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Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 KHz

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Joined 2005
Chrisnew : the output for the RCAs is the 4 vias in the middle between the balanced output ! You connected the Single Ended on the Balanced output ! Look at the shematic : link in first page of this thread !

Can you photograph the Powersupply please ? And give the unloaded voltage at the output of your PS ?

The outer headers can be used for opamp buffered Single Ended/RCA. The Hifidunio page might have caused confusion as it indicates the outer pads only. I think correct hook up would be to the +ve and gnd pads on both left and right channels as the -ve pad is an inverted signal.

The middle header is for direct output from the resistor ladder.
 
Has anyone tried the filter bypass settings? And if so how is it done? Also are the original FIR filters included in the 0.9 firmware update, so if you wish to experiment with custom filters you can reload Sorens at a later date?

I am also interested in knowing if there is any provision to make the DAC filterless with the current firmware? Any filter on/off control via serial port? Oversampling on/off?
 
Has anyone tried the filter bypass settings? And if so how is it done? Also are the original FIR filters included in the 0.9 firmware update, so if you wish to experiment with custom filters you can reload Sorens at a later date?

Current firmware already supports custom filters, incl. bypass....

I'm working on the manual and will release manual and filter utility soon.
 
The outer headers can be used for opamp buffered Single Ended/RCA. The Hifidunio page might have caused confusion as it indicates the outer pads only. I think correct hook up would be to the +ve and gnd pads on both left and right channels as the -ve pad is an inverted signal.

The middle header is for direct output from the resistor ladder.

Thanks for this hint !

ANybody compare the direct SE with the bufered one (I really believed the oaps were only for balanced output:eek: !)
 
Hi Soekris, in your upcoming firmware update, the DSD support portion. Is it possible to program the dac to accept 2.844mhz 1bit signal and just use the whole 28bit as as 1bit dac. As in your previous posts the digital filter already output to around 3mhz?

In this way it is pure DSD decoding, no digital filter at all.

Is it possible or. I am missing something here? Thank you. Cheers.


Sent from my iPhone using Tapatalk
 
My humble conclusion

Okay so here it is, my humble conclusion, or should I say verdict, of the sound quality of the dam1021-01 after it has been running for more than a week straight.
I have only been using the isolated I2S in via the Amanero board and I have tested both the balanced XLR outputs and the raw SE rca outputs at J7. Haven’t had the chance to use the other inputs yet. Also I’m still on the original firmware (not that it matters in terms of SQ).

Various sorts of music have been played, acoustic jazz and classical, rock, pop and some electronica. Some of these are regarded as ‘audiophile’ material and some not. Some material are genuine stereo miked recordings, others are typical modern studio layered recordings. A lot of well known music that I use when I test the SQ of different equipment. Uncompressed 44.1, 88, 96, 192 and even some higher res. as well as mp3 320Khz.

In his first post Søren aimed high, hinting at R2R-ladder dacs as totalDac and MSB. So naturally my hopes were high having owned a non-oversampling Discreet Monica R2R-ladder dac myself, as well as having heard the absolutely outstanding totalDac.

Now, the first thing that struck me with this dac was the harsh digital sound it produced. Okay, it had only been running for a few minutes so that was to be expected. Unfortunately this still hasn’t changed to a degree I had hoped for.

Most music sounds quite flat, the image is 2D, lacking depth and calmness. Not at all the 3D sensation or holographic image which are the trademarks of an R2R dac. There are however, a lot of details. But it doesn’t transcend into the sense of the acoustics of the recording room or the texture of the instruments or the sensation of space between the instruments.

Lots of details yes, but when presented with complex multilayered music such as Carl Nielsens' 5th it can't keep the grip and the composition sort of collapses. It's hard to really decipher the instrument groups and the notes each group is playing. At times the 5th sounds somewhat chaotic. The dac fares better with smaller ensembles, though the placement of each instrument is not always crystal clear. The soundstage is simply too wide IMO - very left-rightish.
With both my old Discreet Monica and the totalDac you instantaneously go ‘Yes, there it is’! Your heart is at rest. There is really no need to describe the experience of those dacs much further, as music is being played as it should be, effortlessly and naturally. Dacs like these make all other dacs, including dam-1021, sound like they are struggling. You’re listening to music while with the dam-1021 I still find myself listening to a piece of equipment.

To my ears the frequency spectrum is not flat. I hear an emphasis on the upper mid and treble region that makes, for instance brass and horn sections, and even sometimes solo saxophones, sound metallic. Very unpleasant to my ears.

Another thing that really bugs me with this dac is the aggressive in-your-face signature. I suspect there is a connection between its forwardness and the biased frequency spactrum? Maybe exchanging the caps would help in this respect?

It does however, seem to benefit from a tube amplication. I would like to hear how it performs swapping the ceramic(?) caps and maybe another clock than the Si514 if it’s applicable. Also different output stages, a Lundahl trafo or a tubed one.

It’s still not really clear to me whether there is a default FIR filter installed or if it’s bypassed? And will it be possible to deactivate oversampling altogether although Søren advises against it?

Is there anyone here who’ve tried to mess around with different FIR filters with this dac?

Anybody in this forum who have heard or own a totalDac (or any other R2R-ladder dac) are welcome to chime in after hearing the soekris dac.

I’m sorry to drop this bomb but my hopes are that we’ll all end up with a product that can really compete with the totalDac & MSB, for the benefit of all diy’ers who cannot afford a totalDac or the like - and enjoy tailormade electrical toys. Maybe there is a basis for doing some experimental modding on the existing dac or for Søren to work on a vers. 2?

Is it a bad dac then? No far from it. It just doesn't meet my expectations of an R2R-ladder dac. It’s at least on par with a lot of mid-priced commercial delta-sigma dacs.

Finally let me stress that I still highly value all the effort and hard work Søren has put into this project.
 
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It is great that you speak honestly about what you hear, people usually keep silence in a weird attempt not to disappoint the designer and I think your input is much more valuable than the silence of those who do not like it.

This is a DIY forum. Most people here have yeas of experience in tweaking digital and all sorts of devices and I have heard people saying that this and that is not good in this DACs design, IMHO it will be very useful for Soeren to check with reality about some of his design choices. Obviously he is very smart and talented and it would be great if this board evolves in something to challenge the TotalDAC,it sure has potential in the areas of DSD and crossover implementation as well.

I am hoping to listen to the board that I have this weekend, I will sure do what you did - honestly describe what I hear while trying to be objective in this subjective attempt. I prefer this than just selling the board at half price and moving to the next.
 
Okay so here it is, my humble conclusion, or should I say verdict, of the sound quality of the dam1021-01 after it has been running for more than a week straight.
I have only been using the isolated I2S in via the Amanero board and I have tested both the balanced XLR outputs and the raw SE rca outputs at J7. Haven’t had the chance to use the other inputs yet. Also I’m still on the original firmware (not that it matters in terms of SQ).

Various sorts of music have been played, acoustic jazz and classical, rock, pop and some electronica. Some of these are regarded as ‘audiophile’ material and some not. Some material are genuine stereo miked recordings, others are typical modern studio layered recordings. A lot of well known music that I use when I test the SQ of different equipment. Uncompressed 44.1, 88, 96, 192 and even some higher res. as well as mp3 320Khz.

In his first post Søren aimed high, hinting at R2R-ladder dacs as totalDac and MSB. So naturally my hopes were high having owned a non-oversampling Discreet Monica R2R-ladder dac myself, as well as having heard the absolutely outstanding totalDac.

Now, the first thing that struck me with this dac was the harsh digital sound it produced. Okay, it had only been running for a few minutes so that was to be expected. Unfortunately this still hasn’t changed to a degree I had hoped for.

Most music sounds quite flat, the image is 2D, lacking depth and calmness. Not at all the 3D sensation or holographic image which are the trademarks of an R2R dac. There are however, a lot of details. But it doesn’t transcend into the sense of the acoustics of the recording room or the texture of the instruments or the sensation of space between the instruments.

Lots of details yes, but when presented with complex multilayered music such as Carl Nielsens' 5th it can't keep the grip and the composition sort of collapses. It's hard to really decipher the instrument groups and the notes each group is playing. At times the 5th sounds somewhat chaotic. The dac fares better with smaller ensembles, though the placement of each instrument is not always crystal clear. The soundstage is simply too wide IMO - very left-rightish.
With both my old Discreet Monica and the totalDac you instantaneously go ‘Yes, there it is’! Your heart is at rest. There is really no need to describe the experience of those dacs much further, as music is being played as it should be, effortlessly and naturally. Dacs like these make all other dacs, including dam-1021, sound like they are struggling. You’re listening to music while with the dam-1021 I still find myself listening to a piece of equipment.

To my ears the frequency spectrum is not flat. I hear an emphasis on the upper mid and treble region that makes, for instance brass and horn sections, and even sometimes solo saxophones, sound metallic. Very unpleasant to my ears.

Another thing that really bugs me with this dac is the aggressive in-your-face signature. I suspect there is a connection between its forwardness and the biased frequency spactrum? Maybe exchanging the caps would help in this respect?

It does however, seem to benefit from a tube amplication. I would like to hear how it performs swapping the ceramic(?) caps and maybe another clock than the Si514 if it’s applicable. Also different output stages, a Lundahl trafo or a tubed one.

It’s still not really clear to me whether there is a default FIR filter installed or if it’s bypassed? And will it be possible to deactivate oversampling altogether although Søren advises against it?

Is there anyone here who’ve tried to mess around with different FIR filters with this dac?

Anybody in this forum who have heard or own a totalDac (or any other R2R-ladder dac) are welcome to chime in after hearing the soekris dac.

I’m sorry to drop this bomb but my hopes are that we’ll all end up with a product that can really compete with the totalDac & MSB, for the benefit of all diy’ers who cannot afford a totalDac or the like - and enjoy tailormade electrical toys. Maybe there is a basis for doing some experimental modding on the existing dac or for Søren to work on a vers. 2?

Is it a bad dac then? No far from it. It just doesn't meet my expectations of an R2R-ladder dac. It’s at least on par with a lot of mid-priced commercial delta-sigma dacs.

Finally let me stress that I still highly value all the effort and hard work Søren has put into this project.


Can you please share details on what amplification you used - or anything else in the signal chain?
 
I wouldn't be so quick about final conclusions. Firmware still needs to be perfected, there are a lot of filters etc. I hope that, over time, your impression will change. I still don't have the board because of other priorities, but I'm planning to buy it and I wish that my conclusion about sound will be different :)
 
I have managed to interface my Arduino to the DAC using a MAX232 IC.

attachment.php


However, I am getting erratic behaviour. When I power everything up, everything works just fine, but after a while (a few minutes? I'm not sure) the communication seems to break down. I am not able to either send or receive data. I suspect that it has something to do with some "power saving" feature. Is there a way to disable power saving on the DAC's side?

My arduino has no problem communicating with my PC through my MAX232 and my USB to Serial adapter with no such problems. Also, my USB to Serial adapter has no problem communicating with the DAC. I only have problems with the Arduino talking to the DAC.
 

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Joined 2005
Okay so here it is, my humble conclusion, or should I say verdict, of the sound quality of the dam1021-01 after it has been running for more than a week straight.

Sebastian,

I've seen you say this previously and like others felt you had a problem with your setup, so I had a look at the specs of the gear you mentioned.

You've stated you were using a CMA800R Headphone Amplifier and a Stax headphone amp.

The CMA800R has an input sensitivity of 1.2Vrms while the Soekris has a SE output of 1.4Vrms and balanced output of 4Vrms. In both balanced and SE configs you would be overloading the input of the CMA800R.

The Stax 006t - which you noted sounded very musical - has a maximum input level of Max. Input Level at minimum volume level of 30V.

Okay, so just by chance I swapped in my Senn stats and the Stax amp that has a tube output stage. (balanced input).
Accidentally I played a rock music track by Beck from Guero album (a music genre that not normally suits the Senns IMO). Lo and behold. All of the above impressions didn’t apply anymore!
Frequency spectre was much more linear w. a bass punch I’ve seldom heard from this setup. Lovely airy separation between instruments, more holographic like the r2r’s I’m used to. More laid back presentation. Quite relaxed.
In short, the whole system was playing MUSIC. Effortlessly.


It seems to me that you are bagging out the DAM1021 because you are overloading one of your headphone amps - which is hardly the fault of the DAC.

For reference these are Sebastian's previous comments on harshness which detail gear used:

http://www.diyaudio.com/forums/vend...e-24-bit-384-khz-post4202758.html#post4202758

http://www.diyaudio.com/forums/vend...-magnitude-24-bit-384-khz-23.html#post4203982
 
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