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Review and Measurements of Grace Design Balanced DAC

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#43
i recommend getting d50s instead unless you really want the balanced out.
I will be needing balanced XLR output for my eventual 789 shipping out in November. However, I am definitely considering the D50s, Khadas Tone board or the upcoming DX7 Pro for my in-the-mail JDS Labs Atom.
 

JohnYang1997

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#44
I will be needing balanced XLR output for my eventual 789 shipping out in November. However, I am definitely considering the D50s, Khadas Tone board or the upcoming DX7 Pro for my in-the-mail JDS Labs Atom.
789 is single ended internally. It converts balanced signal to single ended first then convert to balanced again for headphone output. So you don't really need balanced output from dac. Just get a better dac which d50s is.
 
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#45
Correct me if I'm wrong.. Doesn't a DAC require 2 chips to be truly balanced? Dual mono? I just started this hobby and have limited understanding as to the components of a DAC..
In the more common, traditional sense, you are correct. This implementation is outputting a balanced signal from the one chip, which is a big part of the reason why the cost is lower, and the physical footprint of the DAC is much smaller as well.

Even still, you are getting much of the benefits of going balanced with better common mode noise rejection (good for long cable runs, or high EMI environments), and higher output voltage - translating to a 6 dB increase in volume - assuming you have really hard to drive headphones. Plus, the SDAC Balanced offers additional inputs (coaxial/TOSLINK), if that makes any difference to you.
 
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#46
789 is single ended internally. It converts balanced signal to single ended first then convert to balanced again for headphone output. So you don't really need balanced output from dac. Just get a better dac which d50s is.
If I were to do that, can I use just any old RCA splitter for both AMPs?
 
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#48
If I were to do that, can I use just any old RCA splitter for both AMPs?
If you are getting the 789, then your (unbalanced) DAC can connect to the 789, and then use the RCA line out from the 789 to feed the Atom. No splitter even needed.

This is exactly how I had it set up in order to run both my 789 and STAX SRM-252S amp at the exact same time.
 

Tks

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#49
I will be needing balanced XLR output for my eventual 789 shipping out in November. However, I am definitely considering the D50s, Khadas Tone board or the upcoming DX7 Pro for my in-the-mail JDS Labs Atom.
You're have lots of great stuff coming in eh :D
 
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amirm

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Thread Starter #50
789 is single ended internally. It converts balanced signal to single ended first then convert to balanced again for headphone output. So you don't really need balanced output from dac. Just get a better dac which d50s is.
It doesn't matter how the 789 works internally. Using balanced interconnects between the DAC and headphone amp can sharply reduce the probability of ground loops. That is why if you can, you want to use a DAC with balanced output. While people may not hear THD+N effects at -100 dB, they will hear ground loops when or if it happens.
 

Tks

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#51
It doesn't matter how the 789 works internally. Using balanced interconnects between the DAC and headphone amp can sharply reduce the probability of ground loops. That is why if you can, you want to use a DAC with balanced output. While people may not hear THD+N effects at -100 dB, they will hear ground loops when or if it happens.
Hey amir, when you say reduce ground loop issues. Under what circumstances does balanced fail just wondering as I've this lots of times but am not aware on how to seek out a proper answer to something I've wondered. Are there "types of ground loops" or just far more servere distortions that balanced isn't able to overcome so to speak in laymen's terms?
 
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#52
If you are getting the 789, then your (unbalanced) DAC can connect to the 789, and then use the RCA line out from the 789 to feed the Atom. No splitter even needed.

This is exactly how I had it set up in order to run both my 789 and STAX SRM-252S amp at the exact same time.
Wow. Thank you. This works regardless of the input of the DAC or only on RCA unbalanced input?

You're have lots of great stuff coming in eh :D
Hahaha. I guess so. Just trying to narrow down the DAC(s) I will be using.

It doesn't matter how the 789 works internally. Using balanced interconnects between the DAC and headphone amp can sharply reduce the probability of ground loops. That is why if you can, you want to use a DAC with balanced output. While people may not hear THD+N effects at -100 dB, they will hear ground loops when or if it happens.
So if I were interested in balanced output SU-8 V2 is the way to go? Am I guranteed a V2 unit no matter the vendor? It's that or I wait for the other options I mentioned.
 
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#54
Wow. Thank you. This works regardless of the input of the DAC or only on RCA unbalanced input?
Unfortunately, no. If you only use the XLR input on the 789, then you will not be able to use the SE line out. In other words, the SE line out will only output whatever is being fed to the SE input.

Just for curiosity's sake, though, I used both the balanced and unbalanced outputs from the SDAC Balanced, and fed both right into the 789. I confirmed I was able to get the same signal on the 789, playing simultaneously, with just a flick of the input switch in front. (Of course, the obvious difference, being the ~6 dB gain between the two inputs.) Also, since the unbalanced connection was present, naturally, the SE line out continued to work, feeding my STAX amp - regardless of which input was actively being used through the 789 itself.

While I wouldn't necessarily recommend such a convoluted setup to anyone (because you might as well feed the unbalanced signal from the SDAC-B directly to the Atom instead), but the concept does work - I just can't think of any use case to support its existence.
 
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amirm

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SIY

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#58
Correct me if I'm wrong.. Doesn't a DAC require 2 chips to be truly balanced?
No. There's a huge and common misunderstanding about what "balanced" means. Balanced circuits are those that have equal impedances on both legs. So I could make a balanced DAC with one chip driving one leg and the other leg connected to a resistor with the same value as the first leg's source impedance.

Many people confuse balanced outputs with differential outputs. A differential circuit may or may not be balanced, a balanced circuit may or may not be differential. The only thing that matters is equal impedances to achieve the noise rejection of balanced operation.
 
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