I think I know the setup - a Guru and some Disciples. The Guru will lead any listening session to the desired goal. If one do not comply, one might not be welcome anymore. I too was a disciple long ago but managed to break out of it. It can be a bit scary as at times these constellations gets a bit "sectristic"...
I am convinced an AP would likely (hopefully?) provide an answer to the question what measurement parameters change when e.g. modifying the Amanero power supply. However, I expect more pointers will come from analyzing the digital signal, what no AP can do, and even more convinced that the parameters that do change and measured by an AP (analog), could very well be a secondary effect instead of direct effect of the change to the power supply.
Using an AP is nice for a snapshot, but if you want to get somewhere, you use it while developing the dac and in conjunction with listening sessions. Just sending it over would be meaningless.
Using an AP is nice for a snapshot, but if you want to get somewhere, you use it while developing the dac and in conjunction with listening sessions. Just sending it over would be meaningless.
Sorry, I have to disagree. The problem with Amanero is that it does not have any galvanic isolation either at USB or at I2S/DSD side. But the only way Amanero power supply could have impact in bit perfect asynchronous UAC is through noise which would somehow impact the generated DSD output signals. That noise would very likely show up in measurements as we have seen with my case.
Listening without measuring (as Markw4 would have it) can only lead to subjective and speculative improvements. I don't know anything about Markw4's listening capabilities but when it comes to subjective listening I'm 110% sure that I'm the best judge for what I like. Trust your own ears, not somebody else's ears.
I use Amanero with great satisfaction. (previously used JLSounds). Amanero provides the capability to work as slave, in DSD mode. It picks up the MCLK from my feed. (From a Mori oscillator, and transformer coupled/padded)
In my case the dac kit itself (4499eq) provides galvanic isolation on the input signals. MCLK (Mori) gets directly to the onboard clock buffer, DC coupled. (obviously it works from an independent floating DC supply, so no loops)
At a time back, DiyHK distributed galvanic isolator piggyback boards for Amanero, in case of a dac without isolators.
Shamefully I did not look it up right now, would it not be possible to try something similar here?
In my case the dac kit itself (4499eq) provides galvanic isolation on the input signals. MCLK (Mori) gets directly to the onboard clock buffer, DC coupled. (obviously it works from an independent floating DC supply, so no loops)
At a time back, DiyHK distributed galvanic isolator piggyback boards for Amanero, in case of a dac without isolators.
Shamefully I did not look it up right now, would it not be possible to try something similar here?
Quick report:
Group listening session didn't happen.
However, today a pro audio designer dropped by and listened to the dac as it is now. He said let's hear it in SE, he listened about half of a song, said, okay, now balanced. Listened a little longer, then, okay stop.
This is what he then said to me without any prior discussion between us: I like it. It has a lot of potential. It only needs a little more work. He said, I can hear what the opamps are doing, but that can be fixed with a little discrete circuitry.
I said, Yeah, I know. Then we talked about some other stuff and he left.
Of course, this guy is not going to give away anything for diy use. He is always thinking about making products for sale, since that's how he makes his living.
Group listening session didn't happen.
However, today a pro audio designer dropped by and listened to the dac as it is now. He said let's hear it in SE, he listened about half of a song, said, okay, now balanced. Listened a little longer, then, okay stop.
This is what he then said to me without any prior discussion between us: I like it. It has a lot of potential. It only needs a little more work. He said, I can hear what the opamps are doing, but that can be fixed with a little discrete circuitry.
I said, Yeah, I know. Then we talked about some other stuff and he left.
Of course, this guy is not going to give away anything for diy use. He is always thinking about making products for sale, since that's how he makes his living.
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With slave mode do you mean that MCK is input to Amanero? That is how my STM32F7 board works as well (and probably also I2SoverUSB).
Isn’t that what most of us including Mark are saying.
In this forum it can be interesting to read about someone elses experience no matter how they come to their conclusions, but in the end you should decide for yourself.
I don’t give a damn when I like something that nobody else does.
And I don’t need blind tests to be happy with what I have, even when it means that I’m fooling myself, who cares. 😛
Any of you guys are welcome to visit and listen on the system here. Might be surprised what can be heard. PM if any interest.
Nobody does. But if you plan to claim your setup is better than the rest you sure should do some blind tests first 😉
Yes, exactly.
As far as I had it from a closer look, some kind of reclocking would be needed after the isolators (clean side). That could be still implemented in such a piggy board solution..
Or, rather than a clock doubler an MCLK divider could be applied as You had done it..🤔 (if already an MCLK is available on the clean, dac side..)
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Usually Analog or Intersil isolators are used.
Analog:
THEORY OF OPERATION analog.com Rev. A | 20 of 25 The ADuM340E/ADuM341E/ADuM342E use a high frequency carrier to transmit data across the isolation barrier via iCoupler chip scale transformer coils separated by layers of polyimide isolation.
https://www.analog.com/media/en/technical-documentation/data-sheets/adum340e-341e-342e.pdf
Intersil (now Renesas)
GMR Isolators' EMC advantages can be traced to their revolutionary spintronic GMR technology. The input drives a low-field generator. The field changes the electron spin polarization, which changes the resistance of the Giant Magneto-Resistor (GMR) bridge elements. Unlike transformers or conventional coils, this does not rely on energy transfer, so EMI emissions are minimal.
https://www.renesas.com/us/en/document/dst/isl71710slhm-datasheet?r=1518186
Seems magnetic
Analog:
THEORY OF OPERATION analog.com Rev. A | 20 of 25 The ADuM340E/ADuM341E/ADuM342E use a high frequency carrier to transmit data across the isolation barrier via iCoupler chip scale transformer coils separated by layers of polyimide isolation.
https://www.analog.com/media/en/technical-documentation/data-sheets/adum340e-341e-342e.pdf
Intersil (now Renesas)
GMR Isolators' EMC advantages can be traced to their revolutionary spintronic GMR technology. The input drives a low-field generator. The field changes the electron spin polarization, which changes the resistance of the Giant Magneto-Resistor (GMR) bridge elements. Unlike transformers or conventional coils, this does not rely on energy transfer, so EMI emissions are minimal.
https://www.renesas.com/us/en/document/dst/isl71710slhm-datasheet?r=1518186
Seems magnetic
@bohrok2610 Isolation is a no brainer there indeed. It also depends on what you do. You can design a dac with well known parts and make them a whole. Then a good analog test of the output would probably get you very far in verifying it meets expectations, but when like Marcel, all sort of tricks and new circuits are developed, you really need to be able to verify much more, and I can imagine one would justify using an AP more than in the other case.
What was I getting at? I think it stems from low hanging fruit still hanging there, like the power supply for the Amanero.
Mark, maybe replacing the RTZ circuit is a bit much for now, but what about verifying the quality of its power supply and after that setting the Amanero in slave mode and connecting one of the high quality XO`s from that Italian guy?
What was I getting at? I think it stems from low hanging fruit still hanging there, like the power supply for the Amanero.
Mark, maybe replacing the RTZ circuit is a bit much for now, but what about verifying the quality of its power supply and after that setting the Amanero in slave mode and connecting one of the high quality XO`s from that Italian guy?
Mark doesn't use an Amanero.
I used a Fostex FR2-LE field memory recorder (running on batteries) and the GoldWave audio editor for my measurements, by the way. It was probably the most primitive of the three set-ups. I also used a Hameg HM-1505 oscilloscope and a cheap multimeter.
I used a Fostex FR2-LE field memory recorder (running on batteries) and the GoldWave audio editor for my measurements, by the way. It was probably the most primitive of the three set-ups. I also used a Hameg HM-1505 oscilloscope and a cheap multimeter.
On the positive side these discussions and exchanges have yielded a whole trove information and understanding about different related topics (at least for me). Let the debates be positive and not devolve into some shouting match, 🙏
Thank you Joseph for sharing. Just the right amount of treatment for satisfying results. And all these without the use of more elaborate schemes like FIFO or changing USB devices . Very impressive🙂
Both Amanero and I2SoverUSB can work with external master clocks, both for PCM and for DSD. Difference is Amanero requires 22/24MHz whereas I2SoverUSB uses 45/49MHz.
Used a clock multiplier chip to externally clock I2SoverUSB from my 22/24MHz oscillators, then reclocked the I2S output to de-jitter the clock multiplier phase noise.
EDIT: Reason for using a multiplier chip was so that the ratio could be set with jumpers. That way I could use 11/12Mhz clocks or 5/6MHz clocks without a redesign of the board. Just move a jumper.
Used a clock multiplier chip to externally clock I2SoverUSB from my 22/24MHz oscillators, then reclocked the I2S output to de-jitter the clock multiplier phase noise.
EDIT: Reason for using a multiplier chip was so that the ratio could be set with jumpers. That way I could use 11/12Mhz clocks or 5/6MHz clocks without a redesign of the board. Just move a jumper.
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