Starting Point Systems portable NOS DAC
Sep 25, 2017 at 4:54 PM Post #181 of 508
Hi all,

I've been looking for a budget NOS DAC 'cos everyone should try one, right?

Came across the SPS DAC 3 and have been encouraged by the largely positive impressions here, accepting that a NOS DAC is what it is. Well, one thing led to another and I've gone and pulled le trigger. Le pew pew!

It will be hooked up to a Raspberry Pi with Allo DigiOne HAT, serving up over SPDIF coaxial. It will be interesting to see how it performs with a very low-jitter input signal.

Any thoughts on how it might perform powered either by an Anker power core 5v into micro USB vs. a 15v low-noise SMPS i.e. iFi iPower? If it's in battery buffer mode then it should make little difference, I guess, in theory...
 
Sep 25, 2017 at 5:09 PM Post #182 of 508
Hi all,

I've been looking for a budget NOS DAC 'cos everyone should try one, right?

Came across the SPS DAC 3 and have been encouraged by the largely positive impressions here, accepting that a NOS DAC is what it is. Well, one thing led to another and I've gone and pulled le trigger. Le pew pew!

It will be hooked up to a Raspberry Pi with Allo DigiOne HAT, serving up over SPDIF coaxial. It will be interesting to see how it performs with a very low-jitter input signal.

Any thoughts on how it might perform powered either by an Anker power core 5v into micro USB vs. a 15v low-noise SMPS i.e. iFi iPower? If it's in battery buffer mode then it should make little difference, I guess, in theory...
Not sure how those portable batteries for phones work in terms of power and if its linear or not.
But you can buy a very cheap linear power supply on ebay aswell, so I would suggest that.
 
Sep 26, 2017 at 5:01 AM Post #184 of 508
DAC3 already runs on a battery. You can feed your Rpi with a LPS.

One question though...ALLO is a DAC so does the signal pass-through without processing if you use SPDIF out?

@Haden2866
I have the RPi running quite nice and quietly on a iFi iPower SMPS but will investigate LPS at some point as the price seems to be coming down, at least of unbranded Chinese models. I have a very decent UK-built T-class amp (Temple Audio Bantam Gold) which would benefit from a LPS.

If I understand correctly now, a generic power supply should be OK for the SPS DAC if it is run in battery buffer mode. I have abandoned the idea of using a phone battery, as it is not clear from the details whether the DAC would see the power from the USB input when in SPDIF mode.

Allo do make a number of DACs, but the DigiOne is a transport only, with BNC and RCA digital coaxial output.

There's some good reviews of it out there including this one by John Darko. I'm having fun with mine running Volumio on the RPi, using the Volumio iPhone app to control it over wifi. I have installed Roon Bridge on the RPi and got halfway through configuring it before my Roon subscription expired - I may pick Roon up again after we move house but it's on the don't need luxury list for now.

Edit: Ha ha! Unlike a new DAC which is clearly on the must-have essentials list. Someone help me.

So, a very quiet RPi serving up digital over RCA coax with an output jitter measurement that Allo claim is < 1ps into a battery-powered NOS DAC should, all things being equal, sound pretty nice.

*hurries up and waits*
 
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Sep 26, 2017 at 5:34 AM Post #185 of 508
I have the RPi running quite nice and quietly on a iFi iPower SMPS but will investigate LPS at some point as the price seems to be coming down, at least of unbranded Chinese models. I have a very decent UK-built T-class amp (Temple Audio Bantam Gold) which would benefit from a LPS.

If I understand correctly now, a generic power supply should be OK for the SPS DAC if it is run in battery buffer mode. I have abandoned the idea of using a phone battery, as it is not clear from the details whether the DAC would see the power from the USB input when in SPDIF mode.

Allo do make a number of DACs, but the DigiOne is a transport only, with BNC and RCA digital coaxial output.

There's some good reviews of it out there including this one by John Darko. I'm having fun with mine running Volumio on the RPi, using the Volumio iPhone app to control it over wifi. I have installed Roon Bridge on the RPi and got halfway through configuring it before my Roon subscription expired - I may pick Roon up again after we move house but it's on the don't need luxury list for now.

Edit: Ha ha! Unlike a new DAC which is clearly on the must-have essentials list. Someone help me.

So, a very quiet RPi serving up digital over RCA coax with an output jitter measurement that Allo claim is < 1ps into a battery-powered NOS DAC should, all things being equal, sound pretty nice.

*hurries up and waits*
I am running Volumio on RPI too. Thought of picking up the ifi power but backed out twice. I wonder how much difference does it make feeding Rpi with ifi power. And if you have ifi power I think you don't need LPS for Rpi atleast. Will pick ALLO, thanks for the clarification. As for the DAC3, it's the R2R you can find and absolute steal for anything under budget IMO.
 
Sep 26, 2017 at 6:01 AM Post #186 of 508
I am running Volumio on RPI too. Thought of picking up the ifi power but backed out twice. I wonder how much difference does it make feeding Rpi with ifi power. And if you have ifi power I think you don't need LPS for Rpi atleast. Will pick ALLO, thanks for the clarification. As for the DAC3, it's the R2R you can find and absolute steal for anything under budget IMO.
I'm not sure how much difference it makes, but I have had good success with another iPower on a phono pre-amp which transformed its performance. We bought the RPi as part of a Kano kid's coding kit for my daughter and it came with a really noisy, like you can hear it buzzing, power supply. My daughter hasn't quite caught the coding bug as well as we would have liked so I have re-purposed the Pi. OK I've nicked it haven't I, I admit. The output from the Allo DigiOne in this configuration is really quiet, like none more black, if you're familiar with the movie Spinal Tap. It's good to know the iPower is there, so I don't have to think about whether it could be any quieter. YMMV, of course.

I watched the crowdfunding video on the SPS website last night. M. Mariac seems like a really cool guy. We are very lucky having folk like him making us such funky toys.
 
Sep 26, 2017 at 8:30 AM Post #187 of 508
Just got myself an Audio-gd R2R-11 (USD 350, discrete resistor ladder DAC, NOS). Review to follow.
 
Sep 26, 2017 at 9:06 PM Post #189 of 508
Sep 26, 2017 at 9:27 PM Post #190 of 508

Any idea if DA-8 are 16-bit modules? I would think so given the discussion on the R2R 2 page, where he talks that even the most precise resistor tolerance of 0.01% isn't enough to provide full 16-bit resolution, so FPGA correction is used there. Seems that R2R 11 doesn't have the FPGA correction onboard so do we even get 16 bit resolution or close?
 
Sep 26, 2017 at 9:33 PM Post #191 of 508
For what it's worth, some of the early CD players worked well with 14-bit architecture (Meridian MCD Pro, anyone?).
 
Sep 26, 2017 at 9:39 PM Post #192 of 508
According to Audio-gd:

Two pcs DA 8 modules equipped with ultra-high speed CPLD processors to correct the discrete resistor ladder. Unique parallel processing to achieve superb performance .

I just assumed it was referring to a FPGA.
 
Sep 26, 2017 at 9:43 PM Post #193 of 508
Anyhow, the proof of the pudding is in the eating!

So far (not burned-in and fed by a cheap DAP), initial results have been promising. Good midrange resolution and articulation, wide soundstage. Treble is a little sharp and there could be better bass extension. Hopefully this will resolve itself with a better source and more use. Also, I would like to use it purely as a DAC with my SA-31 amp.
 

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