ProtoDAC TDA1387 X8 project

[Tim Curtis]

I have been comparing the stock ProtoDac i2s from the MoOde drop-down (with polarity inversion and Fixed-volume out) with the ProtoDac V2 setting from the CamillaDSP tab and prefer the former.

Mark, I note you use a Pi Zero W as your source and have seen on another forum you prefer it for lower CPU-activity hash.
I seem to recall the Zero W (not 2) is not 64bit so presumably is legacy and also not capable of running CamillaDSP so you're using the MoOde-rpi i2s setting?

I have added a Kali to the stack and at this early stage feel it detracts by losing air and dynamics and muddying vocals.
This may be that my Kali has the higher clocks and outputs to 384kHz ....and is not as suited to the ProtoDac as the version that topped out at 192kHz ?

Phase shift being better for the latter ?

I still have a LPS to try for the Kali...in other stacks I found the Pi was better supplied with it's own RPI wall-wart and isolated from the LPS supply to the Kali so will try both powering the full stack from the LPS and powering only the Kali and ProtoDac from the LPS and the Pi from an RPI supply.

cheers,
Bob

Try using native source sample rate and avoid any resampling before outputting to ProtoDAC.

I've seen the term "cpu hash" or similar pop up on various audio forums. The term has negative connotations because of what it implies but I've never seen proof that any particular level of CPU activity affects the audio signal.

If there's proof then maybe post a new Thread for discussion.

[hifinet]

I have been comparing the stock ProtoDac i2s from the MoOde drop-down (with polarity inversion and Fixed-volume out) with the ProtoDac V2 setting from the CamillaDSP tab and prefer the former.

Mark, I note you use a Pi Zero W as your source and have seen on another forum you prefer it for lower CPU-activity hash.
I seem to recall the Zero W (not 2) is not 64bit so presumably is legacy and also not capable of running CamillaDSP so you're using the MoOde-rpi i2s setting?

I have added a Kali to the stack and at this early stage feel it detracts by losing air and dynamics and muddying vocals.
This may be that my Kali has the higher clocks and outputs to 384kHz ....and is not as suited to the ProtoDac as the version that topped out at 192kHz ?

Phase shift being better for the latter ?

I still have a LPS to try for the Kali...in other stacks I found the Pi was better supplied with it's own RPI wall-wart and isolated from the LPS supply to the Kali so will try both powering the full stack from the LPS and powering only the Kali and ProtoDac from the LPS and the Pi from an RPI supply.

cheers,
Bob

Yes, I am using polarity inversion under DSP options in Audio configuration with 0dB volume. No upsampling. I think the files sounds best at the original sample rate. My Kali is capable of 384kHz. In the past, I have used the trial version of PGGB and made high quality upsampled files to 384kHz with 115 million taps, and did not have a preference compared to the original file. Yes, you can hear the higher sample rate "air" in the noise with the 384kHz file, but the music sounds the same to me.

[bobdcarr]

Wow, I must say, for the price of a Pi3B+ and a ProtoDAC, this is definitely the best value out there.

I ran a comparison between the ProtoDAC (with linear Power Supply) and my current setup, Allo DigiOne --> SPDIF --> Arcam iRDAC (with linear Power Supplies).

I am in no way saying the protoDAC is not awesome, but I did hear some discrepancies between the 2 systems (I've probably tried a dozen other systems before choosing on the Allo / Arcam solution). Here is my opinion of the ProtoDAC in comparison:
- Low end  not as focused
- less bite / punch (not as impactful)
- slightly less sparkle
- less wide of a soundstage

Very subtle differences but noticeable. 

Here are my questions:
- will the reclockers (Kali / Fifo) fix any of this?
- Will moving the power supply to the ProtoDAC PCB, instead of USBmicro have any affect?

FYI, I am using this as one of my reference tracks (if you click, it will download the wav file):
https://archive.org/download/sts-test-de...0theme.wav
or entire cd here (will not download wav, just the web page):
https://archive.org/details/sts-test-dem...-vol.i-wav

Thanks to everyone involved in this entire project (I have been a Moodie for a couple years now).

[hifinet]

Wow, I must say, for the price of a Pi3B+ and a ProtoDAC, this is definitely the best value out there.

I ran a comparison between the ProtoDAC (with linear Power Supply) and my current setup, Allo DigiOne --> SPDIF --> Arcam iRDAC (with linear Power Supplies).

I am in no way saying the protoDAC is not awesome, but I did hear some discrepancies between the 2 systems (I've probably tried a dozen other systems before choosing on the Allo / Arcam solution). Here is my opinion of the ProtoDAC in comparison:
- Low end  not as focused
- less bite / punch (not as impactful)
- slightly less sparkle
- less wide of a soundstage

Very subtle differences but noticeable. 

Here are my questions:
- will the reclockers (Kali / Fifo) fix any of this?
- Will moving the power supply to the ProtoDAC PCB, instead of USBmicro have any affect?

FYI, I am using this as one of my reference tracks (if you click, it will download the wav file):
https://archive.org/download/sts-test-de...0theme.wav
or entire cd here (will not download wav, just the web page):
https://archive.org/details/sts-test-dem...-vol.i-wav

Thanks to everyone involved in this entire project (I have been a Moodie for a couple years now).

You currently have the teaser setup. A little taste of what is possible. Reclockers and isolators will help significantly. The power supply can affect soundstage and bass. The C3/C4 Panasonic caps take about 60 hours to break in. The ultracap and LifePO4 power supplies have very good low bass punch. Also, more transparent output coupling caps, such as the Jantzen Superior Z-cap (large, but 3.3uF fits the PCB better) mentioned by @Ludomaniac in post #427.

Don't forget to set polarity inversion to ON in Audio configuration, DSP options.

[hifinet]

Rather than a reclocker/isolator, you could just add a DIR9001 SPDIF to I2S board. Then use your Allo DigiOne to feed it SPDIF.  The DigiOne already has isolation and low jitter.

GPIO pin 12 = BCK, pin 35 = LRCK, pin 40 = DATA

Connections

[bobdcarr]

Wow, I must say, for the price of a Pi3B+ and a ProtoDAC, this is definitely the best value out there.

I ran a comparison between the ProtoDAC (with linear Power Supply) and my current setup, Allo DigiOne --> SPDIF --> Arcam iRDAC (with linear Power Supplies).

I am in no way saying the protoDAC is not awesome, but I did hear some discrepancies between the 2 systems (I've probably tried a dozen other systems before choosing on the Allo / Arcam solution). Here is my opinion of the ProtoDAC in comparison:
- Low end  not as focused
- less bite / punch (not as impactful)
- slightly less sparkle
- less wide of a soundstage

Very subtle differences but noticeable. 

Here are my questions:
- will the reclockers (Kali / Fifo) fix any of this?
- Will moving the power supply to the ProtoDAC PCB, instead of USBmicro have any affect?

FYI, I am using this as one of my reference tracks (if you click, it will download the wav file):
https://archive.org/download/sts-test-de...0theme.wav
or entire cd here (will not download wav, just the web page):
https://archive.org/details/sts-test-dem...-vol.i-wav

Thanks to everyone involved in this entire project (I have been a Moodie for a couple years now).

You currently have the teaser setup. A little taste of what is possible. Reclockers and isolators will help significantly. The power supply can affect soundstage and bass. The C3/C4 Panasonic caps take about 60 hours to break in. The ultracap and LifePO4 power supplies have very good low bass punch. Also, more transparent output coupling caps, such as the Jantzen Superior Z-cap (large, but 3.3uF fits the PCB better) mentioned by @Ludomaniac in post #427.

Don't forget to set polarity inversion to ON in Audio configuration, DSP options.

Thanks, the polarity reversal helped, it's pretty close in sound now to my original system, the previous commetns stand but even less subtly, lol.
I was going to ask about burn in. Been playing for 24 hours now, I'll give it another comparison next week. I am going to try to isolate the 5V supplies and supply the DAC PCB with LifePO batts. Might have to try those caps as well.

[bobdcarr]

Rather than a reclocker/isolator, you could just add a DIR9001 SPDIF to I2S board. Then use your Allo DigiOne to feed it SPDIF.  The DigiOne already has isolation and low jitter.

GPIO pin 12 = BCK, pin 35 = LRCK, pin 40 = DATA

Connections

Thanks, being a master tweaker, I will now have to try what you suggested since the SPDIF to I2S board is so inexpensive. I am currently running 2 Allo Digione Pi's so I can afford to experiment with one. I plan on building an enclosure with all of the components.

As far as LifePO, I wonder if anyone has tried using a USB Lithium Power Bank so I can leave it in the enclosure, just charge it from the 5V linear that will power the Pi and run the output to the ProtoDAC PCB.

Cheers!

[hifinet]

Rather than a reclocker/isolator, you could just add a DIR9001 SPDIF to I2S board. Then use your Allo DigiOne to feed it SPDIF.  The DigiOne already has isolation and low jitter.

GPIO pin 12 = BCK, pin 35 = LRCK, pin 40 = DATA

Connections

Thanks, being a master tweaker, I will now have to try what you suggested since the SPDIF to I2S board is so inexpensive. I am currently running 2 Allo Digione Pi's so I can afford to experiment with one. I plan on building an enclosure with all of the components.

As far as LifePO, I wonder if anyone has tried using a USB Lithium Power Bank so I can leave it in the enclosure, just charge it from the 5V linear that will power the Pi and run the output to the ProtoDAC PCB.

Cheers!

The lithium battery power banks have a DC-DC converter, so they are noisy, but OK to power the RPi especially if you have isolation to ProtoDAC.

The other nice thing about the DIR9001 setup is that it and ProtoDAC can be in their own enclosure, and with the coax cable provide some distance away from the noisy RPi.

[bobdcarr]

Rather than a reclocker/isolator, you could just add a DIR9001 SPDIF to I2S board. Then use your Allo DigiOne to feed it SPDIF.  The DigiOne already has isolation and low jitter.

GPIO pin 12 = BCK, pin 35 = LRCK, pin 40 = DATA

Connections

Thanks, being a master tweaker, I will now have to try what you suggested since the SPDIF to I2S board is so inexpensive. I am currently running 2 Allo Digione Pi's so I can afford to experiment with one. I plan on building an enclosure with all of the components.

As far as LifePO, I wonder if anyone has tried using a USB Lithium Power Bank so I can leave it in the enclosure, just charge it from the 5V linear that will power the Pi and run the output to the ProtoDAC PCB.

Cheers!

The lithium battery power banks have a DC-DC converter, so they are noisy, but OK to power the RPi especially if you have isolation to ProtoDAC.

The other nice thing about the DIR9001 setup is that it and ProtoDAC can be in their own enclosure, and with the coax cable provide some distance away from the noisy RPi.

I have 7.4V battery packs and was going to regulate down to 5V, but can the ProtoDAC board handle the 7.4 (which can go to 8.6V)?


Another consideration is, how do people deal with charging LifePO? Was wondering the same for Allo Signature. 

I did notice the Digione cleaned up the bass, compared to my previous Hifiberry DigiPro+

[hifinet]

ProtoDAC can only handle 5V (5.5V max). You can use an LT1963 module to regulate down to 5V. The one problem with the LiPO is the higher ESR (internal resistance) compared to LifePO4 batteries. The LiPO don't sound as dynamic.

The Soviet K77-1 polycarbonate caps sound excellent. Just trying them now. Great value. Sound better than the used CRC 10uF 30V.

I use the LiitoKala Lii-202 .