Speaker buzz/hum when unbalanced

[Elsiejr]

I've lived with this for a while, but thought I'd post for suggestons. My set-up is a C-2 Pre/pro, Marantz SA-11S1 SACD player connected via balanced inputs, a Denon DVD 5910 connected via RCA inputs or coax. My main amp is a Pass Labs X-250 and front speakers are Revel Ultima Studios.

When I set the C-2 for balanced inputs (to play CD's & SACDs on the SA-11S1), the system is very quite - no buzz or hum through the speakers. However, when I switch to coax or the RCA inputs to listen to CDs or play DVDs, there is a signifivant buzz/humm heard through the speakers. This is not affected by the volume control, and happens whether the 5910 is connected or not. I have tried different power cables & removing the grounding pin on either the C-2 or the amp, but it makes no difference. I have also tried unhooking the input from the cable system as I have seen that it is often the cause.

Does anyone have any suggestions? Many thanks. Maybe I just have a noisy C-2 (except when balanced)...

[blownrx7]

Elsiejr,
I could be wrong but something doesn't sound right with the C2.

I have a C1 with a 5910 with the Parasound A51 and also a Proceed Amp5.
NO HUM. The C1 and C2 are identical as far as grounding is concerned so...

Something to try: run a ground wire from the chassis (just undo one of the chasssis screws if there is no dedicated ground lug) of the X-250 to the chassis of the C2 and/or the 5910 (try all combos) and see if it does anything.
HTH

[Peter Nielsen]

Do you have anything else connected in the system that you forgot to mention? Cable box, projector?

Disconnect everything and see if you can get the C2 and SA-11S1 to play without hum (using RCA and a pair of headphones plugged into the C2). If this works, then connect your power amp. If it's still good, then keep connecting one unit after the other until you find the offending piece.

If you can't get the C2 and SA-11S1 to work completely standalone, THEN something probably isn't right...

Peter

[RJKuzma]

Same here!

This is exactly the same problem I have with my C1. When using the unbalanced inputs, including the 7.1 pure analog inputs, I get a low level buzzing at the output. This problem has existed since I purchased the unit new in 2003, but I always attributed it to a noisy AC power line or a heretofore unsolvable ground loop problem in my system. The buzzing is constant in volume (it doesn’t get louder as the volume goes up), and it is usually masked by the signal at high volume levels. It sounds like a power-line buzz and its harmonics. I have tried three different high-end power conditioning products to eliminate the buzz (including the PS Audio Premier power regenerator), but none have had any effect. The buzzing is most noticeable when all 7 surround channels are active. However, I believe this is simply because seven speakers, each producing the buzzing sound, are simply louder than just two speakers producing the buzzing sound. On multichannel DVD-Audio or SACD discs; when the volume is low or the music is between tracks, the buzz is very noticeable and distracting.
I recently purchased the Halo D3 disc player, and for the first time was able to utilize the balanced inputs on the C1. Using these balanced inputs totally eliminated the buzzing noise in two-channel mode, as long as the DSP was bypassed. If the routing of the balanced inputs goes to the DSP, the buzz returns. Also, even when the balanced inputs are selected in Bypass mode, the buzzing is still emitted from the other five connected surround outputs. Using any of the unbalanced inputs produces the buzzing in all seven of the main and surround speakers.
Since I was reconfiguring my system with the new addition of the D3, I decided to try to track down the presumed ground loop. I connected just my two JC1 power amps to the C1, and switched between the various inputs. Everything was plugged into the same power strip. Still, the buzzing was apparent on every input except the balanced bypassed inputs. Interestingly, when using the headphone jack, the analog 7.1 inputs are extremely quiet, and then the unbalanced inputs are next in quietness, with the balanced analog inputs the least quiet (probably due to the 6 dB level increase).
The only truly quiet mode I can obtain is by using the balanced inputs in “Bypass” mode, and turning off the surround channel amplifier to the surround and center speakers. My experimentation with various configurations leads me to believe that the C1 is generating this noise, and that it is not a ground loop problem. Now that I have tested for and eliminated any ground loop possibilities, I am rather unhappy with this noisy performance.
Perhaps some electronic part is out of spec, or some solder joint has too much resistance. Whatever the reason, for products in this price range, this type of noise is unacceptable. I had cheap surround receivers that were much quieter than this, and once I realized that it wasn’t due to a ground loop, I called Parasound Tech support to get a RMA, so they could look at the problem. Tony, the Tech support person at Parasound said he would test my unit to see if it is within specs. My RMA unit arrived at Parasound today, so perhaps I’ll have more information soon. I’m also curious if others who own the C1 or C2 have experienced this problem, and are just putting up with it, as we did.

[Peter Nielsen]

What power amp are you using? Balanced or RCA? Sounds like lowering the gain to the power amp might help (switching to balanced would do this by 4dB). If your amp has input gain controls, turn them down a notch.

Peter

[RJKuzma]

Peter, I'm not sure if your question was intended for me or Elsiejr.
In my case, the power amps are Halo JC1s at the front, and the Halo A52 for the center and surrounds. Everything connected after the C1 is via balanced XLR--all AudioQuest Jaguar. I even tried using unbalanced RCA, both before and after the C1, but there was no change. I also tried repositioning all my input cables, as well as my speaker cables (bi-wired AudioQuest CV-6s to Vandersteen Model 5As) just in case it was picking up some EM interference; but again, there was no change. Although lowering the surround amplifier's input gain (if possible) might help a bit, it doesn't get to the core problem, since this noise shouldn't be there at all. The more important point is that this background buzz seems to slightly interact with and modulate the audio signal. The difference in clairty and soundstage focus is significant between the balanced inputs without the noise and the unbalanced inputs with the noise. Had I not purchased a component that used the balanced inputs, I would have never known just how good the C1 and JC1s can sound.
My money $$$ is on a defective part or cold solder joint. This is literally true, since my C1 is one month beyond the 5 year labor warranty. Plus, I had to spend $50 to have FedEx ship it across S.F. Bay, since Parasound doesn't accept local walk-ins anymore. The only reason I didn't do something about this earlier is that I really thought I had created a noise-causing ground loop, as everything is enclosed in an elaborate home entertainment system on multiple AC circuits. Plus, when I turn the system up, the sound is masked--so I lived with it. When I checked this forum for similar problems, I couldn't find anything. When I finally tested specifically for ground loops, as I described in my above post, it came up negative. It's an amazing coincidence that Elsiejr's thread was posted to this forum only a day after I sent my C1 back to Parasound Service! I should have posted this here years ago; but then, it may be a very limited condition affecting only a few units. I'll wait for the verdict from Parasound Service, but I'm sure it's not normal.

[Peter Nielsen]

I agree. The C1 with JC-1 should sound the same regardless if balanced or unbalanced inputs is used on the C1. Probably a bad ground connection for the RCAs or something...

Peter

[Elsiejr]

Thanks for the ideas. As an FYI, my X-250 is connected via balanced cables as well. I tried a couple of the easy suggestions this afternoon, including running a grounding wire between the components & disconnecting some of the inputs & listening through the headphone out. (BTW – the headphone output is nice and quiet under all circumstances). This was to no avail. I’ll spend more time on it over the next few days as Peter suggests, isolating it all the way down, but I have my doubts. Since the balanced inputs are dead silent, and I do most of my serious listening (CD & SACD) using them, I never worried about it too much. But the other evening, listening to a relatively quiet DVD, the buzz/hum was annoying. I certainly look forward to what RJKuzma hears from Parasound!

[Bassman]

I've been a lurker for a long time and have decided to add my 2 cents to the conversation about buzzing problems with my C1.

If I remember correctly I had this same problem early on with my C1. It wasn't a loud buzz but it was unaccepatable to me.

I contacted Parasound about it ( don't remember with whom I spoke) and the suggestion was made that a ribbon cable inside the the unit was routed incorrectly. I was given instructions on what cable to look for and where to move it.

At the time it seemed to make a difference although now if I place my ear up close to a speaker there is a low level "noise" that I frankly havn't taken the time to track down. I come home from work, power up the system and enjoy about an hour of "chill" with my favorite CD or multichannel discs- no time for teaking.

I hope my experience helps.

I have 12volt trigger issues that I will need coaching with on another thread.

[Clive]

Have you tried lifting the ground? Would an ground Isolator on the RCA line be of any help? Just a thought

[RJKuzma]

Hi Clive; and thanks for the thoughts and interest. Although I didn't report it in my original post, I tried lifting the ground switches on the connected JC1 and A52 amplifiers as the first step. Doing this seemed to decrease the amplitude of the buzz by about ten percent. This small but significant finding was instrumental in forming my original belief that the noise issue was somehow "grounding-related." When I attempted to diagnose the cause of the noise, the only conclusion I couldn't readily make, was that it wasn't caused by a ground-loop issue. Then, after I finally got around to taking the necessary steps to determine with confidence that the noise was not caused by a system ground loop (see above postings for rationale), it seemed likely that the ground-loop-like noise problem must be within the C1 itself.

At this point in the thread, it seems apparent that this problem is not simply my unique concern with the C1/C2. At least two owners of C1/C2 units do not see this problem at all. And, at least three us have had similar problems. This controller should produce only a trivial amount of dispersed frequency noise on all of its audio outputs (as indicated by its excellent S/N specifications). Power line hum, if not caused by system ground loops, should never be apparent or acceptable. When it is obviously apparent (as in the systems of Elsiejr, Bassman, and myself), it usually indicates an electronic component malfunction, unexpected electro-magnetic induction interaction, or internal grounding problem. I am now only a hobbyist, and not an electrical engineer; but I think that minus system ground loops, this symptom is indicative of the above mentioned possible internal circuit problems. As such, a band-aid solution should not be necessary. Thankfully, due to the existence of this forum, we can assess information from others, and come to a much more precise judgment than we ever could on our own. So far, my best guess is that my C1 is malfunctioning. If it isn’t, then I am a very dissatisfied customer, because the surround audio experience is decidedly “un-High-Fidelity!” The amount of noise I experience is reminiscent of my 1973 Capehart “quad-synthesized” console (my first electronic purchase; from K-Mart, no less). I’m pretty sure that Parasound Service will arrive at the same conclusion, and remedy the problem. Either way, I’ll be sure to let other club members know of the outcome. Thanks for your input; and I love your signature phrase. It’s what we’re all trying for; and sometimes achieve.

[bigburner]

Hi RJKuzma,

To eliminate the obvious, can you please confirm that all of your interconnects are physically separated from your power cables?

I had a nasty buzz/hum that drove me to distraction looking for (non-existent) ground loops until I rewired my whole system to separate my interconnects from my power cables.

Silence ever since.

Nigel.

[iiaudio]

Have you tried different sets of unbalanced cables? Some "Hi-End" cables have the signal ground lifted for some stupid reason.

[mikepinkerton]

I had problems with hum, even with a wire connecting my sat box and my A51 until I bought one of these:

http://www.zzounds.com/item--EBTHUMX

Now everything is dead quiet. It's wonderful! Note I have a Denon 4802 for pre/pro, not a C1, but it still may be of use.

-Mike

[RJKuzma]

Thanks for the suggestions, but alas, I tried them all to no avail. As I indicated in my original post, I fully disassembled my system and reconnected only the C1 and JC1 power amps to my speakers. In doing this, I also made sure that the power cords were well separated from the interconnects.
I also tried substituting my normal AudioQuest cables with Tara Labs RSC and BetterCables Silver interconnects. Nothing changed the buzz. Also, the AudioQuest cables fortunately do not lift the signal ground.
In searching for other possible ground loops, I also tried disconnecting the power cord from my Vandersteen 5A's built-in sub-woofer amps. Again, the buzz continued. Lastly, at some point a few years ago, I also tried the Hum-X product, but it didn't help.
All of this has led me to believe that the problem must be caused by something out of spec, or insufficiently grounded within the C1. When I substituted my older Musical Fidelity 3CR preamp into the system, everything was again quiet.
Thanks for all the suggestions anyway; multiple perspectives often lead to some new insight. I plan on following up with Tony at Parasound today, to see how his investigation is going.

[RJKuzma]

97% Improved

I received my C1 back from Parasound Service today. I wasn't expecting it back so soon, as I had just sent Tony a follow-up email. Anyway, I appreciate the extremely fast turn-around. The buzzing noise is mostly gone. I would estimate that it is about 10 to 15 dB lower than before, which is certainly acceptable. A small residual amount remains, but I have to put my ear right up to the speakers to hear it now. The service record indicated that a wiring harness was repositioned. Also, it said that all current factory software and hardware updates were installed. I'm not sure what that means since I have already installed all software patches provided on the Parasound web site. I guess its just standard procedure. Regardless, it is now functioning within the acceptable range, and I can now fully enjoy surround sound without the annoying background buzz. The balanced inputs are still totally quiet, so I'll be using them for serious stereo listening. I am also happy to report that Parasound fixed it without charge, even though the five-year labor warranty had expired a month ago. :T Again thanks to everyone for your input. It looks like Bassman called it right. Perhaps Elsiejr can call Parasound and have them explain the procedure to reposition the wiring harness, so he can save on the shipping costs to RMA his C2 back to Parasound.

[Elsiejr]

RJKuzma, that's terrific news! I'll follow-up with Parasound & let you know the results. Again, thanks to all for the suggestions!

[blownrx7]

Low level c1/C2 hum problem solved?

:dothewave: Bassman,
Perhaps you could post the procedure to route the harness properly. Pictures would be especially helpful here!!!

Elsiejr,
Since they gave the instructions to Bassman a while back, there should be no problem getting them again from Parasound. Even if Bassman posts it, I recommend asking Parasound anyway. You never know if they came up with improvements or just may explain it better this time around.

IF we get something detailed enough, perhaps we could ask the moderator to sticky it at the top of the forum?

[Chris D]

Sure... I'll make anything "sticky" that warrants the appropriate attention.

Bassman-- Hey, welcome to the Guide and Club Parasound! (officially) :banana:

RJKuzma - Yikes, you've been having all sorts of electronic "queertrons". Will like to hear your thoughts after you get some time to run your equipment through the paces again. Did you send in your 3rd D3, too?

The thing that's interesting about all you guys is that the unbalanced jacks are usually the "QUIETER" of the two, compared to balanced, when you're talking about the multichannel pre-outs, usually used to go to the amps. This is the first I've heard of issues with the inputs varying.

[RJKuzma]

Chris, I didn't return the third D3 yet. Other than the weird problem of not switching layers correctly between SACD and CD, it appears to operate correctly. I think I live with it for another week before deciding. I'm not using the MultiWave feature of the PS Audio Premier this time though.
Anyhow, since a lot of people have been asking for some information on how the D3 performs, I thought I would post a comparison between it and my other components. I'll post that under a new thread sometime in the near future.
Your comment about the unbalanced jacks usually being quieter is news to me. If all else is working properly, there shouldn't be a difference between the two, provided that very long unbalanced interconnect cables don't pick up electromagnetic interference. Of course, the balanced outputs usually have twice the voltage of unbalanced, so both the signal and noise will be louder; but once you adjust for sensitivity, everything should equal out. Have you tried both the unbalanced and balanced outputs to the amps and heard a difference after adjusting for sensitivity?

[gianni]

Hmmm...interesting. Although this may seem unrelated and even be dismissed by the Halo crowd as not deserving any attention, a while back I posted regarding a Parasound Zamp with the same buzz.

In search of solutions I tried all the common fixes including power conditioners, none of which worked. I suspected the amp from day one as I have had lots of other gear from Rotel, Primare, Denon and never had the slightest problem in this house with AC noise.

I noticed that connecting an ipod directly to the Zamp with a 3.5mm to RCA cable eliminated the noise even with the ipod off. All other sources connected to the amp with various interconnects buzzed. Something about the ipod setup was killing the noise which appeared to be getting into the amp through the RCA line inputs.

As this setup was being used for a small bedroom sub/sat system, I eventually got around to installing a couple of line level RCA high pass filters. These were directly connected to the amp RCA in's and the ipod cable would connect to them. Out of curiosity I powered up the amp prior to connecting the ipod. These filters also totally eliminated the buzzing from the amp.

Long story short: is there something in some of these Parasound products topology that makes them prone to picking up noise at the RCA inputs? I would be curious to see if owners of the discussed pre's are able to eliminate the noise by connecting an ipod or high pass filters to the offending line inputs. Yes they are different components but it may yield some clues.

[Chris D]

RJKuzma, there has been a couple threads in the Club here discussing the balanced vs. unbalanced pre-outs. The balanced outs have a +6 gain, that some people have found to introduce noise when using sensitive speakers. I previously was using highly efficient Klipsch speakers, so I didn't even try the balanced. I now am using M&K's, so I'm in the process of switching to balanced and seeing what happens.

[mikepinkerton]

Sigh, adding my PS3 (connected via component) introduced more hum that the HumX can't fix. I had to defeat the ground on the ps3 at the surge protector to get it to stop. The protector itself has a ground, but that still seems dangerous.

What is it with this amp that loves to hum?
-Mike

[Pookie007]

I had a hum problem with my Parasound amp. I put a cheater on the power cable where it connected to the line conditioner and there was no hum. I eventually found the noise was entering through the cable TV connection. But a cheater plug that removed the ground from your power cord might solve your problem.

[Peter Nielsen]

If you have a cable box in your system, I stongly recommend a Jensen VRD-1FF cable isolator (~$50): http://jensentransformers.com/iso_vid.html



In 99% of cases the Jensen cable isolator takes care of any CATV box issues. Note that a cable isolator IS NOT the same as the cable surge protection on a power conditioner. The latter usually only provides surge protection and grounds the cable - which sometimes make hum issues even worse (a noisy incoming cable ground can contaminate your otherwise clean electrical ground). Surge protection is of course nice, but nevertheless you'd still want to isolate the incoming cable ground from your system ground to avoid any issues with hum. So even if you have a power conditioner, put a VRD-1FF between the conditioner cable input and your incoming cable connection. Without conditioner, put the VRD-1FF between the incoming cable and the first device (usually cable box).

Then there's the other problem with powering equipment from multiple circuits (for instance a projector and/or powered speakers/subs that cannot be plugged in the same circuit as the rest of the HT equipment due to distance). The by far easiest fix for that is to use cheater plugs on all these remote devices, but only when needed. (Note the emphasis on easy. Usually a cheater plug is safe, but if you have a powered speaker enclosed in aluminum, it would of course not be safe to use a cheater plug. Common sense must be used to determine if a cheater plug is safe or not).

Peter

[mikepinkerton]

Yeah, those isolators don't work for satellite, IIRC. Maybe I'm remembering incorrectly. I can understand the odd grounding for the sat box from the dish, etc, but the PS3 is a mystery as to why I have to cheat the ground on it.

One solution would be to give up on this component madness and buy a Parasound pre/pro with HDMI....oh wait.
-Mike

[Pookie007]

I was able to use the cable filter on my power conditioner to remove the hum, but the cheater plug is a much cheaper option. It cost me $0.49. The neutral in the plug is just to keep the component from floating. I don't know the situation where that would be a concern with a typical HT application. If you plug your components into a common power conditioner or power strip they are all connected to the same phase of power in your house. So what would happen between the power cable on the component housing that could cause the component to float relative to the surrounding components?

The Jensen box is definitely a great option, but the cheater is the cheap option.

[Peter Nielsen]

Yeah, those isolators don't work for satellite, IIRC.

Correct. They are for cable only. (And cable is usually the big problem, as you share grounding points with your cable company - you don't have control over that).


Peter

[Peter Nielsen]

I was able to use the cable filter on my power conditioner to remove the hum

Yes, this usually works fine if you have a good ground in your electical system. (Older houses/apartments may not work that well and the problem may actually get worse as you route the cable through the conditioner).

Peter

[Chris D]

One solution would be to give up on this component madness and buy a Parasound pre/pro with HDMI....oh wait.

Ah, yes, but that's right! If we just "wait"...

[Elsiejr]

Hum/Buzz resolution

I want to thank everyone for your excellent suggestions & recommendations. I finally had time to try a few things, as well as to disconnect everything from the system and start from scratch. Because the Jensen transformer was priced right & easy to implement, I tried that first, but it didn't help. (I am glad to have it as I'm sure it will come in handy in the future!).

First I disconnected the C-2 and tried it on a different 2 channel system upstairs (unbalanced inputs and outputs). It was nice & quiet...so I was back to suspecting some sort of ground loop. I put it back into my HT system and began reconnecting, one cable at a time, inputs and amps. It turned out the culprit was one of my two Bryston power amps driving my surround speakers. Bryston has a ground lift switch which I engaged, and 90% of the problem was solved.

I still don’t really understand why that was the cause of the problem…but it’s a good lesson learned, and I’m back to being happy with the C-2!

Again, thanks to all.

[Peter Nielsen]

Bryston has a ground lift switch which I engaged, and 90% of the problem was solved.

You might what to pick up one of these $0.99 cheater plugs for your Bryston.

I think the official name is something like "grounded plug adapter". You'll find them at Lowe's Hardware or Home Depot.

You can also find them at Radio Shack for a few bucks more ($4.99 for a 2-pack): Grounded Plug Adapter Catalog #: 61-2720

Peter

[Elsiejr]

Excellent - will do!