New SGCD loud pop/thump when changing to/from HT input?

I just received brand new SGCD today and it makes really loud pop/thump in right channel when switching between HT input or any other input. In left channel you can barely hear it - this is okay I think. This is happening only when HT pass-through is enabled and does not matter if AVR cables are connected or not.

SGCD -> XLR -> M700 -> Speakers

Tried without source cables and when I switch XLR right to left / left to right it goes to left channel. With RCA to M700 the pop/thump is even louder, almost damaging speakers!

Here is the video: https://photos.app.goo.gl/dTvyaRP2bg4yiWqp1

So I’m really sad now, what are my options? Let my dealer know and request for a replacement unit?

Edit1:
I contacted service@psaudio and found out that my SGCD has old firmware with HT pass-through bug. Nice quick answer/info, great! :+1:

Edit2:
Found more bugs. When I use regular RCA input and crank up the volume for HT AVR there are loud bangs with every increased volume step. Here is the video: https://photos.app.goo.gl/xhlVWrNRnLHI2JWE3 Another bug is volume level 1 is quite loud for evenings/late night listening sessions. Are these bugs also fixed in new firmware?

Edit3:
New firmware did not fix any of my problems and I even found more problems. When Mytek Brooklyn is playing on analog input 1 I can hear it quietly on the background from input 2 and 3.

Now it is clear that my SGCD is faulty and dealer accepted to replace it. I hope this is a final edit of this post. :slight_smile:

Edit4 19.06.2018:

I received the replacement unit and it has exactly the same problem as my first unit. It seems to me that DC is building up (when digital source is playing on coax or usb) in output capacitor and when I switch inputs the capacitor is discharged (I measured max 180mV) into output. But I don’t get it how this can be only in right channel in two separate units.

My dealer tested it for a week and told me that this is not SGCD’s problem, the problem is in my home probably with ground. I have dedicated line from circuit braker to rack. All my gear is grounded in the same power strip.

So after a month of finding a solution to use AV Receiver with Stellar Gain Cell DAC I would not recommend to buy SGCD for this purpose!

Edit 13.03.2019:

So 8 months later I’m still having this problem and it seems to me that right channel gain cell module is faulty. I have tried everything and I’m out of ideas. I really like how this DAC sounds and it is hard to say this it is my last PS Audio gear I buy, because my dealer won’t help me either, I’m alone with my SGCD. :frowning:

Hi @spezwend,

I appreciate all the great work you’ve done troubleshooting this problem - I understand how frustrating things like this can be and I want to help you get to the bottom of it.

I had a long conversation with one of software engineers and the designer of the Stellar amps about this and we would like to have our engineering team look over your Gain Cell DAC if possible.

If you wouldn’t mind, send me an email at scott.schroeder@psaudio.com and we’ll get the process started.

Thanks again for your patience - I’ll make sure we get to the bottom of this.

Hi @Schroedster,

Thanks for your interest about this problem. How long this process will take? When do you make sure we get to the bottom of this? How long will this take? Two months? Six months? Why are you ignoring my e-mails? My patience is coming to an end soon.

Ignoring problems seems PS Audio way of handling things. I sent an e-mail about it @Paul (Sun, 19 Aug 2018) still no answer.


I made some videos about DC offset on both channels and I want share these. If a engineer see this, please comment about it. It does not seem okay behavior to me.

Left multimeter is left channel and right multimeter is right channel.

I am sorry no one is responding to you. That is certainly not our way. In fact, quite the opposite.

Scott and I are at the show in Chicago. I am answering every email I receive on the day I receive them, 7 days a week.

I do not respond to PMs.

If you actually email me at
paul@psaudio.com you will get a response from me. If you don’t it may be because the system has flagged your email as SPAM or some such.

Worst case, please pick up the phone. 1-800 PSAUDIO

Hi @Paul,

Thank you for your reply. I know you answer but that’s it. I writed about this: On Aug 19, 2018, at 6:26 AM and you replied to me:


On Sun, 19 Aug 2018 at 3:50 PM, Paul McGowan paul@psaudio.com wrote:
Thanks. I was unaware of this problem. Let me check and get back to you.


Paul McGowan | CEO | PS Audio
4826 Sterling Drive, Boulder, CO 80301 |
Ph 1-720-406-8946 | Fax 720-406-8967 |


And nothing more, exactly like Scott 4 weeks ago. :frowning:

Hi Spezwend,

I’m sorry for not getting back to you. I passed your measurements over to our engineering team, though we lost track of this while they were working on the AN3 speakers for Axpona. We didn’t provide the high level of service we hold ourselves to and I’m sorry about that.

I sat down with our engineering team today and we have identified the problem you encountered. @tomgPS will be developing a fix. Once we have it ready, we will send you the PIC chip with the new firmware.

I just got the same Stellar Stack as you and am very very happy with it. I do experience mild thumps when changing inputs or changing music tracks. But I have A LOT of modifications (crap) going in and out of my Stellar Stack. No buzzes, and I only hear hiss at 100…LOL. The DAC is amazing though.

Because the thumps do not occur during playback through of any of the inputs, I can live with this minor nuisance. Won’t damage my Speakers.

I’m good.

Do You use HT passthrough? It’s happening only with HT passthrough enabled input and after 20-30min of digital input playback. And only on the right channel. Left is quiet like it should be. Look at this video and turn up the volume:

It’s like someone hits you with boxing glove into chest. The bass drivers never move so much with music, even with bass heavy music.

I agree with you, the DAC sounds good. I’ve already sold my Mytek Brooklyn DAC. To be honest, this HT Passthrough is the only reason I bought the SGCD on first place but after listening it for some time I really like the sound of it.


Thread update: After a year my SGCD is going back to PS Audio for RMA.

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Yeah, I looked at it earlier and it is nasty. I can’t use the Home Theater input in my PS Audio/Sony/Bose setup. Because I hacked 5.1 fixed level true balanced outputs out of my Sony AVR, it bypasses the AVR’s internal volume control but not any of it’s other audio functions. With some other DIY hacks (see my posts in the “Do It Yourself” category), I have a very nice sounding, clean, psuedo true balanced interconnect layout, and no noise (other than the odd thumps…but I don’t believe in my case it’s a PS Audio issue. I adjusted the center and surrounds using the AVR’s internal amp’s to match the dB level produced by the Stellar Stack. I can actually dial the same volume “number” on both the SGCD/Preamp & the Sony STR-DN1080 and everything blends together nicely. 5.1 SACD’s, DSD files, DVD & BluRay Audio Discs, Concerts, and movies all sound so much better after carefully integration of everything mentioned above.

After a month I got my SGCD back from the PS Audio. They changed everything they told me, but the problem still exist. So there is a problem with the hardware. I have tested 3 different SGCD’s now and all have the exact same problem - a loud thump from the right speaker when switching to Home Theater passthrough mode from digital input.

Found one more case like this:

Sorry to hear you are still having issues. They should have been resolved before sending your SGCD (or replacement) back to you. I don’t use the HT setting. However, I have a similar, but much smaller, issue happening with my SGCD.

Probably unrelated - I get a small thump from the right speaker whenever I pull my headphone plug out of my SGCD. My headphones are very efficient so the SGCD volume is very low (usually under 10). The thump is very mild.

Weird that both issues create a thump only in the right speaker.

@JRSBat Can you please test your SGCDs HT passthrough?

  1. Just enable HT pass from the menu with volume set to 76
  2. Let any digital input play for 15 minutes at volume 10-15
  3. Switch to HT pass enabled input
  4. Do you hear a loud thump from the right speaker?

Thanks!

spezwend YUP - definite thump in the right speaker when switching to HT bypass! The thump was about as loud as in the above video. I put the speaker covers back on a few days ago so I could not see what happened to the speaker drivers.

The thump was louder than the right speaker thump I hear when I unplug my headphones.

Thanks @JRSBat! The thump goes louder every minute you play the music. After about 30min it is the loudest as it gets.

At the moment I have tested 3 different SGCDs and all of them have this problem.
+1 @JRSBat’s SGCD New SGCD loud pop/thump when changing to/from HT input?
+1 @lcouplinverizon-net’s SGCD Stellar DAC/Pre Home Theater switching
+1 @Rudolf_Appel’s SGCD Stellar Gain Cell DAC Experience

So total 6 faulty units I know of.

I wanted share a Paul’s e-mail to me that there is nothing wrong with the SGCD’s. :open_mouth:

On Fri, 31 May 2019 at 01:39, Paul McGowan paul@psaudio.com wrote:

I have gone through all the engineering documents, the three units you sent us, the programming changes made to make it better, and the test results. From all I can see, there’s nothing wrong with the units.

Thus, the problem is something we cannot solve for you. It may be simply an incompatibility with your system, which is odd because we have never encountered this in any of the hundreds of units in the field.

I wish there was more we can do, but alas, there is not. We are at a dead end.

Unbelievable! Paul always says to use your ears to judge equipment but now he uses his eyes and documents only. :frowning:


If anyone reads this post and owns a SGCD - please test it and post the results here.

  1. Just enable HT bypass from the menu with volume set to 76
  2. Let any digital input play for 15…30 minutes at volume 10-15
  3. Switch to HT bypass enabled input
  4. Do you hear a loud thump from the right speaker?

Hi @spezwend, please allow me to correct, I encountered the thump inserting the headphone jack.

I will test the HT input switching with the Audio Quest silence caps on the RCA inputs and report back.

I’d like to add, my unit sounds very good, I am happy how it makes my Yamaha active speakers sing.

Maybe, you tried this already, please do not take this offensive:

  • Plug the SHCD into the same power bar as the HT receiver
  • Having Dome the above, reversing the power plug of your HT receiver / controller.
  • Another option could be, in case that receiver has no ground wire in it’s power supply cable, to consider to add a ground lead from your receiver chassis to the earth where the power plugs are connected.

Since you assume that a DC voltage is building up, which I imagine is a plausible cause, since the thump tends to get louder, it might have to do with the power supply of any of the apparatus.

Anyway, I’ll test my SGCD as mentioned above and report back to this thread.

Absolutely yes Rudolf, my SGCD sounds very good also but it’s about the HT bypass and preamp. It seems to me that the only option is to use two different sets, one for stereo listening and one for Home Theater. You can not use SGCD in the chain! I’m considering to buy another real preamp and use SGCD only as a DAC. A working preamp that has input relays, no input crosstalk, no pops on volume control and working HT bypass.

This thump happens even with AVR/HT Receiver disconnected. I have one “audiophile” power strip where all my gear is connected. I’m not assuming about the DC voltage, I have measured and made a video while measuring. If you are interested check my videos linked above. I have tried many different players also and one at the time for testing and the result is the same.

Please Rudolf test your SGCD, I’m just trying to prove that this is a larger problem probably hundreds faulty units out there not just with couple of SGCD’s I have tried.

I saw the video. I will test my SGCD and let you know. Still I would not exclude software issues, everything is Micro Processor controlled.

Excellent plan Mr S!!

A real pre-amp that has volume recall per input. Just set the volume of the input that will be assigned as a HT bypass to 0.0 dB, and every time you select that input it will be in HT bypass mode. With no thumps in the speakers to cause any aggravation.

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Actually SGCD does have kinda same feature but only for one analog (1-3) input and it’s the main reason I bought it on the first place and second I already had M700s.