My new noDAC 0.5V ready for assembly. Next week some testing with audiolinux OS.
SAC Thailand TVC is external and used as preamplifier.
USB isolation is made with Gefen ethernet extender and a CAT 7 cable (100 m max), tested working fine up to DSD512. You can see last version here:
Gefen, LLC - USB 2.0 Extender
SAC Thailand TVC is external and used as preamplifier.
USB isolation is made with Gefen ethernet extender and a CAT 7 cable (100 m max), tested working fine up to DSD512. You can see last version here:
Gefen, LLC - USB 2.0 Extender
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
This might be of interest to some;
http://www.diyaudio.com/forums/twisted-pear/258254-support-botic-linux-driver-172.html#post4751947
The PCM/DSD outputs from the Beaglebone Black are passed to an Acko SO3 Isolator/Reclocker board, thence to the DAC, in this case a Buffalo IIIse.
The only downside is that DSD256 seems a little marginal with the Linux build I've used but as its a standard 'off the shelf' linux image that might be addressed with some tweaking?
Ray
http://www.diyaudio.com/forums/twisted-pear/258254-support-botic-linux-driver-172.html#post4751947
The PCM/DSD outputs from the Beaglebone Black are passed to an Acko SO3 Isolator/Reclocker board, thence to the DAC, in this case a Buffalo IIIse.
The only downside is that DSD256 seems a little marginal with the Linux build I've used but as its a standard 'off the shelf' linux image that might be addressed with some tweaking?
Ray
DC Offset solution
I'm finally listening to music from the JLSounds board using an interface board of my own design coupled through a 1uf/47K 4Hz HPF to remove the DC offset to a dual high frequency op amp to drive the digital signal through a 390ohm/10nf LPF. Below is the DC Removal Op Amp RC Filter circuit and some chassis/PCB pictures. The output of the op amp is directly connected to the RCA output jacks. Analog Devices recommends this 350Mhz op amp for use as a digital clock fan-out device.
It sounded good to start with except for some hiss like that heard on a radio station. I replaced the USB 5V power with a 2amp Belleson Vreg on my JLS interface board and the sound became magical except for continued light hissing. The bass is tight and deep. Voices sound natural. Percussion is precise. Music flows with a rich texture that is unfatiguing. And this is using JRiver in Windows 8 at 1XDSD dop from 44/16 source material so there is room for improvement.
About the hissing sound. Because a relay to switch between DSD signals being present or not seemed clunky to me I designed a JLS interface board to switch to a 3Mhz square wave derived from the Pin 20 12Mhz signal from the JLS board when there is no DSD signal. There is no hiss at all with this simulated DSD signal representing a 0 volt analog signal. I can see this square wave on a scope going into and out of the op amp, but with no hiss. When I switch to music I get hiss. Any ideas? Could it be the JLSounds board?
I am also having problems with occasional snapping sounds at 1XDSD but are very frequent at 2XDSD. I have version 2 of this interface board coming in shortly which might solve the snapping sounds.
I'm finally listening to music from the JLSounds board using an interface board of my own design coupled through a 1uf/47K 4Hz HPF to remove the DC offset to a dual high frequency op amp to drive the digital signal through a 390ohm/10nf LPF. Below is the DC Removal Op Amp RC Filter circuit and some chassis/PCB pictures. The output of the op amp is directly connected to the RCA output jacks. Analog Devices recommends this 350Mhz op amp for use as a digital clock fan-out device.
It sounded good to start with except for some hiss like that heard on a radio station. I replaced the USB 5V power with a 2amp Belleson Vreg on my JLS interface board and the sound became magical except for continued light hissing. The bass is tight and deep. Voices sound natural. Percussion is precise. Music flows with a rich texture that is unfatiguing. And this is using JRiver in Windows 8 at 1XDSD dop from 44/16 source material so there is room for improvement.
About the hissing sound. Because a relay to switch between DSD signals being present or not seemed clunky to me I designed a JLS interface board to switch to a 3Mhz square wave derived from the Pin 20 12Mhz signal from the JLS board when there is no DSD signal. There is no hiss at all with this simulated DSD signal representing a 0 volt analog signal. I can see this square wave on a scope going into and out of the op amp, but with no hiss. When I switch to music I get hiss. Any ideas? Could it be the JLSounds board?
I am also having problems with occasional snapping sounds at 1XDSD but are very frequent at 2XDSD. I have version 2 of this interface board coming in shortly which might solve the snapping sounds.
Attachments
Nice work Ross! 🙂
1XDSD is DSD64 right? I think the consensus was that you needed higher res, preferably more like DSD256 4XDSD to get the best out of a solution like this and avoid additional noise?
1XDSD is DSD64 right? I think the consensus was that you needed higher res, preferably more like DSD256 4XDSD to get the best out of a solution like this and avoid additional noise?
Making Progress
I put one of the early versions of the SE Relay RC boards on the JLSounds and used output capacitors to get rid of the DC offset. There was no hissing which means that my JLSounds board is good and that JRiver was not generating the hiss. I still had the snapping sound but this went away when I changed the XMOS output from ASIO to WASAPI. Now 2xDSD has no snapping sounds. The hissing must be some interference from my DIY JLS interface board.
The sound quality was good but didn't have the musical detail and magic I heard before. I removed the capacitor of the RC filter and connected the DSD signals to my op amp board to remove the DC offset and use the op amp to drive the signal through an RC filter. The music now has more detail and is more listenable. Tomorrow I will replace the USB power with a 5V Belleson located right at the SE Relay RC board.
I put one of the early versions of the SE Relay RC boards on the JLSounds and used output capacitors to get rid of the DC offset. There was no hissing which means that my JLSounds board is good and that JRiver was not generating the hiss. I still had the snapping sound but this went away when I changed the XMOS output from ASIO to WASAPI. Now 2xDSD has no snapping sounds. The hissing must be some interference from my DIY JLS interface board.
The sound quality was good but didn't have the musical detail and magic I heard before. I removed the capacitor of the RC filter and connected the DSD signals to my op amp board to remove the DC offset and use the op amp to drive the signal through an RC filter. The music now has more detail and is more listenable. Tomorrow I will replace the USB power with a 5V Belleson located right at the SE Relay RC board.
More Changes Needed with JLS Relay board
Tonight I put a 5 Volt Belleson Vreg right at the input to the JLS USB external power terminal block. The sound became hyper-detailed. Instrument and voice separation was as pronounced as I have ever heard, but the sound is on the cold and unemotional side. The music didn't flow.
So far I haven't equaled the SQ from using a JLS interface of my own design, but was accompanied with too much hiss. I am trying to achieve the best sound possible using the SE Relay RC board before continuing to improve my interface board design.
Next I am going to put a Potato Semi buffer IC at the input to the DC blocking cap on my op amp board to provide DSD data streams that are as square and free of ringing as possible.
Tonight I put a 5 Volt Belleson Vreg right at the input to the JLS USB external power terminal block. The sound became hyper-detailed. Instrument and voice separation was as pronounced as I have ever heard, but the sound is on the cold and unemotional side. The music didn't flow.
So far I haven't equaled the SQ from using a JLS interface of my own design, but was accompanied with too much hiss. I am trying to achieve the best sound possible using the SE Relay RC board before continuing to improve my interface board design.
Next I am going to put a Potato Semi buffer IC at the input to the DC blocking cap on my op amp board to provide DSD data streams that are as square and free of ringing as possible.
Hi,
I'm using the SE board too, just used a pair of 2,2uF/205V MCaps on the output w/o the res, feeding a DCB1. No hiss or "strange noises" at all. I'm powering it with a Reflektor-D on the clean side, LT3080 on the dirty side.
Hope it helps!
Not there yet
ghiglie,
Sounds like you have taken the SE board about as far as it can go. I enjoy experimenting with audio circuits and seldom take the easy path. What RC components do you use?
Today I built a Potato Semi buffer and inserted it into the signal path from the SE relay board to the digital DC blocking cap of the op amp. The music flows much better, but is not quite right. There is also more hiss than I want.
The SE Relay board has the resistors of the RC filters right at the JLS DSD pins. It appears that any extra wire or PCB trace from the DSD pins acts as an antenna that adds noise to the signal.
I received the next version of my DIY JLS interface board which I hope to test this weekend.
ghiglie,
Sounds like you have taken the SE board about as far as it can go. I enjoy experimenting with audio circuits and seldom take the easy path. What RC components do you use?
Today I built a Potato Semi buffer and inserted it into the signal path from the SE relay board to the digital DC blocking cap of the op amp. The music flows much better, but is not quite right. There is also more hiss than I want.
The SE Relay board has the resistors of the RC filters right at the JLS DSD pins. It appears that any extra wire or PCB trace from the DSD pins acts as an antenna that adds noise to the signal.
I received the next version of my DIY JLS interface board which I hope to test this weekend.
Keeping those tracks as short as possible to avoid the situation you describe was something that our 'digital PCB layout' experts fed into the iterative refinement process when I did the group buy. That's why I laid out the board for physically small resistors and caps too.
Ray
I have noticed that more complicated filters than RC, or multiple RC in series, mess with the current output phase. But a for example 3Kohm/1nF RC filter leaves a lot of noise in the signal even with DSD256. Current phase is OK. I have attached a picture of the transient run with DSD256. PM me for the test tone; it is too big.
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Could you post a picture of measuring with 1K 3.3nF?
Good to know you have a test tone😀.
It's a DSD file converted to something like a 1-bit wav. I needed it like that because TINA-TI only opens WAVs
Why do you used a DSD file to convert 1-bit Wav?
What converter did you used?
Why don't used a PCM file for Wav?
What converter did you used?
Why don't used a PCM file for Wav?
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I had a 384kHz test tone as input, so I converted it to DSD256 then back to WAV at the same frequency. I wasn't sure how to directly convert it. If it makes a difference I can try to convert it directly.
I used SoX with additions by mansr... search sox mansr to find it
I didn't use PCM because I need to simulate what is at the output of the NoDAC, which is1 bit (DSD). Is that what you meant with your question?
I didn't use PCM because I need to simulate what is at the output of the NoDAC, which is1 bit (DSD). Is that what you meant with your question?