Mikett, Completely agreed. I have have taken care a few times to point out that Katana may be suitable for people whose needs can be satisfied by an RPi music player type of dac. Although wireless streaming of audio to it may be possible I don't know how close anyone could come to getting it to work successfully as a more general purpose audio dac. The problem of course is that it runs in master mode, which also happens to be the part of the key to its high quality sound. Without any ASRC it doesn't have a guaranteed way to synchronize with streaming input from another clock domain.
Katana has demonstrated that a small mfr CAN come up with something that is good, given its mission. We have not seen this from the chinese suppliers on Ebay etc.
Well if you step back Mark, your work has shown what IS possible. The impediment has always been the construction. Judging by the views the interest in what has been accomplished is there.
My feeling is that a decent DAC kit with a completion price point of say $300 is there. Here's how I think it can be done. From a scaling level, the metalwork is going to be hard to accomplish. We have to see what is available, the acrylic cases that ALLO provides is an option but some might want metal work. Find a case that is widely available on Ebay, Ali etc. Preferably with prepunched holes. Design around that for the connectors etc.
Next, ALLO's work can be reused and leveraged and also the work that You've done.
The concept is a poor man's version of a twisted pear DAC. It looks like ALLO is able to pull this off.
What if we take out the discrete op amp stages with the requisite cost of hand tuning?
What is we simply put in an op amp AVCC with a SOIC and DIP socket arrangement.
What if we simply put in a 3 op amp stage with all single amps like ESS, again make it SOIC or DIP for easy and fun op amp rolling.
Provide jumpers that allow the provision of individual PS for each critical line.
The Q2M series is a nice play DAC because the currents allow circuits to be much easier built.
Allow the potential integration of a 4392 or 4137 in the board.
Allow potential integration of a DSP loop somewhere.
This would be an ideal DAC ecosystem. If it is done right, a NEW DAC comes along say a 9048...maybe we can add that without losing the additional boards.
Anyways, just thinking. If that was there today. I think a number of people would jump in. Already folks want to mod the Katana....it tells you something. A board that has open options for modifications with a price point lower than a Buffalo is sorely needed. If ALLO does not do it, maybe TWISTED PEAR might but I suspect many are looking for such a product. Perfect? No the potential to tweak is a high priority for any DIYEr.
Well if you step back Mark, your work has shown what IS possible. The impediment has always been the construction. Judging by the views the interest in what has been accomplished is there.
My feeling is that a decent DAC kit with a completion price point of say $300 is there. Here's how I think it can be done. From a scaling level, the metalwork is going to be hard to accomplish. We have to see what is available, the acrylic cases that ALLO provides is an option but some might want metal work. Find a case that is widely available on Ebay, Ali etc. Preferably with prepunched holes. Design around that for the connectors etc.
Next, ALLO's work can be reused and leveraged and also the work that You've done.
The concept is a poor man's version of a twisted pear DAC. It looks like ALLO is able to pull this off.
What if we take out the discrete op amp stages with the requisite cost of hand tuning?
What is we simply put in an op amp AVCC with a SOIC and DIP socket arrangement.
What if we simply put in a 3 op amp stage with all single amps like ESS, again make it SOIC or DIP for easy and fun op amp rolling.
Provide jumpers that allow the provision of individual PS for each critical line.
The Q2M series is a nice play DAC because the currents allow circuits to be much easier built.
Allow the potential integration of a 4392 or 4137 in the board.
Allow potential integration of a DSP loop somewhere.
This would be an ideal DAC ecosystem. If it is done right, a NEW DAC comes along say a 9048...maybe we can add that without losing the additional boards.
Anyways, just thinking. If that was there today. I think a number of people would jump in. Already folks want to mod the Katana....it tells you something. A board that has open options for modifications with a price point lower than a Buffalo is sorely needed. If ALLO does not do it, maybe TWISTED PEAR might but I suspect many are looking for such a product. Perfect? No the potential to tweak is a high priority for any DIYEr.
Mike, I don't know much about TP products. Haven't had the opportunity to listen. Also, I don't know about making a dac with the idea of making to mod. It't quite hard to make a really good dac and really easy to mess it up with cool ideas that amount to poor electronics design. As I said before in another post:
"...hardware upsampling architecture with Sabre dacs as described in this thread is only one possible dac system architecture. The approaches taken by Benchmark DAC-3 and Allo Katana are architecturally different from what is described in the this thread and also different from each other. There is more than one way to skin at cat, as it were, but whatever approach is used there are probably many more wrong ways to do it than right ways. Great care and attention to implementation details is necessary no matter which approach is used in order to obtain best sound quality results."
"...hardware upsampling architecture with Sabre dacs as described in this thread is only one possible dac system architecture. The approaches taken by Benchmark DAC-3 and Allo Katana are architecturally different from what is described in the this thread and also different from each other. There is more than one way to skin at cat, as it were, but whatever approach is used there are probably many more wrong ways to do it than right ways. Great care and attention to implementation details is necessary no matter which approach is used in order to obtain best sound quality results."
I just wish there was a better Chinese implementation of the Sabre chips, one that required less mods. Sadly, if such a thing does appear, it will most likely be due to them copying the hard work of others rather than doing some design work of their own.
I am interested in upsampling, I wonder how well one of the SRC boards would work with DAC chips oher than the ESS ones.
I am interested in upsampling, I wonder how well one of the SRC boards would work with DAC chips oher than the ESS ones.
some progress on volumio v2.444 and 9028q2m driver:
green 9028q2m board i2c sda to pi gpio pin 3,
green 9028q2m board i2c scl to pi gpio pin 5,
disable the on board mcu by j1, j2 on,
I can't figure out wich pi gpio pin for res, any comments, suggestions, and solutions are appreciated, but able to get the driver working on half volume, unable to change volume, sq sounds good to me. the driver looks have full control of the dac.
green 9028q2m board i2c sda to pi gpio pin 3,
green 9028q2m board i2c scl to pi gpio pin 5,
disable the on board mcu by j1, j2 on,
I can't figure out wich pi gpio pin for res, any comments, suggestions, and solutions are appreciated, but able to get the driver working on half volume, unable to change volume, sq sounds good to me. the driver looks have full control of the dac.
Attachments
Sure. I think we all can probably agree on that.
Oh, I don't know. It would be fine if they would like to copy anything here I have done.
It turns out there are not all that many different ways to make a good dac, so some things about different designs are probably going to have a lot of similarities. Where things tend to go wrong with dac designs is as soon as the price starts going up a little and more features can be added, most people would far prefer a great looking display, a remote control, and a nice case instead of only getting improved sound quality for that extra money. The dac manufacturers know this very well and make products for which they think there will be good demand.
In particular, manufacturers of Chinese dacs sold on places like ebay know that people come there shopping for bargains. So, they make products that look like bargains, make advertising claims that aren't true, and generally do what it takes to generate some sales. In reality there is no way a $39 dac is going to have -120dB distortion. But there are apparently a lot of people who are willing to suspend disbelief long enough to place an order. When the item arrives and is listened to for the first time, it is only then that the reality starts to set in.
Then some people come to places like this looking for easy fixes: "which opamp can I plug into this to make it sound great?" When they see what is actually involved to get the best of the dac and maybe get to that magic -120dB distortion number, virtually nobody does it all. Although there are probably some people from all over the world who have looked at this thread, I doubt if there are a handful who have done every single mod and done them all with very good layout practices so as to get the best sound quality possible.
Therefore, it would probably be a big improvement to the situation if somebody would just copy a good sounding design, maybe like from here. Otherwise, don't know how most people will ever be able to end up with a good one.
It might be worth trying with one of the better AKM dac chip boards, but there is no magic bullet fix for sound quality, including SRC. The more stuff you fix the better it can sound, assuming one starts out with a top of the line dac chip.
In addition, in order for people to be able to accurately hear the results of their modding efforts I still recommend to people that they mod a LME49600 headphone amp board in order to have something good enough to really hear how their dac mod work is coming along. People may think their existing amp is good enough, but in reality that is unlikely. It it's hard to find a good clean amp just like it is hard to find a good dac. Sorry. Just the way it is, as always IMHO.
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eslei, Don't know where you found information on hooking up Q2M dac to RPi, although I know there is been an unsupported driver around for some time.
There was another thread here at diyaudio about it where maybe somebody would know more about it: Chinese ES9038Q2M DAC Board I2S Drive
There was another thread here at diyaudio about it where maybe somebody would know more about it: Chinese ES9038Q2M DAC Board I2S Drive
@eslei, what is the physical connection the driver assumes for how Q2M is interfaced to RPi?
Does it assume there is I2S only, with four pins: DATA, BCLK, LRCK, GND?
If so, that would mean volume would have to be controlled by adjusting the PCM/I2S data sent to the dac (software volume control) rather than by using the Q2M digital volume control registers (hardware volume). Is that how it is supposed to work?
Does it assume there is I2S only, with four pins: DATA, BCLK, LRCK, GND?
If so, that would mean volume would have to be controlled by adjusting the PCM/I2S data sent to the dac (software volume control) rather than by using the Q2M digital volume control registers (hardware volume). Is that how it is supposed to work?
Okay, I see you want to connect I2C bus for control. RES is for RESET, which the Pi should not need to do. However, J1,J2 on does not disable the on-board mcu, it sets it to I2S/PCM/DSD mode, same as if J1,J2 are both off. If you want to disable the on-board mcu then you must lift the mcu I2C pins as I have shown in previous posts.
http://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-78.html#post5412858
http://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-72.html#post5408825
If you want to see what command Pi might be trying to send by I2C you can use one of these super cheap logic analyzers which are fast enough for I2C, and the software can decode I2C format into hex or decimal instructions thus making it very easy to read the code. New USB Logic Analyzer Device Set USB Cable 24MHz 8CH 24MHz for ARM FPGA M100 7000000492822 | eBay
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i2c hardware volume, the code can be seen from a digital oscilloscope.
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Janos_904
I bought this Chinese SRPP:Aiyima Updated Tube Amp Preamp 6N3 Vacuum Tube PreAmplifier SRPP Board Diy Kits Fit for 5670-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
There is also the scheme
I used capacitors Mundorf MCap EVO Oil 2,2uF 450V and Jantzen SUPERIOR Z-Cap MKP 0.47uF 800v.
The valves are GE 5670 Triple Mica of 1956.
The heaters supply is DC.
I have also added a stereo potentiometer to avoid distortion.
The sound of the original SRPP is terrible
However, based on my experience, the solid state has much lower distortions; but if you like the sound of the tubes this seems like a good solution.
I bought this Chinese SRPP:Aiyima Updated Tube Amp Preamp 6N3 Vacuum Tube PreAmplifier SRPP Board Diy Kits Fit for 5670-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
There is also the scheme
I used capacitors Mundorf MCap EVO Oil 2,2uF 450V and Jantzen SUPERIOR Z-Cap MKP 0.47uF 800v.
The valves are GE 5670 Triple Mica of 1956.
The heaters supply is DC.
I have also added a stereo potentiometer to avoid distortion.
The sound of the original SRPP is terrible
However, based on my experience, the solid state has much lower distortions; but if you like the sound of the tubes this seems like a good solution.
@oversimon, Are you planning to use the tube preamp with your Chinese dac? If so, how will you connect the SRPP input to the dac? And where does will the output go, to some power amplifier?
Also, I guess I might ask if you are planning to use it with a dac, why bother? It certainly can't fix most of the problems with a stock dac, and it can't make a well modded dac become more true to whatever is on a record.
Note: For those readers not familiar with an SRPP preamp, it is a tube amplifier circuit with a funny name that has been studied by a number of people. Merlin Blencowe's article is probably as good an introduction as any: http://www.valvewizard.co.uk/SRPP_Blencowe.pdf
Another take on it can be found here: http://www.tubecad.com/articles_2002/SRPP_Deconstructed/SRPP_Deconstructed.pdf
Also, I guess I might ask if you are planning to use it with a dac, why bother? It certainly can't fix most of the problems with a stock dac, and it can't make a well modded dac become more true to whatever is on a record.
Note: For those readers not familiar with an SRPP preamp, it is a tube amplifier circuit with a funny name that has been studied by a number of people. Merlin Blencowe's article is probably as good an introduction as any: http://www.valvewizard.co.uk/SRPP_Blencowe.pdf
Another take on it can be found here: http://www.tubecad.com/articles_2002/SRPP_Deconstructed/SRPP_Deconstructed.pdf
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@Markw4
Your solution (oscillator, reclocker, 3 opamp on output) is the best and I advise everyone to follow your instructions.
I'm just doing experiments, I'm not an engineer (For listening I use an UDA38PRO).
Before I tried to connect the SRPP directly to the output of the chip bypassing the opamp and now it is connected after the opamp, there are no big differences without opamp.
I've soldered it after the final output stage capacitors so now I can also try my opamps and examine the differences in the sound.
The SRPP is connected to an integrated amplifier, for this reason I use a potentiometer, to have gain comparable to an opamp.
But I can say that now the sound is good, even if I remove the opamp, and is similar to the UDA38PRO.
Without the tubes buffer sounds harsh, with tubes is warm, I think for the 2nd harmonic.
I repeat, they are only experiments and I communicate my impressions, I do not want to advise anyone to do the same
Follow the advice of Markw4 !!!
(sorry for my english, it's terrible)
Your solution (oscillator, reclocker, 3 opamp on output) is the best and I advise everyone to follow your instructions.
I'm just doing experiments, I'm not an engineer
(For listening I use an UDA38PRO).Before I tried to connect the SRPP directly to the output of the chip bypassing the opamp and now it is connected after the opamp, there are no big differences without opamp.
I've soldered it after the final output stage capacitors so now I can also try my opamps and examine the differences in the sound.
The SRPP is connected to an integrated amplifier, for this reason I use a potentiometer, to have gain comparable to an opamp.
But I can say that now the sound is good, even if I remove the opamp, and is similar to the UDA38PRO.
Without the tubes buffer sounds harsh, with tubes is warm, I think for the 2nd harmonic.
I repeat, they are only experiments and I communicate my impressions, I do not want to advise anyone to do the same
Follow the advice of Markw4 !!!
(sorry for my english, it's terrible)
oversimon, Thank you for your very kind words. I don't know what else to say. Well, except maybe that I'm not too sure about where to go next from here. I kind of have some interest in seeing what else can be done with interpolation filtering. While I keep thinking about that for awhile, I will continue to be available for answering any questions that I can. There will be some more about Katana too, sometime after the isolator comes. The essence of it though probably won't be much more than what I have said already. It's a good dac at a good price if an RPi music player is okay for what you need, and, yes, you still might want to mod an LME49600 headphone amp. There is reason I recommend that one: it is more revealing than most, what some people call 'resolving.' Just do it, somebody please, and let us all know what you think.
There's a new board available using the ES9038Q2M:
NEW ES9038Q2M DAC Decoder IIS dsd 384k dop128 | eBay
Hopefully it's a better design than the existing crappy one.
NEW ES9038Q2M DAC Decoder IIS dsd 384k dop128 | eBay
Hopefully it's a better design than the existing crappy one.
Judging by the image and the Menu switch, probably the filters will be selected by pushbuttons? Looks like there are two 3.3V regulators now?