Hi 
My first post.
I have a peachtree dac.it, and an Mhdt USBridge which has I2S out.
BACKGROUND
I have upgraded the caps in the dac.it and made a custom usb cable with a separate power supply with fabulous results. But I am still unhappy with the USB input of the dac.it compared with spidf in from my blu ray player. The dac.it uses adaptive sync and reclocks the signal.
QUESTION
I would like to connect the I2S out from the USBridge, but could not find any posts with sufficient info on how to modify an existing dac to receive I2S.
For example,
- Is it simply a matter of soldering the MCLK, LRCK, and word select from the I2S output onto the corresponding ES9022 pins?
- Would I need to disconnect either the signal or components already going to the ES9022 pins while receiving I2S?
If anyone could point me in the right direction that would be appreciated.
Thank you! Rob
My first post. I have a peachtree dac.it, and an Mhdt USBridge which has I2S out.
BACKGROUND
I have upgraded the caps in the dac.it and made a custom usb cable with a separate power supply with fabulous results. But I am still unhappy with the USB input of the dac.it compared with spidf in from my blu ray player. The dac.it uses adaptive sync and reclocks the signal.
QUESTION
I would like to connect the I2S out from the USBridge, but could not find any posts with sufficient info on how to modify an existing dac to receive I2S.
For example,
- Is it simply a matter of soldering the MCLK, LRCK, and word select from the I2S output onto the corresponding ES9022 pins?
- Would I need to disconnect either the signal or components already going to the ES9022 pins while receiving I2S?
If anyone could point me in the right direction that would be appreciated.
Thank you! Rob
Some I2S bords exist with this chip. One problem you have is to find also a gnd connection nears the pins. The best theoric situation is each signal needs its own return path line very close (like coaxial where the suround is the gnd and shielding in relation to the others close I2S lines)...
But we see (too) many links betwwen USB boards and dac boards with I2S GSSSS pins arrengement only (G=gnd-return path; S=sigal) : which means all the return signals are travelling in just one Gnd wire too far of their rspective signal wire : those last signal wires too close of each others with bad interactions as there is no dedicated gnd wire between each Signal wire) : so jitter, etc... the highers fhz the more problems you will have. Of course also the two pcbs needs a good layout in relation to such needs... : impedance, return paths just near each S link or continous ground just below each signal path on the pcbs...
Note a i2s connection is 10 to 15 cm max, even in the best arrengement : GSGSGSGS.. (with uf.l wires & connectors which has matched impedance connectors)
My understanding with 50 Mhz which is a middle RF frequency : you really need a good interconnect !
But we see (too) many links betwwen USB boards and dac boards with I2S GSSSS pins arrengement only (G=gnd-return path; S=sigal) : which means all the return signals are travelling in just one Gnd wire too far of their rspective signal wire : those last signal wires too close of each others with bad interactions as there is no dedicated gnd wire between each Signal wire) : so jitter, etc... the highers fhz the more problems you will have. Of course also the two pcbs needs a good layout in relation to such needs... : impedance, return paths just near each S link or continous ground just below each signal path on the pcbs...
Note a i2s connection is 10 to 15 cm max, even in the best arrengement : GSGSGSGS.. (with uf.l wires & connectors which has matched impedance connectors)
My understanding with 50 Mhz which is a middle RF frequency : you really need a good interconnect !
Last edited:
I have had a play:
I took an rj45 terminated computer cable with 4 twisted pairs and chopped off one end to give a 120mm long cable.
Then soldered the signals directly to the es9022 pins, and the four earth wires near the es9022 ground pin at the same point (thanks Eldam for the comments about grounding and length).
I had no other signal coming into the dac except for the I2S.
All I heard was "digital noise" - some low level clicks and hiss.
I did not disconnect or turn the power off from the DACs te7022, nor any other connections to the es9022. Digital is new for me, and I do not know, for example, if I needed to turn off the clock on board the DAC ...
Was fun to try and the DAC still works, which is nice!
Could anyone point me to info on modifying existing DACs for I2S? I've googled and hunted this forum but haven't found a good place to start. It looks fairly straight forward for new builds, so I may have to venture there.
Thanks for you help
I took an rj45 terminated computer cable with 4 twisted pairs and chopped off one end to give a 120mm long cable.
Then soldered the signals directly to the es9022 pins, and the four earth wires near the es9022 ground pin at the same point (thanks Eldam for the comments about grounding and length).
I had no other signal coming into the dac except for the I2S.
All I heard was "digital noise" - some low level clicks and hiss.
I did not disconnect or turn the power off from the DACs te7022, nor any other connections to the es9022. Digital is new for me, and I do not know, for example, if I needed to turn off the clock on board the DAC ...
Was fun to try and the DAC still works, which is nice!
Could anyone point me to info on modifying existing DACs for I2S? I've googled and hunted this forum but haven't found a good place to start. It looks fairly straight forward for new builds, so I may have to venture there.
Thanks for you help
It works!
- I disconnected mclk - cheers didiet78
- I needed to power off the dac, usbridge, and restart jriver software between changing from spidf in to i2s in
- I needed to wait a few seconds (I don't know, about 5 seconds) before I could hear the i2s signal
Difference to the sound:
The usbridge (rev 1.3 using a CM6631) used in spidf mode added extra resolution and width compared to the usb on the dac.it (tenor te7022). Compared to the dac.it the vocals were slightly harsh and slightly sibilant, and noticeably less bass and warmth.
With I2S the graininess left, the sound stage was wider and noticeably deeper. My speakers for the first time disappeared from the sound stage. However, the bass and warmth was still noticeably less than the dac.it. But there was very little harshness; it was more like the treble was turned up / bass down (I have a fairly neutral system; the speakers have a slight low mid hump).
So while I adored the sound stage and resolution of the I2S, I can not live with it for enjoying music.
Out of interest, I notice the latest version of the usbridge uses a CM6631A.
Next step: I will look for a usb to I2S board that does not compromise the "bass / fullness", that I can add into the dac.it - any thoughts?
Thanks for you help!
- I disconnected mclk - cheers didiet78
- I needed to power off the dac, usbridge, and restart jriver software between changing from spidf in to i2s in
- I needed to wait a few seconds (I don't know, about 5 seconds) before I could hear the i2s signal
Difference to the sound:
The usbridge (rev 1.3 using a CM6631) used in spidf mode added extra resolution and width compared to the usb on the dac.it (tenor te7022). Compared to the dac.it the vocals were slightly harsh and slightly sibilant, and noticeably less bass and warmth.
With I2S the graininess left, the sound stage was wider and noticeably deeper. My speakers for the first time disappeared from the sound stage. However, the bass and warmth was still noticeably less than the dac.it. But there was very little harshness; it was more like the treble was turned up / bass down (I have a fairly neutral system; the speakers have a slight low mid hump).
So while I adored the sound stage and resolution of the I2S, I can not live with it for enjoying music.
Out of interest, I notice the latest version of the usbridge uses a CM6631A.
Next step: I will look for a usb to I2S board that does not compromise the "bass / fullness", that I can add into the dac.it - any thoughts?
Thanks for you help!
Changing the regulation made little difference to the fullness and bass.
This project has given me the technical and audio confidence to begin a new journey. Thanks!
I will get a DIYINHK ES9018K2M XMOS DSD DXD 384kHz USB DAC with Bit-perfect volume control and SPDIF input. But please tell me if you know of what may be better hardware implementation with which to begin my next journey!
This project has given me the technical and audio confidence to begin a new journey. Thanks!
I will get a DIYINHK ES9018K2M XMOS DSD DXD 384kHz USB DAC with Bit-perfect volume control and SPDIF input. But please tell me if you know of what may be better hardware implementation with which to begin my next journey!
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