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Review and Measurements of Massdrop x Grace Design SDAC

flipflop

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The key aspects of ASR that diffentiates it from others are, IMHO:
— “Standardized” measurements method applied across products.
— Measurements are reported graphically in a uniform manner, with very useful annotations.
— Equipment are loaned by individuals or purchased by Amir.
— The ASR site is not literred by advertising banners.
Rtings.com do the same things, but with TVs, headphones, and PC monitors.
 

trl

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I hear you but it is a lot of work. :) And would slow down reviewing new gear. Let me think about it.

Can't you find some students to start an apprenticeship? It could be a win-win. :)
 

Roen

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Were there any measurements done on the new dashboard for the SDAC in either unbalanced or balanced?
 
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amirm

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You can eyeball it from this graph:

index.php


Second harmonic alone is at -100 dB so that would set the best case SINAD value at 100.
 

WondrousHippo

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You can eyeball it from this graph:

index.php


Second harmonic alone is at -100 dB so that would set the best case SINAD value at 100.

On the one hand, I know even at those numbers, this doesn’t really matter.

On the other, upgrade-itis is suddenly setting in. Using an SDAC and Sabaj D4 for now.
 

Roen

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Did you get a chance to put this DAC on your new Dashboard with updated SINAD numbers?
 

Veri

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Did you get a chance to put this DAC on your new Dashboard with updated SINAD numbers?
I don't think he has it anymore! >> "on kind loan from a member"
 

Roen

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Ah....I'll see if I can't drum up some volunteers.
 

catman

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This is a review and detailed measurements and comparison of Massdrop Grace Design SDAC DAC. It is on kind loan from a forum member. The "drop" is over but when it was active, the unit costs $79. See it, and the detailed specs here: https://www.massdrop.com/buy/massdrop-x-grace-design-standard-dac.

The unit is similar size to JDS Labs OL DAC ($99 plus shipping) which I compared it to in this review:

View attachment 11659

Clearly they are after the same market and audience. While both have decent heft for what they are, they are both too light so support heavy cables and such.

The JDS OL DAC comes with an external linear power supply while the Grace SDAC is USB powered. The designer, Michael Grace, has written a nice post about the SDAC here: https://www.massdrop.com/buy/massdrop-x-grace-design-standard-dac/talk/1806625. Reading that, seems like good engineering has gone into the device beyond just slapping a reference design in a box. Measurements of course will tell if that is, or is not the case.

The unit is UAC 2 compliant meaning it worked without installing and drivers in Windows 10 Creators edition. I tested it as I do all other USB DACs using Roon in "exclusive" WASAPI interface which gives bit-exact access to the DAC.

I am sure you are anxious to see the measurements so let's get into that. If you are not familiar with my measurements, I suggest reading my tutorial on audio measurements here: https://www.audiosciencereview.com/forum/index.php?threads/understanding-audio-measurements.2351/

And oh, unless I specifically say otherwise, I have no relationship to these or any other manufacturers.

Measurements
Let's start simple and look at frequency response measurements using 48 kHz sampling:

View attachment 11660

I was surprised to see that early roll off in OL DAC's response starting at just 10 kHz. The graph has very fine scale so that is not a large drop but still, at 48 kHz sampling, I expect to see pretty flat response to 20 kHz which the Grace SDAC delivers. Importantly the SDAC has higher output which may be necessary to drive some power amplifiers to their maximum output. The SDAC output is 2.16 volts RMS whereas the OL DAC was 2.00 volts (@ 1 kHz).

Channel matching while not an issue, was slightly worse on SDAC than OL DAC as you can (barely) see in the graphs.

Next let's look at jitter and noise with a 24-bit, 48 kHz signal. Everything other than the main tone at 12 kHz is undesirable:

View attachment 11661

The Grace SDAC nails this test with a flat, low noise floor free of any distortion or noise spikes. The OL DAC does nearly as well but its noise floor is a few dB higher and we see widening of the 12 kHz "skirts" which indicates some amount of random jitter. Mind you, these are all, literally in the noise and the OL DAC response is very good. Still, in a race to best engineering, the SDAC wins here by a bit.

Linearity test is the favorite for everyone so let's see how they both did:

View attachment 11662

Both provide good performance but the SDAC again pulls ahead by a bit. The same is reflected in time domain response of a low level, -90 dB sine wave:

View attachment 11663

Next let's feed them a 1 kHz tone, filter that out from their output and see what remains:

View attachment 11664

While the SDAC shows lower noise, in a reversal of fortunes, it has higher harmonic distortion than the OL DAC. Some or all of this may be due to higher output it provides. I had no good way of taking that effect out of that this test.

Let's look at how the harmonic distortion and noise act versus level:

View attachment 11690
The OL DAC shows a lower (but insignificant) amount of THD+N than SDAC. Both display a bit more distortion close to their maximum output level. Note that these are at 400 Hz rather than the more common 1 kHz (limitation of the test file I am using at the moment).

Conclusions
We have a bit of mixed picture in the measurements here relative to the two DACs under test. Overall though, I would give the nod and recommendation to Grace SDAC for exemplary jitter response, lower noise floor, higher output and flat frequency response. Its harmonic distortion is higher than I like but in this price bracket and audibly, not a concern.

It is clear there is good engineering behind Grace SDAC. It is also a good value at just $79 from Massdrop. Alas, you can't buy the unit right now so take that into account when deciding what to purchase.

Edit: fixed the comment about output levels and updated the measurement/graphs for THD+N.

As always, questions, comments, corrections, etc. are all welcome.
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catman

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Many thanks for this review, as always. I have a quick question please. While this thing does work with computers, is there a way to eke out sound from an iPhone? I connected it using an Apple camera adapter, with the lightening going to power and the USB out going to the SDAC. The red light on the DAC lights up, but there is absolutely no sound! What am I doing wrong?
 

Reckless5040

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Many thanks for this review, as always. I have a quick question please. While this thing does work with computers, is there a way to eke out sound from an iPhone? I connected it using an Apple camera adapter, with the lightening going to power and the USB out going to the SDAC. The red light on the DAC lights up, but there is absolutely no sound! What am I doing wrong?
Which adapter are you using? I have read that the older camera adapters dont work. https://www.reddit.com/r/headphones/comments/9wpt9r/_/e9myg6d ( I hope theres no rule against posting to reddit)
 

catman

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You are right. I had indeed tried an older adapter, as well as one that Massdrop recommended. What works is the USB 3 adapter.
 

Dalbry91

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I am currently using a Grace SDAC and Massdrop O2 as my pc DAC/Amp. I just ordered a Modi 3 and JDS Labs Atom to possibly replace them so I can use my PS4 and PC together with the same dac. I will be giving the SDAC or old Modi Multibit (bought before lurking this forum) with the O2 to my wife for her pc. Would you consider the Modi 3 better all around than the SDAC? My OCD wants to have the best DAC in use if possible, and I want to keep my desk clutter free.
 
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Veri

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I am currently using a Grace SDAC and Massdrop O2 as my pc DAC/Amp. I just ordered a Modi 3 and JDS Labs Atom to possibly replace them so I can use my PS4 and PC together with the same dac. I will be giving the SDAC or old Modi Multibit (bought before lurking this forum) with the O2 to my wife for her pc. Would you consider the Modi 3 better all around than the SDAC? My OCD wants to have the best DAC in use if possible, and I want to keep my desk clutter free.
I think they are damn near the same in performance honestly, via s/pdif modi3 might have the edge otherwise it's a toss-up
 
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