Hello PDC Fans!
I'd like to very much reinforce Ulli's comment above! Giving the PDC really well designed DACs is a "budget" investment for a better sounding PDC device
I've taken the approach to connect the Soekris DAM1021 with 0.99 Firmware using SPDIF first and recently the AES Output of the DEQX DigOut Board my PDC happens to have installed. Result was a rather pleasing sound experience! More fine detail, (much) less harshness, simply put: "very nice".
The best thing: The mod to connect DAM1021 with SPDIF or AES Out is relatively simple! Here's a picture:
Having said that, there are a few things to keep in mind:
Winfried
I'd like to very much reinforce Ulli's comment above! Giving the PDC really well designed DACs is a "budget" investment for a better sounding PDC device
I've taken the approach to connect the Soekris DAM1021 with 0.99 Firmware using SPDIF first and recently the AES Output of the DEQX DigOut Board my PDC happens to have installed. Result was a rather pleasing sound experience! More fine detail, (much) less harshness, simply put: "very nice".
The best thing: The mod to connect DAM1021 with SPDIF or AES Out is relatively simple! Here's a picture:
Having said that, there are a few things to keep in mind:
- The Switch Mode Power Supply may have to go external or the DAC, the picture is therefore more a PoC.
- Considering
- Muting is an issue to be resolved with DAM1021, as it clicks loudly when DEQX PDC changes the sample rate synch or input.
- Using DAM1021 for all 3 ways will definitely necessitate an external DAC Housing (initial Tests suggest that I²S could still be used if no DigOut board available!
Winfried
2.way or 3-way output from DEQX 2.6p
I have a DEQX 2.6p that i wish to insert 3x DAM1021 or DAM1121 for 3-way output after the DSP so i can control time alignment, frequency and phase in the DEQX software, but bypassing its DACs(AD1853)
Have you figured out how to insert them for 2 or 3 way use?
Right now, i have inserted LC-Audio "ZapFilters" after each AD1853 DAC, these are just discreet design IV filters and to me, sounds very good, but i am not satisfied with the jitter in the oscillator in the DEQX.
So if i insert a new low jitter clock, i need to ensure the transporter is with the same clock, and to syncronize them, and i think the Soekris might be the solution instead, if only i could figure out where to take the signal out of the DEQX.
I have found the clock frequency in the DEQX to be 12.288MHz and found several who sell very low jitter clocks for this purpose but they all say i need to feed the transporter as well.
DEQX PDC 2.6P is nice.
Long time thought: using better dacs might even improve sound quality...
Well, this is the case.
I've just added 2 Soekris DAM1021 boards for channels 2 and 3, respectivelly.
An externally hosted image should be here but it was not working when we last tested it.
Here how the PoC currently looks like
Hugh improvement.
DAM1021 are connected to the PDC-2.6 main board the same way as the digital out board is connected: a ribbon cable carries a supply voltage and all i2s signals needed to feed DAM1021:
Some wires to connect the ribbon cable to the respective DAM1021 input - that's all needed
Soekris dam 1021 R-2R DAC ILLUSTRATED GUIDE | H i F i D U I N O will tell about the DAM1021 side.
The onboard buffer doesn't sound too well, as reported by friends I do trust. The r-2r raw output has 625 Ohm - a bit high in my case as my amps run with 3k at the input. My plan is to use SSB01 Sjöström Super Buffers directly behind r-2r raw output.
Feeding the DEQX with Arta generated 0dBFS gives just 200 mV at the r-2r raw out - to little for my gear.
DAM1021 is specified 1.4V at this output.
Closer look at the i2s signal reveals both, the reason and a possible solution:
Gain Adjust is set in my case not too many dBs below or above 0dB. In order to have +20dB head room, roughly the four MSB bits are off in this case (left side in the picture above). Gain Adjust set to +6dB gives another bit in the i2s signal (right side).
All fine so far - apart from not being able to use the Mute button anymore.
As DAM1021 muting is yet to be solved, the DEQX Mute will be on the list.
Happy ears
Ulli
I have a DEQX 2.6p that i wish to insert 3x DAM1021 or DAM1121 for 3-way output after the DSP so i can control time alignment, frequency and phase in the DEQX software, but bypassing its DACs(AD1853)
Have you figured out how to insert them for 2 or 3 way use?
Right now, i have inserted LC-Audio "ZapFilters" after each AD1853 DAC, these are just discreet design IV filters and to me, sounds very good, but i am not satisfied with the jitter in the oscillator in the DEQX.
So if i insert a new low jitter clock, i need to ensure the transporter is with the same clock, and to syncronize them, and i think the Soekris might be the solution instead, if only i could figure out where to take the signal out of the DEQX.
I have found the clock frequency in the DEQX to be 12.288MHz and found several who sell very low jitter clocks for this purpose but they all say i need to feed the transporter as well.
@memo
I do have very positive experience with a TentLab 12.288MHz clock being fed by a dedicated supply regulation circuitry incl. shunt regulation. The AD conversion is noticably cleaner and nicer this way
One important, maybe not widely known, note, though: The PDC-internal clock is not(!) used for the digital input data! Therefore the sound quality from digital inputs will not be affected by a new internal clock! The PDC-DACs basically use the clock decoded from the AES3 or SPDIF signal "as is". For this reason I am using an AES3/SPDIF reclocker to ffed the PDC with digital Signal. The PDC sound quality dependency on the dig signal quality coming from the source has been greatly reduced by this approach.
Greetings,
Winfried
I do have very positive experience with a TentLab 12.288MHz clock being fed by a dedicated supply regulation circuitry incl. shunt regulation. The AD conversion is noticably cleaner and nicer this way
One important, maybe not widely known, note, though: The PDC-internal clock is not(!) used for the digital input data! Therefore the sound quality from digital inputs will not be affected by a new internal clock! The PDC-DACs basically use the clock decoded from the AES3 or SPDIF signal "as is". For this reason I am using an AES3/SPDIF reclocker to ffed the PDC with digital Signal. The PDC sound quality dependency on the dig signal quality coming from the source has been greatly reduced by this approach.
Greetings,
Winfried
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