Hi Bill,
I think it was this that set me off:
"For a person usually being very careful for what you say, what you mention here holds no ground at all."
Other people could be criticized in for saying things similar to my original point. Of course, everyone thinks their own reasoning is justified while its the other guy who clearly has it wrong. I'm sure some of the experts over at ASR would quite confidently tell us we both have it wrong. And they would be sure they are right.
I think it was this that set me off:
"For a person usually being very careful for what you say, what you mention here holds no ground at all."
Other people could be criticized in for saying things similar to my original point. Of course, everyone thinks their own reasoning is justified while its the other guy who clearly has it wrong. I'm sure some of the experts over at ASR would quite confidently tell us we both have it wrong. And they would be sure they are right.
Mark,
You are seemingly assuming that I don’t believe in a separate 5Volt Amanero’s supply. For measuring it makes no difference but for auditioning things are different.
My USB to SP/DIFF converter also has a separate 5 Volt supply, much to my satisfaction as an improvement.
We both know that that not everything that counts in audio perception can be measured and vice versa.
And please stop being insulted when there is no intention to and playing the guy who knows it all but wants to keep it for himself.
There are many people knowing much more than we do.
I fully respect your opinion, but when you are suspect of derailing you can expect critical comments, fair enough.
Hans
Simple power supply change:
Each rail is on its own transformer winding. Only common ground connection is at the dac.
Sound is getting deeper, with more space and detail. At the same time certain remaining distortion is more obvious. Compared balanced and SE again. SE sounds more distorted yet better space and detail. OTOH balanced is less distorted but it really hurts the space and detail. So, just have to go after the distortion.
Probably time to add galvanic isolation of the USB ground and the better clocking of I2SoverUSB.
Each rail is on its own transformer winding. Only common ground connection is at the dac.
Sound is getting deeper, with more space and detail. At the same time certain remaining distortion is more obvious. Compared balanced and SE again. SE sounds more distorted yet better space and detail. OTOH balanced is less distorted but it really hurts the space and detail. So, just have to go after the distortion.
Probably time to add galvanic isolation of the USB ground and the better clocking of I2SoverUSB.
Mark,
For what I experienced, the Amanero Wasapi can be used for DSD64 and DSD128 and only the Amanero Asio driver can be used up to DSD512.
Hans
Mark,
When measuring the RTZ Firdac, I used a battery powered Preamp and a laptop, so everything behind the Dac was floating.
The soon I connected the laptop to it's charger, I got lots of rubbish added to the signal.
As I understand you are using a headphone amp, is this amp battery powered or connected to mains, if possible a battery connection could improve things quite a bit.
Another suggestion could be to use a 5 Volt USB Power pack to feed the Amanero, thereby also removing a possible source of disruption by capacitive coupling to mains and or ground loops to the other supplies.
Hans
Yeah. Something doesn't make sense here. Will put off troubleshooting for now though.
Turns out the adapter board I have for Simple DSD Converter works to interface I2SoverUSB to Marcel's dac:
I2SoverUSB clocks are still warming up, but the distortion nearly all gone. Maybe 95% gone. Using two isolated 5v supplies for I2SoverUSB, one for the dac side and the other for the USB side. There is also a 3.3v power input for an inverter for the DSD_ON signal on the adapter board, as can be seen in the lower right hand corner of the pic. Normally the inverter would be powered by the Simple DSD Converter board.
I2SoverUSB clocks are still warming up, but the distortion nearly all gone. Maybe 95% gone. Using two isolated 5v supplies for I2SoverUSB, one for the dac side and the other for the USB side. There is also a 3.3v power input for an inverter for the DSD_ON signal on the adapter board, as can be seen in the lower right hand corner of the pic. Normally the inverter would be powered by the Simple DSD Converter board.
Mind the power sequencing requirements of post #88:
At start-up, the -15 V supply has to reach -0.3 V no later than 180 milliseconds after the +15 V exceeds +5 V. This is related to the common-mode input voltage range of U1A. You could get a too high voltage at U1A's output when you run it without negative supply, as long as that happens no longer than 180 ms, the voltage at C8 will not overshoot 5 V and no harm will be done. This requirement will easily be met by any normal dual power supply.
For the same reason, at power down, the -15 V should not become less negative than -0.3 V until the +15 V has dropped below 5 V. This will also easily be met, if only because the current drawn from the +15 V is much greater than the current from the -15 V.
At start-up, the -15 V supply has to reach -0.3 V no later than 180 milliseconds after the +15 V exceeds +5 V. This is related to the common-mode input voltage range of U1A. You could get a too high voltage at U1A's output when you run it without negative supply, as long as that happens no longer than 180 ms, the voltage at C8 will not overshoot 5 V and no harm will be done. This requirement will easily be met by any normal dual power supply.
For the same reason, at power down, the -15 V should not become less negative than -0.3 V until the +15 V has dropped below 5 V. This will also easily be met, if only because the current drawn from the +15 V is much greater than the current from the -15 V.
Latest audible improvment:
Some shielding. Getting close to time to hook it up to the main system.
Impression at this time is that I am listening to a string of op amps, and clocking could be better. There are options though. One thing at a time. Feel like its still too soon for a fair comparison with Andrea's dac.
Some shielding. Getting close to time to hook it up to the main system.
Impression at this time is that I am listening to a string of op amps, and clocking could be better. There are options though. One thing at a time. Feel like its still too soon for a fair comparison with Andrea's dac.
Even though measurements have a really bad rap in this thread I'll go against the tide and present some measurements of RTZ dac.
Note that these measurements are not from Marcel's original boards but my rendering of the same dac. Here is a picture of the dac.
It is a single board version (sans the last filter stage). Schematic is the same as original with only small modifications in the mute relay circuit as I used 5V relays. Parts are mostly same but I used smaller IC packages and MELFs in analog circuits. Main reasons for making my own version are the form factor and the connection to the USB-I2S as I wanted to use my own STM32F723 board. I use MMCX for I2S/DSD signals.
Here is another picture of the RTZ dac next to my ES9038Q2M dual dac. Both use same form factor for input and output connectors which makes it easier to swap dacs in chassis.
Here is a picture of the measurement setup. ADC is AK5394. DAC and ADC are powered from my SilentSwitcher which in turn is powered from a power bank. My USB-I2S board uses USB power. It can be powered from a 5V battery but I have not found any reason to do that neither in listening nor in measurements. Please note the high-end audiophile power bank from Lidl
.
Ok. Then the measurements. I used Multitone Analyzer as it has built in DSD measurement signals. Measurements were made with DoP64.
First 1kHz sine.
Very good. Distortion is low and high order HD is missing. Noisefloor could be better. More on that later.
Just for comparison here is the same measurement with my ES9038Q2M DAC.
It is worth mentioning that with DSD input ES9038Q2M THD is much cleaner than with PCM as all the high order harmonics are below the noisefloor. But noise is a bit higher than with PCM input.
Ok, back to RTZ.
Here is 60Hz sine:
As with 1kHz high order HD is below the noisefloor.
CCIF 19k/20k:
Very good.
Let's get back to the noise performance.
Here is SNR (i.e. DAC playing silence):
So SNR(A) is -97.5dB. I'm not sure if this can be directly compared to Hans' measurements as I have typically seen slightly worse noise numbers with Multitone Analyzer.
Finally let's delve into the Vref circuit as that is one of the exceptional features of Marcel's DAC.
Here is noise measurement of Vref circuit without any DSD signal. For noise measurements I used my 60dB LNA (Scott Wurcer's circuit).
Bandwidth in this measurement is 10Hz-20kHz. RMS noise (313 nV) is ultra low but a slight disappointment as that is more or less the same as I normally get with LT3042/45/94. Just as an example here is a noise measurement of the 15V that was used to power the Vref circuit in the previous measurement. This uses LT3045.
Since Marcel's Vref is much more complicated and uses lots of PCB real estate I don't really see it as in improvement over LT3042.
Regarding noise one thing I noticed while testing the board is that signals in digital section have quite high overshoots. Maybe it would be better to have series termination resistors in every signal connecting the logic ICs. That should at least mitigate against ground bounce.
How does it sound?
I'll get back to that later after Markw4 has finished with his not so hidden agenda.
Note that these measurements are not from Marcel's original boards but my rendering of the same dac. Here is a picture of the dac.
It is a single board version (sans the last filter stage). Schematic is the same as original with only small modifications in the mute relay circuit as I used 5V relays. Parts are mostly same but I used smaller IC packages and MELFs in analog circuits. Main reasons for making my own version are the form factor and the connection to the USB-I2S as I wanted to use my own STM32F723 board. I use MMCX for I2S/DSD signals.
Here is another picture of the RTZ dac next to my ES9038Q2M dual dac. Both use same form factor for input and output connectors which makes it easier to swap dacs in chassis.
Here is a picture of the measurement setup. ADC is AK5394. DAC and ADC are powered from my SilentSwitcher which in turn is powered from a power bank. My USB-I2S board uses USB power. It can be powered from a 5V battery but I have not found any reason to do that neither in listening nor in measurements. Please note the high-end audiophile power bank from Lidl
.Ok. Then the measurements. I used Multitone Analyzer as it has built in DSD measurement signals. Measurements were made with DoP64.
First 1kHz sine.
Very good. Distortion is low and high order HD is missing. Noisefloor could be better. More on that later.
Just for comparison here is the same measurement with my ES9038Q2M DAC.
It is worth mentioning that with DSD input ES9038Q2M THD is much cleaner than with PCM as all the high order harmonics are below the noisefloor. But noise is a bit higher than with PCM input.
Ok, back to RTZ.
Here is 60Hz sine:
As with 1kHz high order HD is below the noisefloor.
CCIF 19k/20k:
Very good.
Let's get back to the noise performance.
Here is SNR (i.e. DAC playing silence):
So SNR(A) is -97.5dB. I'm not sure if this can be directly compared to Hans' measurements as I have typically seen slightly worse noise numbers with Multitone Analyzer.
Finally let's delve into the Vref circuit as that is one of the exceptional features of Marcel's DAC.
Here is noise measurement of Vref circuit without any DSD signal. For noise measurements I used my 60dB LNA (Scott Wurcer's circuit).
Bandwidth in this measurement is 10Hz-20kHz. RMS noise (313 nV) is ultra low but a slight disappointment as that is more or less the same as I normally get with LT3042/45/94. Just as an example here is a noise measurement of the 15V that was used to power the Vref circuit in the previous measurement. This uses LT3045.
Since Marcel's Vref is much more complicated and uses lots of PCB real estate I don't really see it as in improvement over LT3042.
Regarding noise one thing I noticed while testing the board is that signals in digital section have quite high overshoots. Maybe it would be better to have series termination resistors in every signal connecting the logic ICs. That should at least mitigate against ground bounce.
How does it sound?
I'll get back to that later after Markw4 has finished with his not so hidden agenda.
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Very nice project @bohrok2610.
I fear this thread is becoming more about Markw4 than Marcel's RTZ DAC and I think I know how the story ends.
I fear this thread is becoming more about Markw4 than Marcel's RTZ DAC and I think I know how the story ends.
Its Acko's dac. If he wants his dac back right now all he has to do is say so. Might get interesting next week though. I have some parts coming that might help set a more fair basis for comparison.
Also, if Marcel wants to call it quits I am willing to go along with that as well.
The reality at the moment is that over a long period of time Andrea has produced a very high tech, and very expensive dac which can sound very good indeed.
OTOH Marcel has designed two boards that potentially could make the basis for a very good dac system. It looks something more like what Marantz is doing inside of some of their high-end products, except they use discrete op amps.
Anyway, we don't know much yet about the potential for Marcel's dac in terms of subjective SQ, I don't anyway. There is too much peripheral stuff still in the way at the moment. I am thinking about a way to help take some of those things out of the equation and get more to the crux of the basic sound. A fundamental question we have here is whether longer or shorter FIRDACs can potentially sound better, and or what kind components may sound better. Marcel's dac may help with that understanding, we hope so anyway.
Also, I would not say Andrea's dac is completely perfect. The output stage issue still needs more development. Its not an easy problem to solve well. Easy to do with op amps of course, if that's the sound you like.
Bottom line will probably be great vinyl can still sound smoother and more listenable than either dac, but vinyl reproduction at that level costs way more than either of these dacs. Was that the ending/agenda you were expecting?
Also, if Marcel wants to call it quits I am willing to go along with that as well.
The reality at the moment is that over a long period of time Andrea has produced a very high tech, and very expensive dac which can sound very good indeed.
OTOH Marcel has designed two boards that potentially could make the basis for a very good dac system. It looks something more like what Marantz is doing inside of some of their high-end products, except they use discrete op amps.
Anyway, we don't know much yet about the potential for Marcel's dac in terms of subjective SQ, I don't anyway. There is too much peripheral stuff still in the way at the moment. I am thinking about a way to help take some of those things out of the equation and get more to the crux of the basic sound. A fundamental question we have here is whether longer or shorter FIRDACs can potentially sound better, and or what kind components may sound better. Marcel's dac may help with that understanding, we hope so anyway.
Also, I would not say Andrea's dac is completely perfect. The output stage issue still needs more development. Its not an easy problem to solve well. Easy to do with op amps of course, if that's the sound you like.
Bottom line will probably be great vinyl can still sound smoother and more listenable than either dac, but vinyl reproduction at that level costs way more than either of these dacs. Was that the ending/agenda you were expecting?
@bohrok2610 : Thanks for sharing your measurements.
I notice you say that all measurements were at DoP64. Any chance you made some measurements at DSD128 or higher? Could be interesting to see if the RTZ DAC performs equally well at different sample rates (to my memory Hans Polak in his review did not mention which sample rate(s) his measurements were made at ..?) ...
Cheers, Jesper
I notice you say that all measurements were at DoP64. Any chance you made some measurements at DSD128 or higher? Could be interesting to see if the RTZ DAC performs equally well at different sample rates (to my memory Hans Polak in his review did not mention which sample rate(s) his measurements were made at ..?) ...
Cheers, Jesper
All the rates are mentioned in my review exept DSD64, which had a too large dynamic range for my test equipment, but S/N must be at least as good or even better as DSD128.
https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7403333
Contrary go the feeling that some might have, a S/N of 105dB(A)can only be regarded as excellent and so were the THD and IMD figures.
The negative discussion concerned the Amanero board at DSD512, but thx to Marco I’m not the only one with the negative experience.
Hand
https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7403333
Contrary go the feeling that some might have, a S/N of 105dB(A)can only be regarded as excellent and so were the THD and IMD figures.
The negative discussion concerned the Amanero board at DSD512, but thx to Marco I’m not the only one with the negative experience.
Hand
Overview of the measured noise floors:
-97.5 dB(A) for DSD64, bohrok2610, different board design, DAC + DIY STM32F723 board
-105.3 dB(A) for DSD128, Hans Polak, DAC + Amanero
-103.3 dB(A) for DSD256, Hans Polak, DAC + Amanero
-95.7 dB(A) for DSD512, Hans Polak, DAC + Amanero
-100.8 dB(A) for DSD512 with my PWM8 algorithm, Hans Polak, DAC + Amanero
-104.6 dB(A) at 27 Mbit/s PWM8, MarcelvdG, DAC + FPGA board and some other logic from an earlier DAC
-97.5 dB(A) for DSD64, bohrok2610, different board design, DAC + DIY STM32F723 board
-105.3 dB(A) for DSD128, Hans Polak, DAC + Amanero
-103.3 dB(A) for DSD256, Hans Polak, DAC + Amanero
-95.7 dB(A) for DSD512, Hans Polak, DAC + Amanero
-100.8 dB(A) for DSD512 with my PWM8 algorithm, Hans Polak, DAC + Amanero
-104.6 dB(A) at 27 Mbit/s PWM8, MarcelvdG, DAC + FPGA board and some other logic from an earlier DAC
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