[dburna]

I have had (several) NOS DACs -- like 'em.  I am currently using a 1704-based DAC -- also a good listen.  But I am intrigued by this DAC as a cost-effective (soon-to-be?) DSD-supporting NOS R2R alternative (for not a lot of coin).

Question: what would it take to build one of these DACs?  I'll start by venturing a guess:

(1) Soekris DAC board
(1) power supply, preferably linear
(1) I/O interface board, ideally supporting at least S/PDIF and USB -- what would mate well with this implementation? 
(1) Chassis
Various switches (depending on number of inputs), I/O connectors, wire, LED(s)

I am thinking that the power supply and I/O board would provide the greatest influence (and range of choices) to the implementation.  Did I miss anything?

Thanks,  -dB

[JDUBS]

I have 4 on order. Going to go active with 8 ncore and tympani's......

How are you going to accomplish this, specifically source->4x of these DACs?

-Jim

[randytsuch]

I have had (several) NOS DACs -- like 'em.  I am currently using a 1704-based DAC -- also a good listen.  But I am intrigued by this DAC as a cost-effective (soon-to-be?) DSD-supporting NOS R2R alternative (for not a lot of coin).

Question: what would it take to build one of these DACs?  I'll start by venturing a guess:

(1) Soekris DAC board
(1) power supply, preferably linear
(1) I/O interface board, ideally supporting at least S/PDIF and USB -- what would mate well with this implementation? 
(1) Chassis
Various switches (depending on number of inputs), I/O connectors, wire, LED(s)

I am thinking that the power supply and I/O board would provide the greatest influence (and range of choices) to the implementation.  Did I miss anything?

Thanks,  -dB

For the power supply, you need +/-12VDC.  The DAC converts this to the voltages it needs, and is supposed to have good on board regulation.  One guy compared batteries to a SNPS and didn't see much difference, but he wasn't specific about what he heard either.  But I plan to make a simple linear, and may even try a Salas shunt (because I have the boards already).

For IO, I am going to just use a Amanero USB to I2S board.   You need to connect three I2S lines from there to the DAC, along with ground and power for the isolator circuit on the DAC.  I will run the I2S lines twisted pair with grounds. 
For SPDIF, I think guys are planning to use transformers, but I'm not going to use.

You need either a POT or microcontroller with a serial port to control volume.  The pot is used to generate a voltage that the DAC reads to decide the volume, so only a mono POT is required.  Designer is recommending conductive plastic type POT.  If you don't want to control volume, I think you can just not do anything, and it will output at 0db gain, which should be fine.  I will connect a POT and see how it goes.

Randy

[JohnR]

Hi Randy, how's your build going?

[Rocket]

Hi,

How do you guys know how to build these electronic projects?  Are you self taught? or have you done some courses?

Regards Rod

[poseidonsvoice]

Randy and cab,

I'll be interested in what you guys think of this dac. I am more than pleased with my Aries/Vega and I have vowed to not build anything else digital as the technology moves very fast. You end up taking a bath in the used market as these "small kit" manufacturers don't do updates on your said design often enough or from an affordable standpoint. I guess that's the risk you take! But it's fun though, no doubt!

Good luck and let us know. Part of me wants to build an 8 channel dac for theater!

Best,
Anand.

[orientalexpress]

any news?

[randytsuch]

Hey guys
So like many of my projects, this one was set aside for a while 

But its back on my bench.

I connected a couple of walwarts so I could power it up, and connected the serial port to a 232 converter I bought for this.

Using instructions from dim dim's and hifiduino's blogs, I updated the firmware to 0.99 (latest as of now) and also loaded in a new filter.  There has been a lot of effort by different people on the filter front, and appears to make a big difference in the sound.

I also removed the opamps on the output, going to use the "raw" single ended output.

So, I hope to connect my Amanero usb to i2s converter to it soon, and hopefully make some music.

Future plans are to replace some of the regulators with lifepo4 battery power.  Since I don't have opamps, the cards has 4 voltages, 1.2V, 3.3V and +/-4V (for the ladder).  The 1.2V is for the FPGA, and 3.3 is for the rest of the logic.

BTW, reports I've read on modified Soekris Dacs are very promising.  And I guess the newer ones have a lot of these mods already installed, but the original ones appear to need mods to sound good.

Randy

[randytsuch]

Monday morning update.

I have music 
Didn't work the first time I tried, no lock

So, after checking connections many times, I reloaded the FPGA. 
After that, it worked no problem.  Locks quickly, and sounds pretty good considering I'm powering with walwarts.

I'm now setting up to battery power the ladder section of this dac.  The power supply to the ladder was found wanting in the early version like I have, and supplying battery power should help a lot.

Randy

[JohnR]

Thank you Randy. Please keep updating

[randytsuch]

Thank you Randy. Please keep updating

So I created a couple blog pages.  One to get you started
http://randytsuch-audio.blogspot.com/2015/11/soekris-r2r-dam-dac.html

And here is the page with the mods I've been making to the dac
http://randytsuch-audio.blogspot.com/2015/11/soekris-r2r-dam-dac-modding.html

A stock dac, with a very simple power supply (I was using walwarts I had laying around) sounded pretty good, actually very good for the price.

But after making these mods to it, it sounds really good now.  Very detailed with a very low noise floor.  I hear background noise in some recordings that I had not noticed before.

The mods are not that hard to do, if you've worked on surface mount boards before.  The right tools are important, as with most things.

My mods page is not quite up to date, but it's getting pretty close. 

I have a few more mods I want to make, but I could stop now, and be quite happy with this dac.

Randy

[wushuliu]

Just ordered the rev3 board. I plan on making the fewest mods needed to get good sound. I'll use the I2S outs from my awesome F-1 converter for input. I think I can use the 3.3v from the F-1 to the dac, thereby not needing a separate PS. For main power I am trying out an inexpensive SOLA power supply with +/- 12v, 5v, and 5mv ripple:

[richidoo]

Hi,

How do you guys know how to build these electronic projects?  Are you self taught? or have you done some courses?

Regards Rod

Many of the better DIY projects have pretty good documentation, so it is fairly straightforward to provide power supply, data input, analog output to the project board. This one has much of those resources already designed on the board. Just supply AC and wire up your i/o jacks. I think this one needs an I2S source, like Amenero USB board, equally simple to execute.

It seems difficult at first, but you ask the designer and other forum members for assistance and before you know it you finished and learned something to apply toward the next project. They are intended to be buildable by amateurs.

[wushuliu]

Just fired up my Soekris DAC. It is f*cking great . I took a minimalist approach:

Soekris DAC .5 resistors Rev 3 ($195)
SOLA Power AC/DC 12v Linear Power Supply (<5mv ripple, $30 ebay)
Singxer F-1 USB/SPDIF/I2S Converter ($180)

The Rev 3 boards incorporate mods that evidently elevate the Soekris well beyond the initial version. So the only mod I have done is remove the output opamps. Two of the opamps are glued tight with pads underneath so they were kind of a pain to remove, so approach with care. DC supply is what's recommended and people are using all kinds of ways to power the board. I chose to keep it simple to start with. The SOLA is compact, well made, easy wire up and has great specs. Highly recommend used linear supplies like these on ebay, they are inexpensive.

I've raved about the Singxer F-1 in C&C. Just get one. You won't regret it. The plus side of the Singxer is you can wire the I2S connection straight to the Soekris, including power, so you don't need to worry about buying/building a usb/coax/toslink input and figuring out how to power it, etc etc. Easy peasy.

How does it sound? Frickin' excellent. I can hear the appeal for R2R/ladder DACs. This does not sound like anything remotely budget. The realism, dynamics, man, wow. Kind of like live performance. Glare-free, low noise floor. I mean, it makes you shake your head at amazement in how much information is in redbook material. If you told me before knowing about this dac that what I was hearing was hi-res I wouldn't doubt it for a second. Unfortunately, I can't say just how much is due to the Singxer, which on its own, will get you part way there with any (coaxial) DAC. Plus I have the proto-LanRover ICron usb/ethernet extender helping out as well. So there's a lot of stuff in the chain. But in the past month I have demo'd: Micromega MyDAC, Peachtree DaciT, Ifi DSD Micro/IDAC 2. The Soekris is something else altogether.

I am using the Soekris stock filter, which is considered okay (the upper treble is just oh so slightly hot), but there are superior custom filters available from moreDAMfilters/diyaudio, so that will be my next step.

[Folsom]

Good to know you like it.

Twisting wires that are gounds with signals will help. Consider the outputs are radiating a lot more without twisting, near the sensitive stuff.

A metal box will may give a noticeable sound improvement too.

Are you talking about input filters?

[richidoo]

Just fired up my Soekris DAC. It is f*cking great .

Thanks, good info there. Exciting project!

[poseidonsvoice]

Looks great wushuliu! At least it was an inexpensive build with great sound 

That's always a plus 

Anand.

[wushuliu]

Good to know you like it.

Twisting wires that are gounds with signals will help. Consider the outputs are radiating a lot more without twisting, near the sensitive stuff.

A metal box will may give a noticeable sound improvement too.

Are you talking about input filters?

Yes i'll do the wire twisting for ps and sig later. I want to upgrade the wiring before i do all that. Wanted to get it up and running first.

I meant the dac filters e.g. minimum phase linear etc. You can add custom ones that are much better. Makes you wonder about what comes with retail dacs.

[wushuliu]

Looks great wushuliu! At least it was an inexpensive build with great sound 

That's always a plus 

Anand.

Thanks. Got back in the hobby at the right time!