Bryston just came out with an new upgraded circuit board (called IAD) for the BDP-2 USB player. This board is claimed to substantially upgrade the sound quality of the Bryston XLR/Coax digital outs.
Well, I bought and installed the board.
Now, when I play Hi Rez (at 24/192 PCM) I am getting severe distortion. I have now tried two 2 separate IAD circuit boards.
Bryston is claiming it is because of the way the PS Audio Direct Stream performs, since it doesn't use regular Dac's.
So, has as anyone successfully used the new IAD board in the Bryston BDP-2 connected via a XLR or Coax to a PS Audio Direct Stream Dac?
If you could try to describe the distortion it might help. Or if you could record it and PM a link to a recording to me that might help.
Did Bryston give any hints as to what they think we’re doing wrong? Whether the DS uses regular DACs or not can’t be an issue, but there’s a chance that between us we have a difference in the expectations of the S/PDIF and/or AES/EBU signal - some receivers accept signals without the proper framing bits for example.
What does the display on the DS show when it’s distorting?
As an experiment you might try different cables, but if you’ve already tried AES/EBU and S/PDIF this isn’t likely to make a difference.
Does 24/176.4 work?
Does the distortion depend on the DS’s volume setting?
Ted Smith said
Did Bryston give any hints as to what they think we're doing wrong?
Bryston's director of marketing indicated he would speak with their chief technical guy (who is very good) and speculated as to a possible cause: "I will ask Chris as we have a PS here - it may have something to do with the PS up-sampling everything to a very hi frequency on the input?"
I suggest first double checking the installation of the new board.
Nah, the upsampling is synchronous and has more headroom than a typical DAC so there’s no reasonable chance for overload or such. Also since 48k and 96k are upsampled to 192k the final upsampler would fail just the same on them as 192 . Even so, if someone could digitally record the 24/192k signal for me I’ll look at it and see if I have some sort of bug. I far more suspect something in the S/PDIF or AES/EBU signals, tho I don’t know what it would be.
I have now installed two separate boards and they both exhibit the distortion. The USB is unaffected, but then the new board only upgrades the XLR/Coax out. I have tried other cables and the distortion occurs when using the XLR and the Coax outs.
Sorry, but I have no way of recording the distortion. I can hear the distortion slightly with the lower resolutions but the higher ones are unbearable. The PS screen shows the correct resolution.
When I went back to the original Juli board everything plays ok. But then I have an expensive non usable trinket.
Yeah sure, I talked to Mike after I tried the first board was bad. He sent another. When I installed the second board it also had the same distortion.
Since then, Mike did not return my calls. So I asked to speak to someone else. I talked to Chris on Friday, and he said he would get back to me when he had time. I have talked to Brian also who said he is the President.
Hard to believe that both boards are defective, but stranger things happen.
I’ll repeat Elk’s question. Is there somewhere that you could connect the Bryston to another DAC’s AES/EBU or coax input to sees if this goes away? A shot in the dark would be to re-install Yale or an earlier OS version. Frustrating. Good luck.
“We’ve looked at it and it appears the ps audio dac doesn’t like the wave form produced by the IAD. Placing a probe across an xlr data pair causes the signal edge slope enough that the signal comes through much clearer, but still not perfect. Likely this issue won’t be resolved and that the IAD should be returned and refunded.”
i hadn’t thought much of it , but prior to your posting I had one album that was unplayable due to distortion.
After your posting, I checked that albums resolution and sure enough if was 24/192.
i then played the one other album I have at 24/192 and yes it too was distorted.
So for me thankfully those are my only 2 albums recorded at that Rez in my library, as every other Rez seems to work, including 24/174.
Very weird anomaly.
For me, I couldn’t’ send the IAD back because I only have 2 out 3000 albums affected by this, in contrast, i don’t have a ton but I have more than that recorded in single rate DSD which the new board now allows via AES.
I have perhaps 60+ in 24/192 so it was an issue for me. I also thought the lower Rez 24-92 also had some distortion. I guess once I heard it, I was really listening for it. I’m lucky though that I had the ability to go back to the Bryston original board. People who buy new units will not have the choice, until there is a fix.
I’m disappointed, but using the USB out from the Bryston with my 2 Regens and Jitterbugs attached is still quite the improvement.
Has anyone tested this compatibility issue between the Direct Stream and Bryston BDP-D with Huron loaded? I have a BDP_2 and would really like to upgrade the sound card to the IAD.
