Directstream bit rate display

I’ve just purchased a Directstream. I’m playing music off a Synology NAS via Roon (Core on a Nuc).feeding a Sonore ultraDigital into a Sonore ultraDigital into the DAC via I2S…

I’m enjoying the sound quality even though I haven’t clocked hundreds of burn-in hours.

I have noticed a couple things that puzzle me.

First, I notice that the Directstream display flashes white on and off before I even turn on the DAC. I believe I read in a forum thread that it is a quirk of the I2S connection. Is that true and more importantly is the DAC being harmed in any way?

Second, I’m feeding the DAC a bit perfect signal out of Roon (upsampling is turned off). When I play a Redbook file the DAC display shows 24 bit rather than 16 bit. I checked with Jesus at Sonore who said it might be the ultraRendu padding zeroes but he wasn’t sure about that. Has anyone out there experienced something similar?

Anyway, I’m digging the DAC… DSD sounds especially good as my old Naim DAC didn’t handle that very well.

When playing the DS counts samples per second to determine the sample rate and looks at the bottom 8 bits of each sample for non-zero bits to determine the number of bits in use.

If it says 24 bits then some bits beyond 16 are changing. That can easily happen if there’s any volume level processing upstream (perhaps a volume control or Replay Gain) or any other DSP (e.g. an EQ).

The way to tell if you indeed have a Bit Perfect connection is to run the bit perfect test with the DS. There are instructions in the manual as well as in the “How To” section of the “Resources” in the PS Audio web site.

Indeed some I2S devices provide 5V on the “5V” line, PS Audio’s spec is that the PS Audio gear does it, but that doesn’t always happen. Check with the designer of your I2S device to see if the 5V can be disabled. Some here have put a strip of tape over the 5V finger in their connector. A few others have cut the 5V either on their source, in the cable or in the DS.

Whether this hurts the I2S device or the DS depends greatly on the design of the device and precisely which voltages are on the DS and on the device. I really recommend fixing the source device. If you don’t, at least unplug the I2S device when you power the DS off. Having an external 5V source can also affect sound quality (probably for the worse.)

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I’ve got a fixed volume in my zone in Roon as I use the volume control on my external preamp. I’m not using any DSP.

I’ll download the bit perfect file and see how the DAC reacts.

As to the 5v stuff I’ll have to find someone to help me as I’m afraid I don’t understand everything you’re saying…I’m a bit of a Luddite when it comes to that stuff.

Thanks for your help Ted.

Hi Ted,

Regarding the Bit Perfect issue, I downloaded the Bit Perfect test file from the PS Audio website and played it through Sonore ultraDigital via I2S. The words “Bit Perfect” were not displayed on the Directstream.

I then played the test file through the uDigital via coax. “Bit Perfect” was displayed on the Directstream. When I played some Redbook music via coax “Bit Perfect” disappeared from the display but it did show the correct bit rate (16).

I then bypassed the ultraDigital altogether and played the test file through the Sonore ultraRendu via USB. “Bit Perfect” was displayed on the Directstream. When I played some Redbook music via coax “Bit Perfect” disappeared from the display but it did show the correct bit rate.

So the first question is should the words “Bit Perfect” be displayed when music is playing or only on the test file. I’d hate to think that there is something incorrect with my thousands of music files.

The second question is about I2S. Clearly there is a problem playing bit perfect material either out of the ultraDigital or with the I2S input of the Directstream. Can you confirm that you’ve seen the Directstream play the bit perfect test file through I2S with any equipment and had “Bit Perfect” show up on the display?

I’m trying to figure everything out while I’m still in my 30 day trial period. I’ve read in reviews both on the PS Audio forums and other sites that I2S is what makes the Directstream particularly special. Sonore and Small Green Computer both claim that the ultraDigital I2S connection works great with the Directstream.
It’s hard to imagine that everyone who has used the Sonore/PS Audio combination with I2S has missed that the signal is not bit perfect.

I will be reaching out to Sonore and Small Green Computer about this.

And just to let you know, I’m enjoying the Directstream very much. I just like to know that when I spend thousands of dollars on something that everything is working correctly.


The words Bit Perfect on the DS display only show up when playing (the 24 bit) bit perfect test files. They won’t show up if you, say, truncate to 16 bits or play any other files. The Bit Perfect test on the DS simply checks that a particular bit pattern is being played for at least a second (which is a lot of samples.) Then it goes off as soon as the pattern is interrupted.

All DS inputs support bit perfect playback (and have from the first release of the DS.) It isn’t likely that there’s anything wrong with your DS hardware or your cables.

There are many thing that can be slightly misconfigured in software on the source which can disturb bit perfect playback both in the playing program and in the OS… (Tho there should be fewer with something like the ultraDigital.) Many of these don’t affect sound quality at all (e.g. a good volume control.)

If your source says something like “Bit Perfect” that only means that that particular program thinks it’s not changing anything, it doesn’t guarantee that something else on the source machine isn’t doing something to the audio.

Thanks Ted.

I read on the forum about the Matrix X SPDIF 2 converter. It’s making me want to switch from the ultraDigital because of the issues I’m having. I read that you like the Matrix and that own one. Does it not have the 5v problem that I’m experiencing with the uDigital?

No, the Matrix does the I2S 5V the way that PS Audio likes. I’d be a little surprised that something from Sonore wouldn’t at least have an option for the 5V over the I2S, but I haven’t had one in my system for years.

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Hi Ted…Sonore is looking into the ultraDigital issues. I was asked by Jesus what pin was carrying the 5v current. Based on my online research I told him it was pin 18. Can you confirm that?

Yep 18

I purchased an HDMI adapter from Jay’s Audio in Hong Kong that blocks pin 18 (for an oppomod I2S card). It’s $30, but not on their website -you have to email.

Hi Ted,

So I returned the Sonore ultraDigital and purchased a Matrix X SPDIF 2. The good news is that the display screen flashing is gone.

I’m still getting 24bits displayed when playing redbook but I’m not concerned about that anymore as it seems like zeros are being padded and the music isn’t being harmed.

The bad news is that I’m still not getting a bit perfect signal into the DAC via I2S. I’ve confirmed this with the PS Audio bit perfect test file. I do get a bit perfect signal out of the coax port but not I2S. Both ultraDigital and Matrix have behaved this way. So doesn’t that mean that the problem is either in the HDMI cable (purchased from PS Audio) or the DAC itself?

24 bits on Redbook is also a sign that you aren’t getting bit perfect communication.

Have you tried both of the I2S inputs?

The cable probably isn’t the issue, but they don’t cost much at Staples or Amazon so you could try a different cable for just a little outlay.

I use a Matrix myself and have never had problems with I2S.

Just tried the 2nd I2S input and got the same results. I then replaced the PS Audio HDMI cable with an HDMI cable that I use in my home theater system. Still no bit perfect through I2S. Any other ideas?

Are you using an external power supply for the Matrix (instead of the USB power)?

Yes. Currently plugged into a 7v SMG LPS.

Have you tried it without the external supply?

Just tried it with no external power supply. Same result.

How are your switches set on the Matrix?

fdreed asks a good question, more details:

If the data bits are inverted you will see 24 bits for CDs (FFs in the bottom eight bits) and you will fail the bit perfect test, but things will sound fine.

If the Left/Right flag is inverted you’ll (unsurprisingly) have swapped channels.

If the bit clock is inverted thing might work perfectly, not at all and/or anywhere in between.

I use all three switches off on the Matrix.

Thank you, thank you fdreed and Ted. The Matrix I purchased was an “open box” unit. All switches were in the “on” position. I switched them all to “off” and I’m getting a bit perfect signal.
Somehow I’ve got to buy you a beer someday.