And those concerns are? Could you pm me if it is inconvenient to discuss it here? Many thanks.
I have their AK4495, AK4497 and AD1856 boards as well. All of them sound nice to me. But I don't have their ES9028pro, so don't have anything to share about that board.
Hi asilker,
MSB is meant to further reduce AD1862's distortion when not playing at full volume. According to AD1862 data sheet, MSB can't improve distortion for full volume. I have left the trimmer and the 470k resistors unpopulated on my board as per miro's suggestion, because I always play at full volume to benefit from AD1862's maximum performance.
Yes, 1/4w resistors are more than adequate.
Hidy
Hidy thanks, that's the info I was looking for!
I'll be building the 1.3 with the jl sounds board not flipped and powered by a PSU2.
Is there anyone who would like to convince my to build a second PSU2 board? I'm thinking I could power:
DAC with one independent PSU board 12 and 5
Second board handles the analog 12v stage and whole jl board 5v.
But I also recall Miro saying "make it as simple as possible and no simpler".
Would anyone go to bat for noticable gains by isolating power supplies, or is it something that tickles the brain more than the ears?
I'll be building the 1.3 with the jl sounds board not flipped and powered by a PSU2.
Is there anyone who would like to convince my to build a second PSU2 board? I'm thinking I could power:
DAC with one independent PSU board 12 and 5
Second board handles the analog 12v stage and whole jl board 5v.
But I also recall Miro saying "make it as simple as possible and no simpler".
Would anyone go to bat for noticable gains by isolating power supplies, or is it something that tickles the brain more than the ears?
I put 1nF capacitor between the leg 2 and 3 of the AD797. I have also replaced C31 and C36 from 47pF to 68pF and I have added the 100R resistors serial with them. Unfortunately I did the modifications at the same time, but I can confirm, sound much better, the level of fine details are not comparable. So this modification is highly recommended for AD797, thanks Hidy
ABTG can be used in -40°C environment.
You can use these from mouser:
863-MC7805CTG
863-MC7905CTG
863-MC7812CTG
863-MC7912CTG
C offers some improvement in ripple rejection
I slightly shorted the original quote:
The main reason why diyinhk sounds different is, that is uses double opamp. First part from this opamp is used for I/V conversion, the second part is used as a filter (maybe sallen-key filter?). This filter makes a big difference in the sound and not only to the better. Many details my be lost due to various intermodulation distortions which may arise. The sound will vary according to the selected capacitors, resistors (types and values). This filter can be added as a separate PCB. The combination possibilities of the sound then increase exponentially
It is not due to the stop-clock mechanism.
Thank you for the valuable info about the AD797 (and perhaps many other opamps as well, people can try it and listen for improvements)
The main reason why diyinhk sounds different is, that is uses double opamp. First part from this opamp is used for I/V conversion, the second part is used as a filter (maybe sallen-key filter?). This filter makes a big difference in the sound and not only to the better. Many details my be lost due to various intermodulation distortions which may arise. The sound will vary according to the selected capacitors, resistors (types and values). This filter can be added as a separate PCB. The combination possibilities of the sound then increase exponentially
It is not due to the stop-clock mechanism.
Thank you for the valuable info about the AD797 (and perhaps many other opamps as well, people can try it and listen for improvements)
The sound highly depends on the used opamp, the difference is really huge.
If double (in diyinhk) opamp sounds good, it doesn't mean the single (in this DAC) version provides the same sound impression
My DACs can be highly moded. It has solid GND, digital section is separated from analog. Shift registers can be replaced by another conversion technique. Moreover anyone can make gerber files for a better version, and I will pin it on the main page, people can build
@asilker Hard to say if you find some improvements with separating PSU. But you can try, separate digital PSU from analog PSU
One PSU +-5V for DAC digital + jlsounds
Second PSU +-12V for DAC analog
Thinking hard about it!
Miro thanks for your continued guidance. The farther I get into things, the more impressed I am that someone (you) fabricated this and released it into the world. This build is a blast, I love testing my skills and knowledge. FUN!
Hi gaszto,
I just tried 100pf C0G plus 100R metal film resistors paralleled with 1.5k feedback resistor. I used 1000pf input shunt caps. I can confirm that it works well with all these opamps that I have tried so far: AD797, Sparkoslab 3601, Ada4627-1 and LM6171. There are various degrees of improvement with different op amps.
The resolution has been improved. Only that I caught two glitches in two of my favorite songs that I had never noticed before, even with diyinhk dac. I used a third dac to verify that the gliches are indeed in the recordings if I listen attentively and know what to listen for.
These glitches could have easily gone unnoticed before, but now they are so ugly sounding and intrusive with my miro's dac that for a moment I have been very sad for the loss of two favorite songs.
Hidy
Hi asiker,
I am using 1.3 version. If I were you, I would use one 12V for AD1862 and a separate 12V for the opamps. I am not using PSU2, but I am also using liner regulators (LT3045). I have observed that the dac's analog part and the opamps are fighting for current. This is obvious once I remove all the 100uf caps. Why removing the 100uf caps? Because they color the sound, no matter what caps you use. I have heard for myself how it sounds without caps.
Now, after removing the caps, the liner regulator is regulating the AD1862 directly and efficiently. Using an oscilloscope, I can see that the voltages at my AD1862 are supper smooth. It is almost a steady straight line, with only small fluctuations of peek to peek voltages of 20mv. This is beautiful, compared to what I get when the 100 uf caps are in place. With the caps, the peek to peek voltage change is also 20mv, but it is a constant jagged line. The voltage keeps going up and down, even when not playing music. You can see for yourself in the data sheets of the linear regulators that they perform better without big caps between the regulators and the powered unit.
Now, all this is beautiful, except the averaging voltage measured at my AD1862 is now only 11.02V, as compared to 12.02V when the caps are in place, meanwhile, the voltage at the opamp is jumping between 12.02V and 12.08V when using LM6171s. Apparently, the AD1862 is starved while the opamps are over supplied.
I could have easily solved this if I had separate 12V power supplies for AD1862 and opamps respectively.
But, unfortunately, my dac is in a case that is too small to allow a second 12V PSU. So I have to try balancing the current needs of two circuits with only one supply. I added 2 x 4.7 uf film caps at each of my AD1862 power pins and successfully brought the average voltage back to 12V while still maintaining the beautiful straight voltage line even under load. The voltages at the opamps were steady as well. I was happy because I got better voltage performances and also got rid of the sound colors of the 100 uf caps.
All this was good until my discrete SS3601 opamps arrived. Compared to LM6171s, these SS3601 are power monsters. Once I put them in, the delicate equilibrium I established before was totally destroyed. Now, the opamps were starved of current. Their voltages went down to 11V and were fluctuating wildly. Now, I had to add capacitance to the opamps power pins. But this time, I didn't succeed in striking a perfect balance of current supplies between the dac and the opamp.
In the end, I put back all my 8 x 100 uf caps and I was back at where I started. My adventure ended and I failed. Sad, but I tried. I tried hard.
All I can say is, if you have 2 separate 12V power supplies, you don't have to fail like I did. You don't have to put up with the sound colors of your 100 uf caps. You don't have to put up with the constant voltage fluctuations they send to your DAC. Your liner regulators will thank you too, because by removing the big capacitors, you are allowing them to have direct control of their circuits and thus performing the best they can.
What a beautiful world that would be.
Thank you.
Hidy
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Hidy, that's a strong case!
Wrong, see edit below: I assume you're talking about the 100uf /25v smoothing caps that come after the regulators? (C27+28 on PSU2)
If that's the case, is there any chance that those are the same caps that cause the oscillation instability that necessitates 2k2 on the rails?
If I could delete those caps AND delete the 2k2 resistors, then I think I'm sold
EDIT: NOPE you're talking about c7-10 and c17-20 on the DAC board right next to the ad1862.
Same question though, do these contribute to the oscillation?
Wrong, see edit below: I assume you're talking about the 100uf /25v smoothing caps that come after the regulators? (C27+28 on PSU2)
If that's the case, is there any chance that those are the same caps that cause the oscillation instability that necessitates 2k2 on the rails?
If I could delete those caps AND delete the 2k2 resistors, then I think I'm sold
EDIT: NOPE you're talking about c7-10 and c17-20 on the DAC board right next to the ad1862.
Same question though, do these contribute to the oscillation?
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