Yes, I see the "recommendation". However in nige2000's picture he did not stack his boards and he also heard the low level noise. I can remove the standoffs and just leave the pins connecting the two boards. I doubt that it would make any difference but I supposed I won't know until I try it.
I may try it in a few days. I am happy listening to my TDA1541A right now so I have no desire to go back to the DA M1's low level noise.
I may try it in a few days. I am happy listening to my TDA1541A right now so I have no desire to go back to the DA M1's low level noise.
I did not go back and look at what Nigel did. I do know he threw it together since he is involved in a gigantic amplifier project. I know he inserted a reclocker into the thing and found improvement but not nirvana.
Whenever the mood strikes ... I would not do it either.
Hoping the push/pull version doesn't so the same thing.
Could sharing the same power supply be part of the problem?
I won't be doing this for a couple of weeks.
Whenever the mood strikes ... I would not do it either.
Hoping the push/pull version doesn't so the same thing.
Could sharing the same power supply be part of the problem?
I won't be doing this for a couple of weeks.
My stereo two-board dac is now a one channel push-pull dac. It still has the same power supply and r-c/c-r filter output.
The low level noise is gone, and the sound is pretty good, even though I am only listening to the left channel. Initial impression is that it is similar in sound to my TDA1541A dac, but maybe a bit more forward. The difference may be due to the tube gain stage that I use to raise the TDA1541A output voltage, or it may be TDA1541A technology vs Audio-gd discrete resistor ladders and FPGA, or other reasons.
Right now I don't have the urge to rip it out of my system and put the TDA1541A back in. Since I was quite happy with my TDA1541A dac and I only bought the DA M1 boards out of curiosity and not because I wanted to replace my TDA dac, this is a good thing. Now I need another channel.
The question now is did I mess up with the simple stereo dac setup to get the annoying low level noise, or was that inherent in the design and a push-pull setup is required for optimal performance? I suppose time will tell as other diyers try these boards.
The low level noise is gone, and the sound is pretty good, even though I am only listening to the left channel. Initial impression is that it is similar in sound to my TDA1541A dac, but maybe a bit more forward. The difference may be due to the tube gain stage that I use to raise the TDA1541A output voltage, or it may be TDA1541A technology vs Audio-gd discrete resistor ladders and FPGA, or other reasons.
Right now I don't have the urge to rip it out of my system and put the TDA1541A back in. Since I was quite happy with my TDA1541A dac and I only bought the DA M1 boards out of curiosity and not because I wanted to replace my TDA dac, this is a good thing. Now I need another channel.
The question now is did I mess up with the simple stereo dac setup to get the annoying low level noise, or was that inherent in the design and a push-pull setup is required for optimal performance? I suppose time will tell as other diyers try these boards.
I do think the designer intends this to be used in the push/pull configuration since his intention was to mimic the 1704.
I am big on separate supplies so I wonder if there could have been some strange interaction with both powered by the same supply? I am tempted to power analog and digital sections separately. When something is distilled down to as little as this DAC power supply becomes really important in my experience.
Now you have me excited.
i ordered some of their power supplies so that is why I am waiting to proceed. Great price for shunt regs and I get the feeling this fellow is very good at what he is doing so i thought I should give them a try.
THANKS for your report!
Take care,
I am big on separate supplies so I wonder if there could have been some strange interaction with both powered by the same supply? I am tempted to power analog and digital sections separately. When something is distilled down to as little as this DAC power supply becomes really important in my experience.
Now you have me excited.
i ordered some of their power supplies so that is why I am waiting to proceed. Great price for shunt regs and I get the feeling this fellow is very good at what he is doing so i thought I should give them a try.
THANKS for your report!
Take care,
Quite possible that the low level noise was due to grounding issues - with a DAC you have digital currents flowing in the 0V and they may well share common impedance with the analog 0V without fastidious attention to detail. Once you run balanced the grounding issues are taken care of by the CMRR of your next stage.
According to Audio-gd:
"4 pcs modules built the NOS DAC with IIS input and working with Push / pull mode : Every channel had 2 pcs modules and the J1 must with jumpers , 1 pc module must push into a jumper to J2 for setting working for negative wave .Another module without jumper on J2 for working as positive wave . Every channel had connect J81 to J106 (The J104 and J105 can short by tins), PINA and PINB. The input signal and output signal just want to connect from one module."
I believe his intent is to mimic the PCM1704's sign magnitude architecture to eliminate zero crossing glitches.
"4 pcs modules built the NOS DAC with IIS input and working with Push / pull mode : Every channel had 2 pcs modules and the J1 must with jumpers , 1 pc module must push into a jumper to J2 for setting working for negative wave .Another module without jumper on J2 for working as positive wave . Every channel had connect J81 to J106 (The J104 and J105 can short by tins), PINA and PINB. The input signal and output signal just want to connect from one module."
I believe his intent is to mimic the PCM1704's sign magnitude architecture to eliminate zero crossing glitches.
Ah I see to some extent, my original assumption about balanced was incorrect, apologies. I can understand the sign-magnitude architecture (used originally in PCM63 as 'co-linear') but cannot yet see how its possible to convert a pure R2R type DAC to be push-pull. Without a schematic I can't make sense of the text you've quoted from Audio-gd.
I'm now completely unclear how this method of interconnecting two DACs solved your noise problem. But happy that it does nevertheless
I'm now completely unclear how this method of interconnecting two DACs solved your noise problem. But happy that it does nevertheless
It's not listed in discontinued section so hopefully it means he is revising the design. Both nige and Ben Mah experienced hum so maybe that's being remedied?
OT: I was revisiting old posts on the Hammond 193 series chokes and saw you used them as well. Just added mine back in my projection setup. Wow...
No one wants to talk about this DAC so we might as well talk about HAMMOND chokes!
When this first came up I thought the whole thing was stupid. Otherwise known as not wanting to spend the money. A few years later my interests turned to the AC so I tried a few 5H 250mA HAMMONDS I had laying about and was amazed at what happened. If only ALL tweaks were as effective as that! Ended up buying six of the recommended chokes, can't remember the letter.
I know Los Angeles is a big place but have you ever run into fellow Los Angelean (is that what you call yourselves? I took a guess) Rancy Tsuch (his abbreviated surname)? I would bet you two would find some common audio ground.
Was hoping the AUDIO G-D DAC would have been the upgrade from the SOEKRIS. Still have not got mine working. I got some of the shunt regs from them, nicely assembled bu I have not tried to use them yet. They are very nice people and are willing to answer questions. I should write and ask what they are up to.
Take care,
When this first came up I thought the whole thing was stupid. Otherwise known as not wanting to spend the money. A few years later my interests turned to the AC so I tried a few 5H 250mA HAMMONDS I had laying about and was amazed at what happened. If only ALL tweaks were as effective as that! Ended up buying six of the recommended chokes, can't remember the letter.
I know Los Angeles is a big place but have you ever run into fellow Los Angelean (is that what you call yourselves? I took a guess) Rancy Tsuch (his abbreviated surname)? I would bet you two would find some common audio ground.
Was hoping the AUDIO G-D DAC would have been the upgrade from the SOEKRIS. Still have not got mine working. I got some of the shunt regs from them, nicely assembled bu I have not tried to use them yet. They are very nice people and are willing to answer questions. I should write and ask what they are up to.
Take care,
It was low level noise rather than hum that was the issue with one board per channel. When I connected them in what Audio-gd calls push-pull mode with two boards per channel, the noise went away.
I listened to a four board push-pull setup for about two months. Unfortunately I only had one 3.3v low noise regulator (TPs7A4700) board to supply power to all four boards, so the power supply situation was not the best. Compared to my TDA1541a, the DA-M1 had some harshness in the high end, sounding less smooth. This may or may not be improved upon with separate analog and digital supplies. At some point I will try it again with separate supplies.
During my extended period of listening, I found the DA-M1 acceptable but the harshness was noticeable, although it did not stop me from enjoying the music. There was no problem with listening for long durations - it was not fatiguing. However, with my TDA1541a back in, I definitely prefer it over the DA-M1 setup. Both setups were fed with digital from Iancanada fifo so the comparision was between the dacs only.
I also noticed that the Audio-gd website no long offers the two board Singularity 19 dac. Maybe they also had issues with the two board setup.
I listened to a four board push-pull setup for about two months. Unfortunately I only had one 3.3v low noise regulator (TPs7A4700) board to supply power to all four boards, so the power supply situation was not the best. Compared to my TDA1541a, the DA-M1 had some harshness in the high end, sounding less smooth. This may or may not be improved upon with separate analog and digital supplies. At some point I will try it again with separate supplies.
During my extended period of listening, I found the DA-M1 acceptable but the harshness was noticeable, although it did not stop me from enjoying the music. There was no problem with listening for long durations - it was not fatiguing. However, with my TDA1541a back in, I definitely prefer it over the DA-M1 setup. Both setups were fed with digital from Iancanada fifo so the comparision was between the dacs only.
I also noticed that the Audio-gd website no long offers the two board Singularity 19 dac. Maybe they also had issues with the two board setup.
I was hoping this would have been the board for us kooks to turn into silk purses.
Now there is almost no chance. I do enjoy the give and take of a number of determined DIY tinkerers working on the same circuit.
Sent a note to Kingwa asking what the future holds for R2R DACs from his company.
Now there is almost no chance. I do enjoy the give and take of a number of determined DIY tinkerers working on the same circuit.
Sent a note to Kingwa asking what the future holds for R2R DACs from his company.
I think I took a phone call while writing this post.
What I intended to say was that he did not say if he had REVISED the board or had any intention of doing so. He is a very kind fellow, you can tell from his notes but he does elaborate and knowing how much email he gets I am hesitant to ask too much.
I guess we will see in fullness of time as Sir Humphrey Appleby would tell the minister when he did not want to tell him anything. Assuming everyone (ha ha) who reads this is a fan of Yes, Minister one of the greatest TV shows of all time.
Alas, I moved just as I discovered Randy's web page. I'm now in the Midwest...
thanks for the follow up everyone. Good to know the boards are still available...
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