
3. I connected the AVR to the same power socket as the Amp and turned it on. No changes to the level of noise coming out of the fronts and center, and the remaining 8 speakers did not have any noteworthy noise/sound being output.
4. I then connected a RCA-RCA cable from the center pre-out stage of the AVR to the Amp. I started of by only turning on the Amp and now the center speaker was outputting what I assume to be a ground loop noise. I then turned on the AVR and the sound level of this noise through the center speaker increased (the noise from the fronts and remaining speakers were the same as previously).
5. Out of curiosity I then connected another RCA-RCA from the front right pre-out stage of the AVR to the Amp. Same issue as in number 4. where the FR speaker was also outputting the noise.
6. Also connected the third RCA-RCA from front left pre-out stage of the AVR to the Amp. Again same issue with all three speakers outputting the noise.
7. I then unplugged the Amp and tested with another Power Amplifier (the Parasound Halo A31). Starting of with no connections between the Parasound and AVR there were no noteworthy sound/noise being output by the fronts and center.
8. Before I go any further it is important to note I left the gain knobs on the back of the Parasound at 12 o’clock. When connecting the pre-out for the center speaker I did not seem to catch a big difference in noise. This was with the same RCA-RCA cables.
9. I then connected the front right (as well as the center) pre-outs and now the sound level was much higher (not as bad as for the Classé, but unsure if this just has to do with the gain settings or not).
10. I finally connected all RCA-RCA cables between the AVR and the Parasound and the noise level was quite similar as in 9., just across all three speakers. Again, substantially lower than the Classè, but still present at the MLP.
11. I then went over to testing the other cables I have available, that being Cordial RCA-XLR cables and the RCA-XLR cables TLS Guy made and sent me.
12. On the Parasound the Cordial RCA-XLR cables seemed to have the best performance in terms of noise level (I would say it was barely there). These cables also worked the best on the Classé, BUT introduced a different issue with clicking/popping noise from the speakers (not extremely loud by any means, but definitely something I could notice), this did not seem to be the case with the same cables connected to the Parasound.
13. As for the RCA-XLR cables TLS Guy provided me with they unfortunately seemed to fair equal or worse than the RCA-RCA cables.
14. While doing some of the above tests I did try touching a speaker wire between bare metal on the two chassis and it definitely has a positive impact on the noise level (lowering the noise). It varies a bit between the different cables. I have tested this to a larger extent previously with the Classé and it did not remove all the noise. From the very slim testing with this speaker wire between the AVR and Parasound it did potentially seem like the effect was even better (potentially lowering the noise to a level where it was not noticeable anymore). I will have to test this further, but I probably need to do a full calibration with the Parasound connected as I have not done that as of yet (to see how this impacts the noise level after the calibration has been performed, if at all).
15. I have not yet connected anything else to the AVR, but what would be connected to it is as followed:

• PS5 (not grounded) through HDMI
• Apple TV 4K (not grounded) through HDMI
• LG OLED C2 (not grounded) through HDMI
• Panasonic UB9000 (not grounded) through HDMI
• 2 x B&W DB1 (both grounded) through RCA-RCA
• TP-Link TL-SG108 (not grounded) through Ethernet (this one will also be connected with other of the above electronic devices through Ethernet cables and it is in turn connected to an Orbi RBK853 access point —> Another TP-Link hub —> Orbi RBK853 Main Node)
• Mini jack between AVR and Amp for 12V trigger
• Probably speaker wire between AVR chassis and Amp chassis

 

[highfigh]

Aside all the points PENG mentioned, there's no guarantee there won't be a ground issue with that used Parasound amp, and you would be right back in the same boat. FWIW, I just ordered a Fosi ZA3 the other day for my own experimentation.

If someone has a grounding problem with the A21, something is wrong- that amp has a ground lift switch.

 

[ban25]

If someone has a grounding problem with the A21, something is wrong- that amp has a ground lift switch.

That would be a good thing for @Hobolicious to check...

 

[Hobolicious]

If someone has a grounding problem with the A21, something is wrong- that amp has a ground lift switch.

Hmm, I must be blind… I can’t seem to find anything about this in the manual of the Parasound A31. What am I missing?

 

[highfigh]

Hmm, I must be blind… I can’t seem to find anything about this in the manual of the Parasound A31. What am I missing?

IO thought it was an A21.....I wonder why they would include it on some models and not others?

 

[highfigh]

I thought it was an A21.....I wonder why they would include it on some models and not others?

 

[Hobolicious]

IO thought it was an A21.....I wonder why they would include it on some models and not others?

No worries. To give a brief update:

1. I continued my testing by hooking up all of the previously listed units to the AVR.
2. After this I connected the Parasound to the AVR through the RCA-RCA cables, as well as connecting a speaker wire between the chassis of the two units. Doing the latter did have a positive effect on the noise level, but unfortunately not to the extent that it was not bothersome anymore.
3. I then swapped the RCA-RCA cables with the RCA-XLR cables from Cordial and still leaving the speaker wire connected between the two chassis. Suddenly almost all noise from the speakers were gone (you can hear a very slight sound, but only when being very close to the speakers). This was with the «normal» gain settings on the Parasound (set to 12 o’clock). Obviously cables and audio artifacts are not always easy to explain the outcome of, but with this setup I was not getting the popping/clicking noises that I was getting with the same setup connected to the Classé (as mentioned in 12. in my previous post).
4. Because of this I decided to do a full calibration with the setup in 3. and from the little I have been able to test after performing the calibration things seem to be a lot better.

A follow-up question to this: Is it fine to keep a speaker wire connected between the metal chassis of the Denon X3800H and the Parasound A31? Can there be any danger involved in such a setup?

 

[PENG]

Hmm, I must be blind… I can’t seem to find anything about this in the manual of the Parasound A31. What am I missing?

If you cannot find then it means it does not have it. The A21 has it, but I don't know if it works as I never had ground loop hum when using that amp. It may help depending on the kind of "ground loop", so there is no guarantee. It is up to you to take that chance to find out, if it work, great, if not, you have to ship that 80 lb box back right? IMO, potentially better solutions (no guarantee either) have been suggested, but it's your decision.

 

[highfigh]

If you cannot find then it means it does not have it. The A21 has it, but I don't know if it works as I never had ground loop hum when using that amp. It may help depending on the kind of "ground loop", so there is no guarantee. It is up to you to take that chance to find out, if it work, great, if not, you have to ship that 80 lb box back right? IMO, potentially better solutions (no guarantee either) have been suggested, but it's your decision.

I looked at the photos when I saw the switch on the A21, but that was yesterday and I didn't sleep great the night before, needed my coffee, suit didn't come back from the cleaners, etc.

 

[highfigh]

No worries. To give a brief update:

1. I continued my testing by hooking up all of the previously listed units to the AVR.
2. After this I connected the Parasound to the AVR through the RCA-RCA cables, as well as connecting a speaker wire between the chassis of the two units. Doing the latter did have a positive effect on the noise level, but unfortunately not to the extent that it was not bothersome anymore.
3. I then swapped the RCA-RCA cables with the RCA-XLR cables from Cordial and still leaving the speaker wire connected between the two chassis. Suddenly almost all noise from the speakers were gone (you can hear a very slight sound, but only when being very close to the speakers). This was with the «normal» gain settings on the Parasound (set to 12 o’clock). Obviously cables and audio artifacts are not always easy to explain the outcome of, but with this setup I was not getting the popping/clicking noises that I was getting with the same setup connected to the Classé (as mentioned in 12. in my previous post).
4. Because of this I decided to do a full calibration with the setup in 3. and from the little I have been able to test after performing the calibration things seem to be a lot better.

A follow-up question to this: Is it fine to keep a speaker wire connected between the metal chassis of the Denon X3800H and the Parasound A31? Can there be any danger involved in such a setup?

When I have dealt with noise problems, I check for voltage between the pieces of equipment- that shows electrical wiring problems. Then, I make sure all of the connections are snug, to make sure noise is rejected and the shielding can do its job- I found a loose Y cord last week in a system I had installed 14 years ago and the noise showed up recently. I had replaced the cable box on a lower shelf and didn't need to change any cabling and checked the speakers that ended up being affected and didn't hear anything but maybe it just needed a little more time for the weight of some cables to separate the two.

Electrical problems can also cause damage to equipment when the voltage is high enough. In the US, a common cause of this is from cable installers not grounding their feed adequately, if they do it at all. If you use cable TV, I would disconnect their feed, but make sure to use only one hand- if your other hand is touching grounded equipment, you can be shocked.

 

[Eppie]

A follow-up question to this: Is it fine to keep a speaker wire connected between the metal chassis of the Denon X3800H and the Parasound A31? Can there be any danger involved in such a setup?

That might be better answered by @TLS Guy since the wiring standards are different from North America. Highfigh beat me to it, but I was going to mention measuring the voltage between the chasis without the grounding wire attached. If it's under 2V I would think that you're fine. Just be wary of rotating the power plugs by 90 degrees in the outlets as that might affect things.

 

[highfigh]

That might be better answered by @TLS Guy since the wiring standards are different from North America. Highfigh beat me to it, but I was going to mention measuring the voltage between the chasis without the grounding wire attached. If it's under 2V I would think that you're fine. Just be wary of rotating the power plugs by 90 degrees in the outlets as that might affect things.

2V is still too much and I think the plugs can only be rotated 180 degrees.

 

[Hobolicious]

That might be better answered by @TLS Guy since the wiring standards are different from North America. Highfigh beat me to it, but I was going to mention measuring the voltage between the chasis without the grounding wire attached. If it's under 2V I would think that you're fine. Just be wary of rotating the power plugs by 90 degrees in the outlets as that might affect things.

2V is still too much and I think the plugs can only be rotated 180 degrees.

I did try to use a multimeter between the chassis of the Denon and Parasound (without the speaker/ground wire being connected) and it seemed like there was very little movement on the indicator (0.1-0.2V). I assume then it should be fine to continue with having the wire connected between the two chassis and just be happy with the setup?

 

[PENG]

Hello again,

I decided to go back to basics just to make sure I am not missing something. Below is a step by step guide as to what I have done:

1. I unplugged everything from the power circuit, as well as unplugged everything except for speaker wires from the Denon X3800H (AVR from now on) and Classé Audio CA-5200 (Amp from now on). Meaning the only connections on the back of these two units currently were for the AVR 8 sets of speaker wires (surrounds and Atmos) and an unplugged power cord, and for the Amp 3 sets of speaker wires (fronts and center) and an unplugged power cord. PS! For reference the power cord of the AVR is Type C and therefore ungrounded, while the power cord of the Amp is Type E and therefore grounded.
2. I connected the Amp to the power socket and turned it on. I would categorize the sound coming from the fronts and center as normal noise floor of the Amp (a very slight noise/sound when moving very close to the speakers). All good so far.
3. I connected the AVR to the same power socket as the Amp and turned it on. No changes to the level of noise coming out of the fronts and center, and the remaining 8 speakers did not have any noteworthy noise/sound being output.
4. I then connected a RCA-RCA cable from the center pre-out stage of the AVR to the Amp. I started of by only turning on the Amp and now the center speaker was outputting what I assume to be a ground loop noise. I then turned on the AVR and the sound level of this noise through the center speaker increased (the noise from the fronts and remaining speakers were the same as previously).
5. Out of curiosity I then connected another RCA-RCA from the front right pre-out stage of the AVR to the Amp. Same issue as in number 4. where the FR speaker was also outputting the noise.
6. Also connected the third RCA-RCA from front left pre-out stage of the AVR to the Amp. Again same issue with all three speakers outputting the noise.
7. I then unplugged the Amp and tested with another Power Amplifier (the Parasound Halo A31). Starting of with no connections between the Parasound and AVR there were no noteworthy sound/noise being output by the fronts and center.
8. Before I go any further it is important to note I left the gain knobs on the back of the Parasound at 12 o’clock. When connecting the pre-out for the center speaker I did not seem to catch a big difference in noise. This was with the same RCA-RCA cables.
9. I then connected the front right (as well as the center) pre-outs and now the sound level was much higher (not as bad as for the Classé, but unsure if this just has to do with the gain settings or not).
10. I finally connected all RCA-RCA cables between the AVR and the Parasound and the noise level was quite similar as in 9., just across all three speakers. Again, substantially lower than the Classè, but still present at the MLP.
11. I then went over to testing the other cables I have available, that being Cordial RCA-XLR cables and the RCA-XLR cables TLS Guy made and sent me.
12. On the Parasound the Cordial RCA-XLR cables seemed to have the best performance in terms of noise level (I would say it was barely there). These cables also worked the best on the Classé, BUT introduced a different issue with clicking/popping noise from the speakers (not extremely loud by any means, but definitely something I could notice), this did not seem to be the case with the same cables connected to the Parasound.
13. As for the RCA-XLR cables TLS Guy provided me with they unfortunately seemed to fair equal or worse than the RCA-RCA cables.
14. While doing some of the above tests I did try touching a speaker wire between bare metal on the two chassis and it definitely has a positive impact on the noise level (lowering the noise). It varies a bit between the different cables. I have tested this to a larger extent previously with the Classé and it did not remove all the noise. From the very slim testing with this speaker wire between the AVR and Parasound it did potentially seem like the effect was even better (potentially lowering the noise to a level where it was not noticeable anymore). I will have to test this further, but I probably need to do a full calibration with the Parasound connected as I have not done that as of yet (to see how this impacts the noise level after the calibration has been performed, if at all).
15. I have not yet connected anything else to the AVR, but what would be connected to it is as followed:

• PS5 (not grounded) through HDMI
• Apple TV 4K (not grounded) through HDMI
• LG OLED C2 (not grounded) through HDMI
• Panasonic UB9000 (not grounded) through HDMI
• 2 x B&W DB1 (both grounded) through RCA-RCA
• TP-Link TL-SG108 (not grounded) through Ethernet (this one will also be connected with other of the above electronic devices through Ethernet cables and it is in turn connected to an Orbi RBK853 access point —> Another TP-Link hub —> Orbi RBK853 Main Node)
• Mini jack between AVR and Amp for 12V trigger
• Probably speaker wire between AVR chassis and Amp chassis

I would repeat, connecting a cable between the two chassis usually would not work, though in some cases it would help as it depend on the nature of the "ground loop" that varies from case to case.

Your best bet is to try one of those cheap mini class D amp, there is now one that measured even better, definitely way better than the Classe and Parasound, though the A31 should be good enough, more than good enough.

Fosi Audio V3 Mono Amplifier Review | Audio Science Review (ASR) Forum

SNR 119.6 dB, full bandwidth!! Has both XLR and RCA inputs too.

 

[Eppie]

Sorry, I meant 180 degrees not 90. Yes, I would think that 0.1-0.2V would be ok but the Fosi amps are still a good inexpensive alternative.

 

[PENG]

1. Before I go any further it is important to note I left the gain knobs on the back of the Parasound at 12 o’clock. When connecting the pre-out for the center speaker I did not seem to catch a big difference in noise. This was with the same RCA-RCA cables.

With the Parasound's gain turned down, of course you will get lower noise level, at the expense of the preamp's output that means you have to turn the volume up higher to make up the difference. The newer Denon AVRs typically have very good SNR so that is a good thing.

 

[Lapppt]

Had somehow similar issue for two/three months. Humming noise from the subs. Very annoying. Tried everything possible but the hum won't go away. It turned out these expensive SVS subwoofer cables were the culprit. I replaced them with some cheaper subs cables bought from a guy on Ebay and the hum disappeared.