4 Decks is absolutely stable. 8 decks can be instable,(fix is on the way) but it never that strong as like what you described. Therefore we need to take this as an individual issue. Please send me an (normal) email and we will take it from there. There are a couple of things we need to go through to diagnose the Problem
thanks,
doede
Had the same problem here with 4 decks. Doede´s advice was to increase the i2s voltage on the "motherboard". Problem solved with a +5v belleson!
apoo
I suggest that the difference you hear is likely due to something other than the DAC noise floor.
Hey
i'm fairly new to the whole diy audio community.
I've heard a great deal about running circuits on a battery supply. dvb-projekt uses A123 LiFePo4 cells in his newest red barron design (altough not for the whole circuit i think).
Is it possible to run the WaveIO board and/or the dddac on batteries? What do you expect from it? Did anybody tried this?
i'm fairly new to the whole diy audio community.
I've heard a great deal about running circuits on a battery supply. dvb-projekt uses A123 LiFePo4 cells in his newest red barron design (altough not for the whole circuit i think).
Is it possible to run the WaveIO board and/or the dddac on batteries? What do you expect from it? Did anybody tried this?
About battery for the dac part, you can check Doede's site:
DDDAC 1794 NOS DAC - Non Oversampling DAC with PCM1794 - no digital filter - modular design DIY DAC for high resolution audio 192/24 192kHz 24bit
About waveIo, I don't know. You can search on the waveIo thread.
DDDAC 1794 NOS DAC - Non Oversampling DAC with PCM1794 - no digital filter - modular design DIY DAC for high resolution audio 192/24 192kHz 24bit
About waveIo, I don't know. You can search on the waveIo thread.
It is quantization noise. Normally you do not hear this, except when you use digital volume control (so the dac is always at full power to the end amplifier, or using a very sensitive system. Anyway, I just did some experiments with some 8-decks towers and found a very nice fix for this. Have a look at the picture. Basically you are decoupling the internal HF spikes from the A and B DAC inside the chip. By adding a capacitor at the top of the tower between A-pos and B-pos and one between A-neg and B-neg, things improve dramatically. Noise floor drops 10dB. D2 reduces to -60dB and d3 to -70dB. No surprise the sound gets a bit cleaner as well. Value is not critical. To have a roll off outside the audio band, use 2 – 5nF per deck . So 4 decks you could take 10nF, 15nF or 22nF, for 8 Decks the double. Just give it a try
Attachments
sure... 5nF would be like 55 kHz, 2nF would be 140kHz ...
this is all linear in relation. 10nF would do 22kHz 1nF 280kHz
this is all -3dB Points -1dB Point is one octave lower... so 10nF would be a bit too much I think
Cinemag transformer model
Hello All, I've joined the club and have been thoroughly enjoying Doede's DAC!
Just Breadboarded for now, but a case is in the works.
I am thinking of adding the Cinemag transformers. Is this the most appropriate model?
CMLI-15/15B2
Also planning on trying an Interstage Coupled 6AH4 Line Stage with no cap at the DAC ouput.
Thank you for the wonderful DAC Doede!!!
Hello All, I've joined the club and have been thoroughly enjoying Doede's DAC!
Just Breadboarded for now, but a case is in the works.
I am thinking of adding the Cinemag transformers. Is this the most appropriate model?
CMLI-15/15B2
Also planning on trying an Interstage Coupled 6AH4 Line Stage with no cap at the DAC ouput.
Thank you for the wonderful DAC Doede!!!
Attachments
please download the schematics from my website or post on page one and see for yourself it does split very nicely into left and right channel. both R and L are completely in sync now other than simpler solutions where I2S is sequentially giving out L and R word...
Battery Power
Yes, I run both DAC and WaveIO from batteries, the DAV from a 11v 1200mAh LiPo and the WaveIO from a iPhone / iPad battery booster at 5v, both work fine and the overall sound is very clean & dynamic.
Regards
Howard
Yes, I run both DAC and WaveIO from batteries, the DAV from a 11v 1200mAh LiPo and the WaveIO from a iPhone / iPad battery booster at 5v, both work fine and the overall sound is very clean & dynamic.
Regards
Howard
After a discussion with David at Cinemag he recommended the /15B as he couldn't really see any benefit for the /15B2 in this application. Mine are on order and should be here in a few weeks time.
Nice tweak Doede, I've used 22nF on my 4 deck DDDAC and it does sound even better. I can't confirm with any measurements as I haven't got the equipment to do so.
Noise problem finally "solved"
Hi,
I finally managed to "solve" my problem with digital noise at the DDDAC output.
The problem was that I was going for a kind of unconventional build of the stack with two decks above and two below the motherboard. In my mind, this was supposed to be better for summing and distributing the signals since the wires were shorter which meant a tiny bit lower inductances. However, I ended up having very strong digital noise at the outputs. This phenomenon looked like rectangular steps superimposed on top of the main signal. Noise was mostly present when the amplitude of the signal was low, still it was very audible at the output. The situation was worse with SPDIF board (the board designed by Doede for DDDAC 1543) than with WaveIO. The noise became also much stronger when the BCK signal was touched by any kind of measuring instrument (multimeter, oscilloscope probe). I tried many different things. Some of the modifications reduced the noise but it was never really removed. At some point I found out that the stack works perfectly with 3 decks and the removed deck worked well by itself as well. When I ran out of ideas and decided that I remove the bottom deck and run the converter with only 3decks, I had an idea to try to connect the deck which was removed to the top of the stack. I was very surprised when turning the converter on, the noise was completely gone! To say that I solved the problem may be a very strong claim since I don't know what was the problem in the first place. For now I run my setup with 3 decks above and one below the motherboard and all is well.
I have also something to say about the capacitors between the A and B channel. I tried this as one of the solutions to my problem. It didn’t really work, but when the problem was finally solved the difference with and without the capacitors was very clear. Apart of the difference in sound, where before were quantisation steps in the signal when measured; now everything is very smooth. In addition to that, before when there was no signal played, the noise floor was +/- 2 quantisation steps wide. After adding the capacitors, the steps are not there anymore and the noise is closer to zero.
I hope that some will find this long story interesting and that someone may have an idea what was really wrong in my original stack. Thanks to Doede for email support, some of the ideas were very inspiring even though the final solution was very unconventional.
-----------------------------
Martin
Hi,
I finally managed to "solve" my problem with digital noise at the DDDAC output.
The problem was that I was going for a kind of unconventional build of the stack with two decks above and two below the motherboard. In my mind, this was supposed to be better for summing and distributing the signals since the wires were shorter which meant a tiny bit lower inductances. However, I ended up having very strong digital noise at the outputs. This phenomenon looked like rectangular steps superimposed on top of the main signal. Noise was mostly present when the amplitude of the signal was low, still it was very audible at the output. The situation was worse with SPDIF board (the board designed by Doede for DDDAC 1543) than with WaveIO. The noise became also much stronger when the BCK signal was touched by any kind of measuring instrument (multimeter, oscilloscope probe). I tried many different things. Some of the modifications reduced the noise but it was never really removed. At some point I found out that the stack works perfectly with 3 decks and the removed deck worked well by itself as well. When I ran out of ideas and decided that I remove the bottom deck and run the converter with only 3decks, I had an idea to try to connect the deck which was removed to the top of the stack. I was very surprised when turning the converter on, the noise was completely gone! To say that I solved the problem may be a very strong claim since I don't know what was the problem in the first place. For now I run my setup with 3 decks above and one below the motherboard and all is well.
I have also something to say about the capacitors between the A and B channel. I tried this as one of the solutions to my problem. It didn’t really work, but when the problem was finally solved the difference with and without the capacitors was very clear. Apart of the difference in sound, where before were quantisation steps in the signal when measured; now everything is very smooth. In addition to that, before when there was no signal played, the noise floor was +/- 2 quantisation steps wide. After adding the capacitors, the steps are not there anymore and the noise is closer to zero.
I hope that some will find this long story interesting and that someone may have an idea what was really wrong in my original stack. Thanks to Doede for email support, some of the ideas were very inspiring even though the final solution was very unconventional.
-----------------------------
Martin
I start the building of this DAC with 3 PSU (the 3rd one is for the WaveIO card) in a aspearated chassis and specific PS transformers.
I wll use 4 DAC modules with the 2 Sowther, so I have to adjust the Ra and Rb values to 68R.
I have read int he post #253 from my friend Almeg69 that he has used the 2W Audionote Non Magnetic resistors.
Do we have any feedback regarding the improvement these resistors bring ?
Thanks
I wll use 4 DAC modules with the 2 Sowther, so I have to adjust the Ra and Rb values to 68R.
I have read int he post #253 from my friend Almeg69 that he has used the 2W Audionote Non Magnetic resistors.
Do we have any feedback regarding the improvement these resistors bring ?
Thanks
Hi Martin,
Always interesting to share these kind of experience, this is what keeps mankind evolving.
However I am not sure as to what the problem with your setup was. Could it be a bad soldering joint that now is solved by moving the dac board?
Regards,