Review and Measurements of Grace Design Balanced DAC

[trl]

I wonder is my $120 balanced amplifier truly balanced! Makes a T50RP rattle like no other! https://www.aliexpress.com/item/33040446809.html?spm=a2g0s.8937460.0.0.7bcb2e0ebcaVRr

It definitely looks balanced to me, with 2 x TPA6120A2 output buffers, so I think it's fully balanced. By rattle you really mean rattle, like diaphragm rattle? If so, then feel free to RMA your T50RP...it's probably the mk3 that has rattling drivers (Q&A issues).

 

[AresHarvest]

I have two pairs of T50RP mk3. The first pair had significant rattle in on both sides, though one more intense than the other. If I recall it was excited the most somewhere in the 20-30 Hz range.

Fixed by taking off the earpads and foam pad, then tightening the 4 screws (gently, to prevent stripping). Second pair had significant rattle on only one side, again fixed by the above method.

 

[amirm]

As long as you're using decent quality RCA cables you shouldn't get any hum whatsoever, correct?

No. You get ground loops because the differential between the chassis of the two gears you are connecting high enough to create voltage drop across your cables. Think of it as two lakes connected by a channel. If one is higher than the other, water flows across the channel. In this case, the channel is your RCA interconnects. Since you have no control over chassis voltage in your equipment, ground loops/hum may hit you at any time. Indeed it is present in majority of RCA outputs I test. Fortunately our hearing sensitivity at 60 Hz is quite poor so it takes a lot of leakage/voltage drop to create an audible problem.

XLR balanced connections avoid this problem because the chassis ground is not used as a reference for audio signal. So the current can flow between the two pieces but won't change the audio signal.

 

[AresHarvest]

XLR balanced connections avoid this problem because the chassis ground is not used as a reference for audio signal.

Unless there is a "pin 1 problem" http://pin1problem.com/

 

[VintageFlanker]

Can anyone beat this all-in-one’s performance/features to price ratio?

Aune X1S Pro, probably, but a touch more expensive.

 

[Tup3x]

I still can’t get over how good the DX3 Pro is..

Can anyone beat this all-in-one’s performance/features to price ratio?

Doesn't SoundBlasterX G6 offer superior value and features for less? Granted, not balanced but SINAD is better. I assume that by "this" you do not mean DX3 Pro.

 

[samshaver]

For my testing I used USB

Was this your standard USB or your USB 3?!? Did you have to do anything special with a powered hub or something to overcome the issues that the USB powered SMSL units had?!?

Here or Here

 

[amirm]

Was this your standard USB or your USB 3?!? Did you have to do anything special with a powered hub or something to overcome the issues that the USB powered SMSL units had?!?

I always use the hub in my monitor which also supports USB 3.0. If that doesn't work for some reason, I switch to using the USB 2.0 connectors on my desktop. I didn't have to do it here.

 

[ZeDestructor]

Honestly, unless you are driving some ridiculously inefficient headphones, a good SE DAC will work just fine with the 789. Especially in the case of highly efficient headphones, you get more usable volume adjustment going with SE anyway.

The 789 sums the balanced input down into a basic SE output before feeding it into all 3 of it's amps (SE stereo, and 2x mono balanced). Thet means that you can use SE input to drive both balanced and SE output, just as you can use balanced input to drive both balanced and SE output.

 

[covertash]

The 789 sums the balanced input down into a basic SE output before feeding it into all 3 of it's amps (SE stereo, and 2x mono balanced). Thet means that you can use SE input to drive both balanced and SE output, just as you can use balanced input to drive both balanced and SE output.

Yep, I know.

My point was regarding the volume output and its relationship to using an SE or balanced output DAC. With an SE DAC, you will have more usable volume adjustment in the lower gain levels with sensitive headphones. If your sensitive headphones were already loud at 12 o'clock (or less) on Gain 1 with an SE DAC, then you're going to have even less room to work with going balanced thanks to the 6 dB (or more) attenuation - depending on which balanced DAC is used.

 

[ZeDestructor]

Yep, I know.

My point was regarding the volume output and its relationship to using an SE or balanced output DAC. With an SE DAC, you will have more usable volume adjustment in the lower gain levels with sensitive headphones. If your sensitive headphones were already loud at 12 o'clock (or less) on Gain 1 with an SE DAC, then you're going to have even less room to work with going balanced thanks to the 6 dB (or more) attenuation - depending on which balanced DAC is used.

I'm not sure about how the THX and massdrop engineers et things up on the 789, but if I were on the team, matching the input levels so that the 4V balanced input is as loud as the 2V SE input would be fairly high up on my list of things to do as part of engineering it. Sadly, I neither have a 789to test (yet.. I'm in the November batch), nor a balanced DAC, so I can't confirm.

 

[covertash]

I'm not sure about how the THX and massdrop engineers et things up on the 789, but if I were on the team, matching the input levels so that the 4V balanced input is as loud as the 2V SE input would be fairly high up on my list of things to do as part of engineering it. Sadly, I neither have a 789to test (yet.. I'm in the November batch), nor a balanced DAC, so I can't confirm.

I'm not sure why you would deliberately want to make the balanced input have the same loudness as unbalanced - can you please explain what the advantage would be? To me, having the additional gain is one of the few key benefits of going with a balanced DAC, particularly if the end goal is to be able to use hard to drive headphones (which, admittedly are few and far between nowadays). Although, with the 789 you would need to find a way to attenuate -6 dB in order to have full voltage swing on Gain 3 without clipping.

With that said, I had shared my unorthodox test (using the 789 and SDAC Balanced) running both the unbalanced and balanced outputs from the SDAC-B to the 789 here. In short, the balanced input is louder across the board, regardless if using the XLR, 1/4", or 3.5 mm headphone connectors.

 

[ZeDestructor]

I'm not sure why you would deliberately want to make the balanced input have the same loudness as unbalanced - can you please explain what the advantage would be? To me, having the additional gain is one of the few key benefits of going with a balanced DAC, particularly if the end goal is to be able to use hard to drive headphones (which, admittedly are few and far between nowadays). Although, with the 789 you would need to find a way to attenuate -6 dB in order to have full voltage swing on Gain 3 without clipping.

With that said, I had shared my unorthodox test (using the 789 and SDAC Balanced) running both the unbalanced and balanced outputs from the SDAC-B to the 789 here. In short, the balanced input is louder across the board, regardless if using the XLR, 1/4", or 3.5 mm headphone connectors.

Interesting, I figured that they'd have attenuated the balanced input by 6dB (by halving the 4V to 2V) to make things consistent across inputs for typical sources... That said, given the 789 can do +10dB or +16dB gain depending on output, I don't think the input matters all that much. I can definitely see the attraction for it though.

Hmm.. to get a balanced SDAC now, wait for the inevitable D70s, or pickup a D50s... questions, questions...

 

[covertash]

Interesting, I figured that they'd have attenuated the balanced input by 6dB (by halving the 4V to 2V) to make things consistent across inputs for typical sources... That said, given the 789 can do +10dB or +16dB gain depending on output, I don't think the input matters all that much. I can definitely see the attraction for it though.

Hmm.. to get a balanced SDAC now, wait for the inevitable D70s, or pickup a D50s... questions, questions...

One thing to keep in mind is if you do use the balanced input, you cannot pass the signal through the SE line out. It's not a big deal if the 789 is going to be your one and only headphone amp, and you also don't use any studio monitors.

As far as DAC choices, yeah, it's hard to go wrong with any of the above. Personally, I chose the SDAC-B, before any reviews were released, because of the great experience I have had with the regular SDAC - it's a simple device that sounds good, and hasn't shown any reliability issues. Most importantly, for me, was that the DAC had to be USB-powered to save on needing an additional power port, followed closely by having TOSLINK available. Technically, a Schiit Modi 3 (which, I also have) fulfills these same requirements as well, for less money, but yeah... new toy... and all that joy.

 

[firedog]

Excuse me for asking, but I’m curious: do you hear any difference between these DACs in listening under matched conditions? Or are the measurements similar enough that it makes no difference? If that’s the case, the only purchase decision factors would be features vs. price.

 

[ZeDestructor]

One thing to keep in mind is if you do use the balanced input, you cannot pass the signal through the SE line out. It's not a big deal if the 789 is going to be your one and only headphone amp, and you also don't use any studio monitors.

As far as DAC choices, yeah, it's hard to go wrong with any of the above. Personally, I chose the SDAC-B, before any reviews were released, because of the great experience I have had with the regular SDAC - it's a simple device that sounds good, and hasn't shown any reliability issues. Most importantly, for me, was that the DAC had to be USB-powered to save on needing an additional power port, followed closely by having TOSLINK available. Technically, a Schiit Modi 3 (which, I also have) fulfills these same requirements as well, for less money, but yeah... new toy... and all that joy.

The lack of passthrough is no big for me - I run 7.1 seperately for my speaker setup (might get amir to bench my soundcard eventually), and like you I need the TOSLINK. Powering it I'm not fussed at all about USB vs AC adapter.

I think I'll end up with the SDAC-B and get the D70s later if I care enough for it (afterall, the only reason I'm picking a 789over the atom isso thatI can feed silly power into planars later on down the line). The SE output on the SDAC-B is just the cherry on top.

Excuse me for asking, but I’m curious: do you hear any difference between these DACs in listening under matched conditions? Or are the measurements similar enough that it makes no difference? If that’s the case, the only purchase decision factors would be features vs. price.

Not really, no. I myself am only considering the SDAC-B cause I think I have a ground loop somewhere in my setup, and I don't want that to annoy me when I get my 789. Going up to the D50s or D70s would be primarily so I can add bluetooth receivership for my phone for the rare times I'm fiddling with the desktop, and a secondary nerdy preference for chasing absolute top-tier performance.

 

[covertash]

Excuse me for asking, but I’m curious: do you hear any difference between these DACs in listening under matched conditions? Or are the measurements similar enough that it makes no difference? If that’s the case, the only purchase decision factors would be features vs. price.

For me, the sound differences are so small that it's not really worth mentioning, if they even truly exist. From my own experiences, level matching DAC's is a major pain to do, as-is, let alone doing it blind or double blind, without having a bunch of intermediary devices in between. My mindset is if I need to turn my desk into a mini laboratory experiment, only to have to strain and try to hear any sort of difference, I'd rather focus my energy on things that are more obvious, such as the features that are being offered. To me, that level of critical listening is more work than I care to do; which is exactly the opposite reason of why I choose to enjoy listening to music in the first place.

Even when it comes to measurements, beyond a certain point, it's really become just an engineering dick measuring contest, that exceeds our threshold of hearing anyway - not to diminish what this site has done for the community, in the slightest. In my opinion, if a DAC measures somewhere within the 2nd or even upper 3rd level tier, it's likely you would be hard pressed to notice any shortcomings, in sound, if at all.

I think I'll end up with the SDAC-B and get the D70s later if I care enough for it (afterall, the only reason I'm picking a 789over the atom isso thatI can feed silly power into planars later on down the line). The SE output on the SDAC-B is just the cherry on top.

Agreed, the 789 is excellent for planars! Currently, the hardest to drive headphone I have is the Hifiman HE-500, and it sounds glorious out of the 789 through the balanced connection. With the LCD-2 Classic, there's not much of a difference with different amps, but they're also significantly easier to drive to begin with.

 

[Svperstar]

Excuse me for asking, but I’m curious: do you hear any difference between these DACs in listening under matched conditions? Or are the measurements similar enough that it makes no difference? If that’s the case, the only purchase decision factors would be features vs. price.

I heard a big difference between the Modi Multibit and the original Grace Designs SDAC. The Multibit is too dark and blurry. Its sitting in my closet I need to box it up and list it for sale.

 

[Labjr]

No. You get ground loops because the differential between the chassis of the two gears you are connecting high enough to create voltage drop across your cables. Think of it as two lakes connected by a channel. If one is higher than the other, water flows across the channel. In this case, the channel is your RCA interconnects. Since you have no control over chassis voltage in your equipment, ground loops/hum may hit you at any time. Indeed it is present in majority of RCA outputs I test. Fortunately our hearing sensitivity at 60 Hz is quite poor so it takes a lot of leakage/voltage drop to create an audible problem.

XLR balanced connections avoid this problem because the chassis ground is not used as a reference for audio signal. So the current can flow between the two pieces but won't change the audio signal.

Interesting. Does the shield of the balanced cable have to be lifted to isolate ground loops?

 

[Labjr]

Khadas Tone Board balanced should be out soon. Should be an interesting comparison.