Super Regulator and Salas Shunt Regulator have Low impedance variation with current variation, but not possible 4 v. out.
8 vol is possible. I can bootstrapping OP amp. +8 vol. to make floating mass. I simulate with AD797. But need OP Amp that can work to +4 -4 vol. And 0 dB stable.
8 vol is possible. I can bootstrapping OP amp. +8 vol. to make floating mass. I simulate with AD797. But need OP Amp that can work to +4 -4 vol. And 0 dB stable.
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Listening test - different mods
Hi,
Me and a fried just listened and compared our DACs in different status of modifications. The difference between the 2 dacs are the power supplies.
Mods to both dacs: Factory mod 0.1 + 0.1R, 16 cap mod 16x680/10, Output capacitor changed to film types, Opamps removed, Party-Pak slow filter.
Dac 1: DC supply on J1 +-12VDC, Simple unregulated DC supply.
Dac 2: 6.5V DC on J1, 5V regs removed, +- 5VDC supplied on caps after 5V regs. Placid shut regulator is used for the 6.5V and a JSR-06 super regulator for the +-5V.
To sum it up - not much difference! Both sounded great.
If we get into bearly audible (or imagined) differences: Dac 2 - slightly sweeter and a bit more relaxed; Dac 1 - a bit brighter.
Ulf
Hi,
Me and a fried just listened and compared our DACs in different status of modifications. The difference between the 2 dacs are the power supplies.
Mods to both dacs: Factory mod 0.1 + 0.1R, 16 cap mod 16x680/10, Output capacitor changed to film types, Opamps removed, Party-Pak slow filter.
Dac 1: DC supply on J1 +-12VDC, Simple unregulated DC supply.
Dac 2: 6.5V DC on J1, 5V regs removed, +- 5VDC supplied on caps after 5V regs. Placid shut regulator is used for the 6.5V and a JSR-06 super regulator for the +-5V.
To sum it up - not much difference! Both sounded great.
If we get into bearly audible (or imagined) differences: Dac 2 - slightly sweeter and a bit more relaxed; Dac 1 - a bit brighter.
Ulf
Interesting.
Since +/-5 is only used by the opamps to generate +/-4, this appears to indicate the quality of 5v to the opamps is not that important.
I did some more digging and found the answer myself, thought I'd share my findings:
According to page 8 of 14 from the manual at Soekris Engineering, Inc. | How to buy the output impedance of the raw, unbuffered output is 625 Ohm. So anything with an input impedance upwards from 10k should do fine (1:20 ratio would give 12k5).
Currently running 1R series resistors on my v1 board (all I have at the moment) along with 499R Rc/51R Rp with 1200uF/0.01ESR. Definitely no more woolly bass here like there was with the 0R series and 16 cap mod.
I'm am curious how much difference between the 1R/0.1R series resistors make if one is interested in running a simulation for me. I've also replaced all the shift register bypass caps with 4.7uF X5R along with 47uF X5R vref ceramics. It appears Soren settled on 0.1R for production but I still see people running 0.01R as well.
I'm am curious how much difference between the 1R/0.1R series resistors make if one is interested in running a simulation for me. I've also replaced all the shift register bypass caps with 4.7uF X5R along with 47uF X5R vref ceramics. It appears Soren settled on 0.1R for production but I still see people running 0.01R as well.
Hello everybody.
I am also puzzled by this question. Was it possible for someone to find an answer?
I would be grateful for any hint.
Whats with the different resistor configurations? These are both -12 boards, was hoping they would be the same as I want to try a dual mono setup.
https://i.imgur.com/xswZY5th.jpg
https://i.imgur.com/xswZY5th.jpg
Cheers, thx. Nada to worry about. I had a prior reply all typed up including mentioning if it were different manufacturers but lost the post upon submission.
Dual mono works great, I had to use a pair of FTDI USB 3.3V TTL adaptors for each dam board but that was simple as I already use a PCB based USB header hub to integrate both Amanero and my existing serial converter to a single USB input anyway.
Sound quality seems better, but this could be more to do with implementing the new 1500uF 12mohm/vref 50R Rp resistor mods on the V2 boards. I do believe the nc400 modules perform better using a true balanced source than they do with an unbalanced to XLR cable as well. It's definitely a win.
There is no clicks or pops to speak of. The poweroff plop is totally gone with V2 boards (more like a tiny tiny barely audible flick), cheers to Soren for fixing that, even if it did require hardware to implement correctly. I have the dac modules connected straight to the amp and utilize the dam1021 volume control via serial adaptors.
To control both dac's in parallel I just run the dam1021.py python script via a shell wrapper that executes for each dac channel.
$ dam1021 -l 60
L:INFO:dam1021:Current volume level set to -60
R:INFO:dam1021:Current volume level set to -60
Will post pics later if anyone is interested.
Sound quality seems better, but this could be more to do with implementing the new 1500uF 12mohm/vref 50R Rp resistor mods on the V2 boards. I do believe the nc400 modules perform better using a true balanced source than they do with an unbalanced to XLR cable as well. It's definitely a win.
There is no clicks or pops to speak of. The poweroff plop is totally gone with V2 boards (more like a tiny tiny barely audible flick), cheers to Soren for fixing that, even if it did require hardware to implement correctly. I have the dac modules connected straight to the amp and utilize the dam1021 volume control via serial adaptors.
To control both dac's in parallel I just run the dam1021.py python script via a shell wrapper that executes for each dac channel.
$ dam1021 -l 60
L:INFO:dam1021:Current volume level set to -60
R:INFO:dam1021:Current volume level set to -60
Will post pics later if anyone is interested.
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