SOTAPRAT DAC updates

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audioengr

SOTAPRAT DAC updates
« on: 23 Jun 2019, 05:12 pm »
I'm designing an affordable DAC, but with the great SQ that Empirical Audio is known for.  I can do this because I have discovered some new parts that allow me to finally design one without using multiple expensive discrete Hynes-type regulators that must be configured and tuned.  The DAC will contain the new Crystek low-jitter master clocks.

Features that I have designed in so far:

1) USB or Ethernet input interface (Roon compatible) - purchaser chooses one
2) SPDIF input (75 ohm BNC) with my world-class Synchro-Mesh reclocker in series internally
3) RCA analog outputs only, no XLR balanced
4) Front panel power button
5) Front panel input select button
6) LEDs for power, data error and DSD on front panel
7) DSD capability for both USB and Ethernet
8] Output muting when no signal
9) IEC inlet - automatic international power compatible
10) Ground-lift switch on back-panel
11) Uses Analog Devices AD1955 D/A with customized digital filter programming
11) Pricepoint - $3K for USB version, $3.5K for Ethernet version
12) Compact silver aluminum chassis with milled aluminum front panel
13) US-type AC power cord included?

All one needs is a computer or a server and a USB or Ethernet cable.

Did I miss anything?
« Last Edit: 25 Aug 2019, 12:18 am by audioengr »

mresseguie

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Re: Features for my new DAC?
« Reply #1 on: 24 Jun 2019, 06:10 am »
Question:

Why did you choose the AD1955 chip?

Michael

rollo

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Re: Features for my new DAC?
« Reply #2 on: 24 Jun 2019, 02:22 pm »
  Well feature wise sounds like a winner. The only way to tell is try one.


charles

audioengr

Re: Features for my new DAC?
« Reply #3 on: 24 Jun 2019, 04:26 pm »
Question:

Why did you choose the AD1955 chip?

Michael

Because I use a predecessor in my current DAC and I know how to deliver power to it and tune the digital filter to make it sound great.  Uses the same digital filter.  These even beat NOS DACs. I used to make a NOS DAC.

I've auditioned AKM D/A chips and Sabre D/A chips.  I prefer the liveness of the Analog D/A chips.

Steve N.

audioengr

Re: Features for my new DAC?
« Reply #4 on: 24 Jun 2019, 04:28 pm »
  Well feature wise sounds like a winner. The only way to tell is try one.


charles

I may send one around on a trial to those that sign-up.  I'm a couple of months away from having the first one.

Is the price okay for the feature-set?  I have priced this one so I can sell through dealers to hit a wider audience and get higher volume.

Steve N.

rollo

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Re: Features for my new DAC?
« Reply #5 on: 24 Jun 2019, 04:41 pm »
  Price point is just fine for dealers. Keep up the good work.

charles

ketcham

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Re: Features for my new DAC?
« Reply #6 on: 24 Jun 2019, 09:43 pm »
$3500 is retail or wholesale?

richidoo

Re: Features for my new DAC?
« Reply #7 on: 25 Jun 2019, 03:18 am »
Please add me to the audition tour.

For $3500 I would expect remote volume control/mute for connecting direct to amp, unless the SQ punches much higher than current popular ~$3k DACs (DS Sr)

Familiar with Burson regulators?

audioengr

Re: Features for my new DAC?
« Reply #8 on: 25 Jun 2019, 04:18 am »
Please add me to the audition tour.

For $3500 I would expect remote volume control/mute for connecting direct to amp, unless the SQ punches much higher than current popular ~$3k DACs (DS Sr)

Familiar with Burson regulators?

I hear you.  This would be nice, but it would push the price much higher.  Most of my customers are using their app to control muting and even volume control, but most are using an active preamp.

I expect this DAC to crush everything up to the $15K range at least, so I don't think this is necessary.  I think it will be a giant-killer in this price-range.  The DAC should probably be used with an active preamp to get the best slam from it anyway.  If it is driving a tube amp, maybe a transformer passive would work well enough.

I'm familiar with Burson and Hynes regs.   I have a license from Hynes to design my own versions, which I do.   Based on the specs, the regulators I'm using will actually be better.  Lower noise, better input noise rejection and faster response with smaller overshoot.

Steve N.

audioengr

Re: Features for my new DAC?
« Reply #9 on: 25 Jun 2019, 04:19 am »
$3500 is retail or wholesale?

Retail.

Steve N.

richidoo

Re: Features for my new DAC?
« Reply #10 on: 26 Jun 2019, 01:55 am »
Yeah, Roon/JRiver have decent software volume controls, but preamp preferable to me too.


The DAC should probably be used with an active preamp to get the best slam from it anyway.  If it is driving a tube amp, maybe a transformer passive would work well enough.

Is 50kOhm high enough load for optimum performance?  It has a discreet SS output stage I assume?


I expect this DAC to crush everything up to the $15K range at least,

Coming from you, that's quite a statement. I'm excited to hear it!
Rich

MarkR7

Re: Features for my new DAC?
« Reply #11 on: 26 Jun 2019, 02:43 am »
Would love to see an AES/EBU input as well! I’d like to get on the list to hear it too.

Delta77

Re: Features for my new DAC?
« Reply #12 on: 26 Jun 2019, 03:30 pm »
Just purchased the innuOS ZEN (should be coming soon), and am now looking for a DAC that would pair nicely with it..
Currently using a Oppo 205 as DAC / Volume control..
I may want to be on the list for a Trial..?? 

audioengr

Re: Features for my new DAC?
« Reply #13 on: 26 Jun 2019, 05:34 pm »
Yeah, Roon/JRiver have decent software volume controls, but preamp preferable to me too.


Is 50kOhm high enough load for optimum performance?  It has a discreet SS output stage I assume?

Should be fine down to ~2K.  The output impedance will be around 20 ohms.  Op-amp output, not discrete.

Steve N.

audioengr

Re: Features for my new DAC?
« Reply #14 on: 26 Jun 2019, 05:36 pm »
Just purchased the innuOS ZEN (should be coming soon), and am now looking for a DAC that would pair nicely with it..
Currently using a Oppo 205 as DAC / Volume control..
I may want to be on the list for a Trial..??

Another customer of mine has an InnuOS and he is deciding on an Off-Ramp 6 or 5 USB converter because his DAC's USB interface is disappointing at best.  This is the case with most DACs.

Steve N.
« Last Edit: 28 Jun 2019, 06:02 pm by audioengr »

A_shah

Re: Features for my new DAC?
« Reply #15 on: 28 Jun 2019, 09:10 am »
 @ Delta 77
Congratulations ! let us know how InnOus  Sound , have been using the Blue node 2I for a month but will send it back to Amazon and try out the the Cambridge audio CXN V2 which I have ordered today , Also ordered  a Focal Stelia headphones !  Since you mentioned Innous have been looking at  the possibility of getting one and trying it out ! , to be honest i am satisfied with the SQ & the options available with BS node 2i I have used it as a DAC as well as a transport with the PS audio DirectStream DAC  :popcorn: :thumb:

Asghar

andrewd01

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Re: Features for my new DAC?
« Reply #16 on: 18 Jul 2019, 05:56 pm »
Hi Steve,

Sounds like an interesting product.
I would prefer the SPDIF input to be an optional extra.  I would prefer to only pay for the inputs needed.  I like the idea of one input only as it eliminates ugly switches on the casework (and also simplifies the circuit, which cant be a bad thing).

Instead of IEC, would it be possible to have an option where you can order it configured to run off a Dynamo (12V DC)? 

audioengr

Re: Features for my new DAC?
« Reply #17 on: 18 Jul 2019, 08:54 pm »
Hi Steve,

Sounds like an interesting product.
I would prefer the SPDIF input to be an optional extra.  I would prefer to only pay for the inputs needed.  I like the idea of one input only as it eliminates ugly switches on the casework (and also simplifies the circuit, which cant be a bad thing).

I can only do 2 versions, not three.  The versions are 2 different input modules.  The S/PDIF input must be on-board, so no module.  These are the constraints for making an affordable DAC that I can sell through dealers. One circuit board, one chassis, one set of panels. 

All of the options on the Overdrive DAC prevent it from being something I can sell through dealers. It would have to be $50K and that is a non-starter.

If I eliminated the modules, I would have to make custom front panels with no input select pushbutton hole and custom back-panels with no module hole.  It would be less expensive, but recouping my costs for the different panels would be difficult.  I cannot just buy 10 of each.  They would be too expensive, like $100 each.  Then I need to rework the baseboard so that the S/PDIF is always selected.  Manual rework adds a lot of cost.  Cannot have it on this product.

Quote
Instead of IEC, would it be possible to have an option where you can order it configured to run off a Dynamo (12V DC)?

It will have one configuration and that is AC input.  It needs multiple power supply voltages, so a single external DC supply would not work.  The Overdrive uses 3 external DC supplies.

Steve N.

andrewd01

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Re: Features for my new DAC?
« Reply #18 on: 19 Jul 2019, 06:47 am »
Ok, thanks Steve

audioengr

Re: Features for my new DAC?
« Reply #19 on: 25 Aug 2019, 12:15 am »
Some photos of the SOTAPRAT DAC:







Photo of the inside will come later.  It's being debugged.

for those not familiar with the lingo, SOTAPRAT is State of the Art Pace Rhythm and Timing. 8)

Steve N.