Buffalo IIISE and Unbalancer DAC/Linestage

[kvardas]

Built a delta-sigma DAC/Line Stage as shown below:



The DAC module is the "Buffalo IIISE-DAC", which is based on the ESS Sabre32 Reference (ES9018) DAC chip and accepts direct DSD, I2S and S/PDIF inputs supporting up to 32-bit/192kHz.

A liner power supply is used to feed a low noise regulator (SuperTeddyReg) that provides the 5.25 volts for the DAC module.

The volume control is done in the digital domain of the Buffalo IIISE via a linear potentiometer.

The output stage is a tube line stage called the "Unbalancer", which was designed by John Broskie:



All capacitors and resistors were upgraded. A separate tube rectifier power supply (Janus) is used to provide the B+ voltage and DC heater voltage for the line stage.

Duelund PIO 1uf / 630VDC, CAST-PIO-Cu Coupling Capacitors (I like these) are used:



DSD and PCM signals from a modified Denon 1920 multi-player are extracted from the player by tapping directly to the chip pins as shown and noted below:



Per the following pin connections:

DVD-1920 DSD -> Buffalo
BCK (Pin 37) -> DCK
DSD1 (Pin 38) -> D1
DSD2 (Pin 39) -> D2
G (Pad CS52) -> G

DVD-1920 PCM -> Buffalo
PBCK (Pin 50) -> DCK
PLRCK (Pin 51) -> D1
PDATA1 (Pin 46) -> D2
G (Pad CS52) -> G

And distributed to the DAC via an RJ45 cable:




I think it sounds great.

Next step is to build or buy a music server to play downloaded HD recordings into the DAC.

Cheers

Kris

[Hdale85]

Awesome! I've been wanting to build a Buffalo since the original announcement, I was part of the crowd that begged them to make it lol. I'm still considering using it in my car project though possibly.

[---k---]

Very nice.
I don't know anything about building DACs or amps or anything. It is something that I think about from time to time, but just haven't gotten around to it.
Is this a kit, or bits of different kits, or original designs? Got any links?

[JonMarsh]

Kool stuff, Chris! The tapping in to the Denon reminds me of what I had to do with the first Audiopraise board, installing it for extracting/converting the DSD stream to high res PCM.

You picked a good coupling cap! :T

[kvardas]

Very nice.
I don't know anything about building DACs or amps or anything. It is something that I think about from time to time, but just haven't gotten around to it.
Is this a kit, or bits of different kits, or original designs? Got any links?

It is a combination of multiple modules:

The DAC module can be found here:

http://www.twistedpearaudio.com/digital/buffalose.aspx

You can download the manual for it off their site.

The linear power supply was from parts-express. I used a small module with an adjustable output, which I set for about 14 volts.

I used a superteddy reg, which I ordered for an input voltage of 13v and an output voltage of 5.25v under load (this low noise reg needs a minimum 6v headroom:

http://www.teddypardo.com/diy/superteddyreg.html

The unbalancer tube module coverts the balanced output of the DAC module to single ended:

http://glass-ware.stores.yahoo.net/unbalacer.html

The manual can be found here:

http://tubecad.com/2011/11/25/Unbalancer%209-pin.pdf

I upgraded all of the capacitors and resistors. In particular resistors 1 and 2 should be set to 50R. I used a nice neohm wirewound resistor.

I also used an separate B+ power supply module with upgraded bypass caps:

http://glass-ware.stores.yahoo.net/jashrekit.html

The manual can be found here:

http://glass-ware.com/User_Guides/Janus%20Rev%20A.pdf

The nice duelund coupling caps are on sale and can be found here:

http://www.partsconnexion.com/DUELUND-71506.html

I used a two-position power switch to power the 12.6 v transformer for the heaters and a separate transformer for the B+ voltage and rectifier tube voltage:

http://www.partsconnexion.com/DUELUND-71506.html

The volume control is done in the digital domain of the DAC. I used a Chinese ebay remote control pot for the volume control. You likely will need to replace the motorized pot with a linear 10k pot.

You'll need three transformers:

A approx 15v toroid for the DAC.
A 12.6 EI transformer for the heater voltage. I got mine from RadioShack and painted it black.

http://www.radioshack.com/product/index.jsp?productId=2102702&filterName=Type&filterValue=Transformers

A high voltage EI transformer:

http://www.alliedelec.com/search/productdetail.aspx?SKU=70009005

You could go a simpler route as use the solid state power supply on the unbalancer if you wish and go with a lower voltage transformer.

Those are the main components. I and a friend who did the soiled ring and helped with the design put together a detailed schematic. I could scan this on a flatbed scanner and send to you.

You could go with one of the solid state output modules from twistedpairaudio audio if you did not want to trouble yourself with a tune output stage.

Regards

Kris

[---k---]

Wow. Thanks for all the links. Lots of info there. Skimming the DAC manual now.