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Old 16th April 2013, 12:27 PM   #11
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I am not exactly clear what the fix in #4 is...

The on the B3 and B3SE firmware remapping of inputs directs the DSD signals to the correct DACs. All 8 channels get fed a correct signal for DSD or PCM. It makes no difference.

What it sounds like you are doing is hard-wiring the DAC only for DSD input.

BTW with the experimental USB firmware I am working on I get no "pop" at all with DSD input into B3SE.

If the problem were with the playback of DSD itself you would see it from any DSD source.

The problematic bit is the fact that the DoP protocol is used, but because it is not detected for several samples the DAC (quite correctly) detects PCM (with a very loud signal).
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Old 16th April 2013, 12:40 PM   #12
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In the current implementation I switch by running all samples through a FIFO of sufficient length to detect the change before actually sending any output. This necessarily introduces a delay. In my case 32 samples.

One can fix this in the player software by making the DoP preamble look like PCM silence.
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Old 16th April 2013, 12:54 PM   #13
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BTW - If you use the Buf3 you can wire the inputs any way you like. You just need to remember that if you want to be able to play both PCM and DSD without rerouting you have to wire it the same as B3SE in any case.
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Old 16th April 2013, 01:07 PM   #14
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Also to give you an even clearer picture. In my modded Denon SACD player I simply use an OTTO-II to switch between PCM and DSD, both are routed via the teleporter to the B3SE. There are several people doing the same thing. So the issue is not in switching between PCM and DSD, it is in doing it badly. There are no issues with this approach. Changing from listening to a CD to an SACD is seamless.

I am actually not a huge fan of DoP and I may actually decide to skip it for now. I don't like the added delay and processing that doing it right entails.
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Old 16th April 2013, 11:44 PM   #15
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Quote:
Originally Posted by Russ White View Post
I am not exactly clear what the fix in #4 is...

The on the B3 and B3SE firmware remapping of inputs directs the DSD signals to the correct DACs. All 8 channels get fed a correct signal for DSD or PCM. It makes no difference.

What it sounds like you are doing is hard-wiring the DAC only for DSD input.

BTW with the experimental USB firmware I am working on I get no "pop" at all with DSD input into B3SE.

If the problem were with the playback of DSD itself you would see it from any DSD source.

The problematic bit is the fact that the DoP protocol is used, but because it is not detected for several samples the DAC (quite correctly) detects PCM (with a very loud signal).
Russ, I really appreciate your help in this matter. I have it set up for SPDIF and i2s/DSD and mostly use i2s. The player may have a lot to do with the POP and that is the reason I'm looking for a global fix. As mentioned I have one player that works fine and one that does not with the same USB interface. BTW I'm using DoP into the USB interface in both cases. Unless your experimental USB firmware also has a fix the player that does not work for me will not work for you without POPs.

Last edited by vortecjr; 16th April 2013 at 11:48 PM.
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Old 16th April 2013, 11:46 PM   #16
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Originally Posted by Russ White View Post
In the current implementation I switch by running all samples through a FIFO of sufficient length to detect the change before actually sending any output. This necessarily introduces a delay. In my case 32 samples.

One can fix this in the player software by making the DoP preamble look like PCM silence.
Understood.
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Old 16th April 2013, 11:53 PM   #17
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The DAC is behaving as it should... You are proposing hobbling the DAC for PCM for the sake of DSD. If you want to do that you can use Buffalo III. It's inputs are wide open.

I have not had any issue with any player that I have tried with my firmware so far, and I have no reason to suspect I would unless that player in faulty, in which case why would I want to use it?

I seriously doubt anyone else is doing it exactly the way I am. I wrote my own implementation.

Which player is giving you trouble?
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Old 16th April 2013, 11:54 PM   #18
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Quote:
Originally Posted by Russ White View Post
Also to give you an even clearer picture. In my modded Denon SACD player I simply use an OTTO-II to switch between PCM and DSD, both are routed via the teleporter to the B3SE. There are several people doing the same thing. So the issue is not in switching between PCM and DSD, it is in doing it badly. There are no issues with this approach. Changing from listening to a CD to an SACD is seamless.

I am actually not a huge fan of DoP and I may actually decide to skip it for now. I don't like the added delay and processing that doing it right entails.
I don't have the OTTO-II. However, I tried this test with good results: I set up SPDIF into the DAC with one computer and started playback. I then setup DSD into the DAC with another computer and started playback. I switched between the two while they were playing and it works very well. No POPs to report. If you drop DoP then two of the three operating systems will not support DSD into the Buffalo with your interface. I would encourage you to support DoP and I would not fault you for any delay that makes things right!
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Old 16th April 2013, 11:58 PM   #19
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After thinking it through I probably will support it.
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Old 17th April 2013, 12:00 AM   #20
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Quote:
Originally Posted by vortecjr View Post
I don't have the OTTO-II. However, I tried this test with good results: I set up SPDIF into the DAC with one computer and started playback. I then setup DSD into the DAC with another computer and started playback. I switched between the two while they were playing and it works very well. No POPs to report. If you drop DoP then two of the three operating systems will not support DSD into the Buffalo with your interface. I would encourage you to support DoP and I would not fault you for any delay that makes things right!
This test tells you everything you need to know.

The problem is not the transition at the DAC, the problem is the transition upstream.
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