Soekris R-2R DAC Exploration: User opinions, impressions and DIY experience

raghupb

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Hey Folks,

A couple of months ago I was suggested by an FM to explore DACs from Soekris.
I had brushed it aside because of the DIY factor. But did some reading about them nonetheless.
So this is a thread starter post for my exploration into a potential DIY effort.
If it happens, I will open a dedicated thread in the DIY sub-forum.
For now will keep it in the DAC sub-forum.

Interesting tech and implementation as per designer's literature (it is sparse though).
They do have finished commercial products, DAC-1101, DAC-1321, DAC-1421, DAC-1541.
The DIY and OEM modules are more interesting and frankly more affordable, IMO.
DAM-1021 has been a very popular choice among DIYers.
AFAIK, locally in Bangalore @manniraj & @jai1611 use these DACs built out of 1021s.
Also @MaSh is exploring to procure a 1021 too. On HFV it seems Bangalore is a Soekris users hub :)

Now they also have 3 OEM models:
DAM-1121: the basic model pcb (SPDIF/I2S input, SE output)
DAM-1921: advanced model with more input choices and SE output
DAM-1942: advanced model with balanced output

My curiosity is piqued by the 1121. I am thinking of this using this module as a simple DAC.
Digital SPDIF input, on RCA or BNC, BNC preferred as Allo Digione has a spare BNC out.
Analog RCA out, which is at 1.4V unbuffered. I think the preamps at home can work with this line voltage.
If my understanding is correct, this module needs a transformer and 2 or 3 regulators
Vcc5D for the digital side
Vcc5A and Vee5A for analog side
There are recommendations for transformers too in public domain.
Have to explore what's available locally to keep things simple.

@jai1611 also pointed me to regulator modules that can be purchased/sourced from US.
As for procurement of these DAMs, the easiest option seems to be procure in US and get it hand carried.
But the choices are less at US reseller due to stocking issues.
EU store/reseller has wider choice, but in my case I have to import it.
This makes it a non-starter cost wise.

Anyways, I'm looking for opinions and impressions from users of this DAC (model doesn't matter for now).
Will be hitting up of the DIYers to know more about build experience and challenges.
So I thought of putting it out here for wider input and for folks who might be interested.

Please chime in if you have any relevant information about Soekris products.
Comparisons with other products are OK, if applicable, but let's stick to the DIY angle using Soekris.

Cheers,
Raghu
 
Following!
Even I was thinking of getting Soekris DAC board- as you mentioned importing one is a costly proposition. But in September I saw a guy selling 4 boards of Soekris DACs on diyaudio.com for USD 300/- each. If somebody is coming down from US they can hand carry it.

PS: But in my case I splurged it all on a mechanical watch :p - and the same acquaintance will hand carry it for me if it gets delivered in time.
 
I'd suggest a 1021. Power supply is simple +/- 12V. For which a linear supply can be easily assembled.
It also has 2 Spdif inputs and 2 i2s inputs. Can do balanced or SE out.

Sounds great.
 
Finally landed a loner unit of Soekris DAM-1021
Pretty good DAC. It actually accentuates the "speaker disappearing" act
AKSA does the heavy lifting to provide the depth of stage, but this DAC pushes the last mile.

It makes me want to really consider doing a build.
Let's see how it goes.

Cheers,
Raghu
 
Finally landed a loner unit of Soekris DAM-1021
Pretty good DAC. It actually accentuates the "speaker disappearing" act
AKSA does the heavy lifting to provide the depth of stage, but this DAC pushes the last mile.

It makes me want to really consider doing a build.
Let's see how it goes.

Cheers,
Raghu

Can you show how this DAC looks and some specs?
 
My intent is very specific
Allo Digione has RCA and BNC out. I confirmed that these are independently buffered.
RCA goes to Parasound Preamp --> Poweramp
BNC goes to Soekris --> Lyrita pre --> AKSA
(see sig)

I get to separate the chain at the source/streamer.
More power to me as I can still operate it from laptop (headless)

The big constraint for me is, it has to be housed in a chassis 10" or less

Cheers,
Raghu
 
Can you show how this DAC looks and some specs?
http://www.soekris.dk/dam1021.html (the module)
http://www.soekris.dk/download.html (manuals)

Various DIY forums have dedicated threads on how to build.
This is a good starter page.

Cheers,
Raghu
 
I got to play around with a DAM1021 (1% tolerance) which came for a minor service. It did not have the USB module.
Used coax from digione signature.
Sounded quite good. Was my 1st experince with a R2R.
Quite a different character than a Sigma Delta based DAC whuch I use.
 
I got to play around with a DAM1021 (1% tolerance) which came for a minor service. It did not have the USB module.
Used coax from digione signature.
Sounded quite good. Was my 1st experince with a R2R.
Quite a different character than a Sigma Delta based DAC whuch I use.
I've assembled 2 of them, one for me and one for someone else. Happy to provide any input. It's a lovely dac.
Any recommendations on the pulse transformer to be used for the digital RCA/Coax?
Cheers,
Raghu
 
Availability wise it seems DAM1021 can be procured in US and hand carried.
Rev7 seems to be in stock. Makes sense for me, since I don't want to import and pay hefty taxes/duty.

Has anyone tried using a decent transformer 230 --> 7/8V directly powering the 1021 as suggested by the designer?
Specifically on the later revisions of the module. Any technical gotchas? SQ gremlins?

Most of what I read on diyaudio forum revolving around PSU is for earlier revs of the board (rev 1-3 mostly).
The popular PSU implementations are:
Salas Bib/Ultra-Bib
DIYINHK
NewClassD UWB

Cheers,
Raghu
 
Just read about this on Soekris site. The manual is outdated.
Rev7 boards just take in +/- 8V to +/- 15V as input.
So I guess a transformer and a pair of good PSU boards are needed.
Sorry for the confusion.

Cheers,
Raghu
 
Couple of guys from Delhi & Bangalore might be wanting to sell their Soekris 1021. If anyone’s interested..
 
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