[richs]

I found a great dac to pair with my Sig 30 -- The dddac -- NOS, battery powered, with a USB to IC2 input.  This dac has been getting very good buzz, and I long wanted to give it a try.  Unfortunately it was available in a kit form that required skills well beyond my meager ability.  When Doede Doema recently began making "pre-assembled" kits available I jumped on it. 

I haven't used a soldering iron since I was a kid, but I was easily able to connect the 10 or so wires between the 3 circuit board and the outputs that make up the dac.  I opted for a version that has only USB input and 2 dac modules (Doede's design puts 12 dacs on a module, so my version is using 24 dacs.) There's an SPDIF input available for those not using a computer.  My total cost was $600 (plus another $70 to put in Jensen output caps recommended by Vinnie, matching those in the Sig 30.)

I'm not a wood worker but was able to easily mount the dac circuit boards in a maple box with a few brass bolts, glue and a drill.  I rigged up another box with the 12v battery and a couple of switches that let me toggle between powering the dac and charging, and powering the dac by battery or ac adapter (for non-critical listening).
As a bonus I built a switch into the dac box that allows me to switch between the dac and a second source without having to use a separate switching box.

As for the sound... Simply stunning.  My most recent comparisons are a Musical Fidelity A5, and X-DAC, X-10 and power supply combo (all V3).  Highs on female vocals are sweet and rounded with exceptional detail.  For example, I now hear an emotional tremor in Eva Cassidy's voice on "Imagine", that I never heard before.  Imaging is rock solid and detailed.  I hear different instruments placed across the soundstage much more then before.  The sound has an uncanny presence, and realism even at low volumes.  For $600 (and a little fun labor) this dac is a screaming bargain at 3x the price.

USB set up was a piece of cake.  My player, J River, recognized the dac immediately, and I was able to bypass k-mixer in the control panel.

Thanks to Vinnie for suggesting the capacitors and switches and fielding a bunch of questions about the dac.  As usual he went above and beyond providing great customer service.  Also, Doede is simply great to deal with.  He answered many, many very silly questions, and made assembling the dac completely painless.  His site is www.dddac.de.

BTW, I'm not an employee or friend of dddac.  Simply a thrilled customer.

For reference, I'm connecting the dac to the Sig 30 with a Virtual Dynamics Nite IC.  I'm feeding my Gallo Ref 3.1's with Virtual Dynamics Nite II cables.  My pricey power cables are now going up for sale.

[cfcjb]

Richs,
I'd be interested in hearing your opinion with regard the Signature 30 running your Gallos as I have the same set of speakers and have been leaning in the direction of the Sig 30/70. My Gallos are currently being powered by a Plinius 9200 integrated which by the way is a very smooth yet detailed amp. My CDP is a Resolution Audio Opus 21 which would allow me to run the Signature 70 monoblocks as well. I wouldn't be adverse to the Signature 70 either. Is there anyone out there that currently owns the Signature 70s with the Gallos? What I'm looking for is a blacker background and greater resolution without losing the smoothness and drive that the Plinius delivers. Also control of that shallow pan 10inch woofer is a concern.


Thanks in advance for your feedback.

Regards,

J.

[Jon L]

USB set up was a piece of cake.  My player, J River, recognized the dac immediately, and I was able to bypass k-mixer in the control panel.

Could you do some comparisons between USB/I2S input and spdif?

Also, we always love pictures

[richs]

J -
The Sig 30 is doing a fine job running the Gallos. But.... I have a small listening room (14x14 with a 7 ft ceiling).  I also listen at a fairly low level (typically 75-80 db).  With that I have the Sig 30's attenuator set at 3/4 full.  I control the rest of the volume with my computer.  If I had a bigger room or listened louder, the pairing might be a bit of a stretch.  Also, my dac puts out about 2 volts.  Your dac output will also affect the pairing.  I really can't comment about the Sig 70's.  I'm sure they would sound better.  I don't know how much.  I had a Musical Fidelity A308 for quite a while, and the Sig 30 sounds better than that in every way.

John -

Unfortunately I can't comment on the spdif comparison.  Since a computer is my only source now, I didn't spring for the spdif module.  I do wonder how much of the dddac's performance is driven by battery power vs. IC2 vs. the 24 dac configuation.  But it's an academic interest that I have no way to test.

I will try to post few pictures tomorrow.

Rich

[TomS]

Rich,

Great post.  Just wondering if you know if this USB to I2S is similar to Empirical Audio's implementation (Off-Ramp I2S)?

Tom

[richs]

Tom,

I don't really know.  I recall reading in a post somewhere that the dddac I2S implementation was different from Empirical's, but I'm not technical enough to know if that's true, or if one is better.  Frankly, I never really knew there were different ways of implementing it that would have meaningful impact on sound.

Rich

[brj]

Be aware that for the DIY inclined, the USB->I2S board from DDDAC is a separate unit that could be added to an existing DAC that already takes I2S.

In addition, one could use USB->I2S portion of the Scott Nixon Tube DAC kit for the same purpose.

I thought I knew of a third such option, but I can't find it at the moment...

[JDUBS]

Be aware that for the DIY inclined, the USB->I2S board from DDDAC is a separate unit that could be added to an existing DAC that already takes I2S.

This is the part that I think is intriguing.  Question I have is...what are some of the more popular DACs out there that can take an I2S signal? 

[Gordy]

The Perpetual Tech. P3a has I2S inputs.

[Vinnie R.]

Hi richs,

Thanks for posting and I'm happy to hear that your Sig 30 + Gallo pairing is working very well for you.  I remember your first post: http://www.audiocircle.com/index.php?topic=30046.msg266997#msg266997
and based on what you posted for your room size and listening levels, I knew you would love the Sig 30 + Gallo comob!     Also, thanks for recommending the dddac to us.  It is hard to beat the musicality of a good NOS, SLA battery powered dac!

Also, my dac puts out about 2 volts.  Your dac output will also affect the pairing.

Do you happen to know if this is 2 Vpp (volts peak-to-peak) or 2 Vrms (volts RMS)?

My CDP is a Resolution Audio Opus 21 which would allow me to run the Signature 70 monoblocks as well. I wouldn't be adverse to the Signature 70 either...

...What I'm looking for is a blacker background and greater resolution without losing the smoothness and drive that the Plinius delivers. Also control of that shallow pan 10inch woofer is a concern.

Hi cfcjb,

If you are in a larger room and play at louder levels, the Sig 70 is the better choice.  Having twice the output current with the Sig 70s definitely gives better dynamics, more bass attack, and control at louder levels.  Both the Sig 30 and the Sig 70s offer a full, warm tone with a detailed and extended top end.  A very black background and smoothness are both there in spades with these amps! 

Best regards,

Vinnie

[dddac]

Hi Rich,

thank you for your positive feedback on my design and on the perceived support. Always good to hear this 

To some other questions:

On my Web Site I describe the difference between spdif and usb. The USB is more detailed and have a more open soundstage as the spdif. Specially low level detail, like the "soundtexture" of a voice of instrument is improved much. Even as I am using a good transport the USB wins. No longlisteing sesions, just play the same track again and you know what it is all about  ....  At current, I have lossless ripped all my CD collection and listen trhough a Notebook, I only use in my listening room as media server (so it is always there and connected when I need it....) Must say, it is easier to skimm through some music as going through the rack with all CD's and walking back and forward to the player 

The output is slightly below 2 Volt RMS at 0dB signal on the CD with output impedance of aprox 100 Ohm for the 24 dac as Rich has ....

Best regards,

doede

[ted_b]

Doede,
Sounds like a great DAC, especially for the money.  Two questions:
1)  for non-DIY'ers like me will you or anyone produce a fully built DAC for a price?
2)  for Squeezebox implementations, would it make any sense to design a sp/dif to USB capability or is the "damage" already done prior to the spdif, making a conversion moot?

[richs]

Ted,

You might want to email Doede directly with any questions. Contact info is on his web site (www.dddac.de.).

For SB implementation you would want to forgo the USB entirely and use the spdif module. Then you go from the spdif out of the SB to the spdif in of the dddac.  The nice thing about the USB implementation is that since it is I2S it bypasses spdif entirely, thus avoiding some jitter issues.

I don't know if Doede would build a complete unit.  But I'm not technical at all, and I was easily able to solder the 10 wires and put it a square wooden box with no problem.  If you go this route, I'd be happy to email you some pictures with instructions to help out.

Rich