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

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J

jpoyarzun

Member
Joined 2013
neofeed said:
Hi,
From what Søren said : Rev 2 boards have the improved vref circuit and added parts to improve power on/off muting.

I think new batch comes preloaded with 0.99 firmware too.
Click to expand...

Hi, I have a question regarding this topic... I read earlier implementation experiences regarding this dac and almost everyone reported popping on bitrate change and another issues like powering on pops and so on.

I'm considering implementing this dac, but i need to know if everything is sorted out because my experience is not that great solutioning complex stuff.

Thanks a lot!
 
M

manniraj

Member
Joined 2012
jpoyarzun said:
Hi, I have a question regarding this topic... I read earlier implementation experiences regarding this dac and almost everyone reported popping on bitrate change and another issues like powering on pops and so on.

I'm considering implementing this dac, but i need to know if everything is sorted out because my experience is not that great solutioning complex stuff.

Thanks a lot!
Click to expand...

I have assembled the new revision Soekris DAC with Amanero and so far not experienced popping sound on any bitrate change and not during powering on or off as well. I had experienced some distortion initially during volume control changes on Foobar but that was I think because of not setting up the correct voltage on my PSU. Once the PSU output voltage was set to +/-12 the distortion disappeared and now I can adjust the volume on PC/Foobar while playback without any issues.
 
K

kumori

Member
Joined 2011
bmxmen said:
In the Rev 2 boards it is pasible to add 16 capacitors on the back of board like in preveus version? put capacitor in the same place like in rev 1 board? Have some on try this mod in the rev 2? And what capacitors will be the best for it?
Click to expand...

I would be interested as well.
Over at moredamfilters were several drawbacks and advantages of different cap arrangements and overall capacities shown. Could someone please summerize a "best practice" approach for the cap types and values used? (Beside leaving it as stock)

Apparently too much capacitance could sound boomy in some REV1 variants. Is this the case with REV2 as well?
 
M

MrSlim

Member
Joined 2009
Dimdim said:
It's very hard to make an apples-to-apples comparison since I'm pretty sure that there are no two DAM implementations that sound 100% the same.

My DAM implementation manages to sound different from a friend's implementation, even though we are using 99% same parts (same USB interface, same Vref mod, 95% same Salas BiB PS, same filter, etc).

Still, I hear that his implementation easily beat an Yggdrasil the other day. And he has a 0.05% board.
Click to expand...

Re your mention of your friend's DAM implementation beating the Yggdrasil, is there any anywhere we can read about the comparison/opinions?
I'd also love to see a description of your friend's implementation.
 
D

Dimdim

Member
Joined 2008
Here you go: DIY R-2R DAC (dam1021) : ?????????, ??? ??????... - Page 130

I'm afraid that it's in Greek, but Google translate should get (most of) the point accross. I can help if necessary.

My friend's Soekris is a 0.05% board, powered by a Salas BiB P/S at +/-12V, it has been modded with the original Vref mod (0.1R everywhere) but with with 4 x 470u polymer caps. It uses a DIYINHK XMOS receiver powered by a Salas Ref-D. It is essentially 99% the same as my implementation (documented in my blog).
 
oneoclock

oneoclock

Member
Joined 2010
Currently I have Soekris mod.1 (0.1 / 0/499) and 16 1000uF 0.007 ESR capacitors like Hifiduino.

I have very good jitter and very excellent sound and defined scene. But few bass dinamic, compared to other frequencies.

Possible Vref improvements with different modifications:

50 mOhm. Soekris mod.2 88uF 0.1 / 499 / 499.
10 mOhm. 1500uF (ESR 0012) 0.1 / 560 / (56 // 499)
4 mOhm 3x2700uF (ESR) 0.1 / 560 / (499//12)

attachment.php


You can choose several values of output impedance and look for combinations of several capacitors in parallel. With flat impedance to 500 Khz or more.
I make now 1500uF 0.01 ESR.
http://www.tme.eu/en/details/ulr1500_6.3/polymer-capacitors/x-con/ulr158m0jg1b/
attachment.php
 

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TNT

TNT

Member
Joined 2003
Paid Member
The "10 mOhm. 1500uF (ESR 0012) 0.1 / 560 / (56 // 499)" looks tempting.

It will be my next adventure. I run 1000uF 0/0/499, 1000uF at the clock and cheap 470pF transparent styroflex at output. If this would prove to be just a little more tighter bass and a tiiiiny little glance removed in upper midrange I will sit satisfied and it will be anything I can ask for.
 
K

koala887

Member
Joined 2012
Here is my mod for the rev.1 boards (0,01/100/499):
dsc02938ifbxw.jpg


As mentioned at moredamfilters.info, i changed the 1uF ceramics to 4,7uF, stacked 47uF on top of the 22uF and added 1500uF/12mR + 100uF/14mR polimers.
Here is the simulation with models from the murata/panasonic spicelib:
vref-imp81l33.jpg


When i play a 0dB sine sweep with the DAM, the pp-ripple at Vref is about 90uV up to 10kHz and then falls to 60uV at 96kHz, so the simulations seems to be right.:)

cheers
Daniel
 
J

jacczy

Member
Joined 2015
Hi to all,
finally, I made running dam1021-2 with RPI I2S, but I have a problem: DAC doesn’t play 44.1kHz sampled music. Other sampling rates play correctly. I thought maybe my RPI is wrong configured but I checked and with SABRE ES9018 every thing is ok.

Can anyone had something like that? What should I check?
firmware: FPGA rev. 0.99 20150816 and filters are standard 0.99

Regards
Jacek
 
oneoclock

oneoclock

Member
Joined 2010
kumori said:
@oneclock: i do not see why to change Rc to 560 ohms. Your table shows that Rp can be adjusted accordingly, even when staying at 499 Ohms. Are there any drawbacks?

Thanks
Florian
Click to expand...

I have at home 560 ohm resistors. That is the reason.
With Rc=499 is Rp=50: 1500uF (0.01 ESR) 0.1 / 499 / (499 // 50)

Another combination of 6 mOhm. UF 2700 (ESR 0012) Nichicon
PCG0J102MCL1GS Nichicon | 493-3086-1-ND | DigiKey

2x2700uF (0.012 ESR) 0.1 / 560 / (499 // 22)
or 2x2700uF (0.012 ESR) 0.1 / 499 / (499 // 20)
 
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