Paul, it's time for you to launch Subbu DAC V4.
Jean Paul, nice to meet you in this thread.
Both DACs are measured with Spdif out and analog input from RME AIO.
I used the stock Subbu DAC V3 and PSU soldered by Korben.
I was really suprised after I made the measurement.
The THD obtained stands well against DAC priced 10x ~ 100x higher.
The Subbu DAC V3 is a good example of careful engineering.
Well done!
However, the noise floor of Dam1021 is about 20db lower than that of Subbu DAC v3.
Paul, there is room for improvement. Maybe, it's time for you to launch Subbu DAC V4.
Thanks for including measurements of our V3 compared to a modified/improved DAM1021. I think the comparison is somewhat off as DAM1021 is way more expensive (and R2R) but still the Subbu V3 does perform quite good. To be honest I would choose the V3 if only measurements are concerned(just joking). Which PSU did you use on the V3 ? Were both DACs measured using SPDIF ?
Jean Paul, nice to meet you in this thread.
Both DACs are measured with Spdif out and analog input from RME AIO.
I used the stock Subbu DAC V3 and PSU soldered by Korben.
I was really suprised after I made the measurement.
The THD obtained stands well against DAC priced 10x ~ 100x higher.
The Subbu DAC V3 is a good example of careful engineering.
Well done!
However, the noise floor of Dam1021 is about 20db lower than that of Subbu DAC v3.
Paul, there is room for improvement. Maybe, it's time for you to launch Subbu DAC V4.
Hi Arthur, I have to remind us we're in a paid thread of a vendor but V3 is not a current device anymore and it was a Group Buy thing so I guess we're on the safe side with just a few posts.
Yes, the V3 took a lot of time. I made more revisions than I can remember but it paid off. Please consider that we used a 4$ chip with a charge pump inside. IMHO it won't be possible to get a much lower noise floor than we achieved with that chip and I have my doubts if that is the most important parameter with these low levels. Still lower = better when possible. I think owners of a V3 can be satisfied listeners. I just love this comment as it was my goal to develop an affordable (OK, cheap) device with outstanding characteristics:
I thought about a V4 with USB and SPDIF but when I think of all the work....
Good luck with improving the DAM1021, I hope all the wrinkles get ironed out as it seems a very nice concept.
Yes, the V3 took a lot of time. I made more revisions than I can remember but it paid off. Please consider that we used a 4$ chip with a charge pump inside. IMHO it won't be possible to get a much lower noise floor than we achieved with that chip and I have my doubts if that is the most important parameter with these low levels. Still lower = better when possible. I think owners of a V3 can be satisfied listeners. I just love this comment as it was my goal to develop an affordable (OK, cheap) device with outstanding characteristics:
I thought about a V4 with USB and SPDIF but when I think of all the work....
Good luck with improving the DAM1021, I hope all the wrinkles get ironed out as it seems a very nice concept.
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I have used a r-core trafo with 1mtr of Vdh mainserver Hybrid pow cable with excellent sonic result.
Thank you for the reminder.
The Dam1021 DAC worths every penny paid.
I am looking forwards to the new production batch.
kuribo,
I'm going down the same road, but I don't see any implementation struggles...
What source do you use?
In case of a PC/Mac, all that you need is a multichannel usb-to-i2s converter like USBstreamer, from which you can distribute i2s signals to all four boards.
Load appropriate filters for each channel and enjoy some music
Or - better - do the first stage of filtering in software. HQPlayer is particularly good for the task.
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You can't just send signal to all 8 channels and expect the clocks to synch, at least that is how I understand it. I have the exa21 usb to i2s 8 channel converter. The software must be updated to allow one board to function as the master and the others as slaves.
Thanks for the suggestion though. Hope I am wrong.
Thanks for the suggestion though. Hope I am wrong.
There have been some writings here and on moreDAMfilters about the load regulation (also called noise) on the vref buffers, where people are measuring the vref rail like it's the actual output....
Just for fun I measured the resistance on a random LVC595's VCC wire, it's no less than 0.3 ohm.... That mean that once the original peaks on the vref buffers are eliminated, there is really no need to get much lower than maybe 0.05 ohms impedance on the vref lines, it doesn't really matter if it's much lower as there will always be 0.3 ohm in series at each LVC595 output driver....
Just for fun I measured the resistance on a random LVC595's VCC wire, it's no less than 0.3 ohm.... That mean that once the original peaks on the vref buffers are eliminated, there is really no need to get much lower than maybe 0.05 ohms impedance on the vref lines, it doesn't really matter if it's much lower as there will always be 0.3 ohm in series at each LVC595 output driver....
That's fascinating. I wonder if you can describe the sound siganture of these different DAC's and share what you love about the dam1021 please?
Maybe THD measurements dont relate to listener pleasure when the noise is under -96dB as it might be inaudible as mentioned before?
That raises the question in my mind - are there any measurement parameters that can explain listener preferences?
Soekris, is there a section of DAM schematic that you can share to illustrate this?
multichannel config - clocks drifting?
Kuribo, have you actually tried that config? Slight deviation (less than 0.1 ms) will be inaudible.
Søren, how much may the clocks drift out of sync between several boards, worst case, assuming we send synchronized bitclock/data to each?
Kuribo, have you actually tried that config? Slight deviation (less than 0.1 ms) will be inaudible.
Søren, how much may the clocks drift out of sync between several boards, worst case, assuming we send synchronized bitclock/data to each?
From my own experience and my humble attempt to relate sound to technical performance between different dacs i'd say the following matters:
Microdynamic accuracy (precision). This is where ladder dacs have the upper hand i think.
Precision in time domain. Jitter performance is often better on ladder dacs as well.
Ladder/multibit dacs i have heard are only Yggdrasil and Dam (really damn impressive units), so it might be unfair to say all S-D dacs suck, just those i have heard do.
In my experience noise under -70dB is irrelevant compared to other things. Whether its amplifiers or sources.
THD should be taken apart to D2, D3, D4 vs freq etc to get meaningful information about a device.
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Multople dam1021's clocks will sync to less than one word clock period, probably to one bitclock, so the plan for multiple units is simply to parallel the inputs....
The trick is also to track commands, like input source select, filter select and volume, and that will be possible by connecting the isolated serial ports together.
Will be supported by next firmware release, which will be released before this weekend....
Hooray -
Good work. BTW: Think I got lost in "mods" and "measurements" the last couple of months.
Ugh, Kuribo, you wait several months just to hear this...
Let's start connecting the boards!
Glad to hear about the FW update.