Stellar GCD and Singxer SU-1

OK, plenty of views but no responses so far in the DAC forum after 24 hours so thought I’d try asking here.

When I connect the SU-1 via coax to the SGSD this is what I see on the display:


However, when I connect via i2s (which is the reason for adding the SU-1 to the chain) the “PCM” and “44.1” lines are gone; all that remains is the filter setting. However, I do get sound through the i2s connection (and it sounds fantastic).

I also stumbled across this image from a post in the headfi forums (identical setup to mine) from March of 2017; as you can see the sample rate lines are also missing here with the i2s connection so my experience does not appear to be an isolated incident.

My SU-1 features their latest 4-way i2s circuit (versus the older lvds type). My GCD is less than two weeks old (in my system) so it should also represent the latest implemented technology from PS Audio.

I should point out one oddity I noticed when I inserted the SU-1 into the chain:

When I power on my gear, I always start at the lowest level of the chain and work my way up to the amp, which is powered on last (and reverse the process when shutting down). Being a cautious sort, I always power everything down when swapping out cables, etc. So when I inserted the SU-1 in the chain I powered that up before the DAC, but lo and behold the DAC came out of standby mode, even though the master power switch on the rear was turned off! The only way I could get the DAC to power on normally was to power it on before the SU-1. So it looks like somehow the DAC is receiving a power signal through the HDMI connector from the SU-1 sufficient to wake it from standby…that seems really bizarre but I have been able to replicate this behavior.

I have been working with Tim at Kitsune HiFi to help sort this out (and he’s been incredibly helpful) but at this point I would really like to hear from somebody at PS Audio…


Hi Ross,

I’m sorry to hear you are having issues. The SGCD should show PCM and sample rate info on the I2S input. I just verified on a unit here (not matched to the same equipment, but to a PWT transport). I will make sure one of our customer support guys reach out to you first thing tomorrow to help sort out this issue.

What is the Firmware version of your SGCD? You can find this information going through the menus (long press the button to get in the menus)


Thank you, Matt. I’ll send you the Firmware version when I get home tonight.

Here is the Firmware info:

FPGA: 1.04

Just to reiterate, the sound is fine (in fact, incredible) through the i2s input via the SU-1; it’s just that no sample rate info is shown. Here’s the display via i2s through the SU-1:


And here is the display via coax through the SU-1:


Although I can only speculate here, I’m guessing that the i2s DIP switch settings on the SU-1 for PS Audio devices were based on the DS and DSJ. Were there any changes, however, subtle, made to the i2s channel on the GCD versus the DS or DSJ?

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Hi ross254,

I forwarded your query to our full engineering team.
It will take a day for them to pour over the Singxter specs to know if this is a cause.
I’ll be able to get back to you with more information after they have had time to review.

For your review there is a great spreadsheet showing the pinout of a lot of I2S products:

The Singxer SU-1 listed among them as well.

We’ll let you know what we find.
Thanks in advance for your patience,

  • Jeremy

Great…thank you. I appreciate your looking into this.

Hi ross2509,

After looking into it a little further is seems that there indeed are differences between the Singxer pin-out and our I2S pin-out.
Clearly these differences are the culprit for why the sample rate and PCM identifiers are not being displayed.
From here there is not much more we can do.

I can contact Singxer for you if you like and inquire about their product to see if there is a solution.
That being said, you should not have any issues with performance with this information not shown.
Let me know if this is acceptable or how I can assist moving forward.

  • Jeremy
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Thanks…it’s not a show stopper since I listen almost exclusively to 44.1 material. It still sounds fantastic and as long as there are no performance issues I can live with it. Interesting though that nobody has ever commented about this behavior before, either here in the PS Audio forums or through the Singxer representative I have been corresponding with. Just another first world problem, I suppose…

Thanks again for looking into this.

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Have you compared to a good USB source?

I have an Ultrarendu but I am considering an Ultradigital to convert to I2S.

In my case I was looking for maximum flexibility with output options if I were to pair it with another DAC that didn’t have i2s, so the SU-1 was my choice.

My SU-1 features their new 4-way custom i2s circuitry (apparently all SU-1’s since around April or so of this year have this, along with some other enhancements) which supposedly offers benefits over the lvds technology. I have nothing to compare it to other than it sounds fantastic via i2s (and which may also help explain the sample rate display issue).

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I have a Matrix X SPDIF 2 available if either of you are interested in an alternatively. I used it to clean up USB from a standard PC into DirectStream and have since gone to an I2S PCIe board and new server.

PM if interested