dac balanced xlr output impedance question

[ethanhallbeyer]

i have a pair of class-d monoblocks with input impedance of 20 kOhms, output impedance of 70uOhms

my speakers are 1.7i Maggies.

i have tested 3 dacs, only one of which has a volume control:

1. RME ADI-2 DAC FS (has volume control). output impedance: 200ohms
2. Denafrips Ares II. output impedance: 2.4kOhms
3. Xiang Sheng DAC-05a. Line output impedance: 600ohms (i am using xlr out and not sure if it is the same ohms).

Source is iPad Pro via usb-c to usb-c/usb 2.x hub to DAC.

with the Ares II and DAC-05a, the Ares is considerably louder at the same volume. Volume is controlled by iPad OS software control. If I tick up volume to the first lowest setting possible, the ares is almost too loud, the DAC-05a less so.

could someone explain why the Ares II is considerably louder?

when the RME is connected, the iPad OS volume isn’t changeable. volume is adjusted by the remote control. -39db is where the RME sounds decently loud yet not so loud i am concerned about disturbing neighbors that share a same wall.


Thanks i'm advance
]|

 

[Jimbob54]

i have a pair of class-d monoblocks with input impedance of 20 kOhms, output impedance of 70uOhms

my speakers are 1.7i Maggies.

i have tested 3 dacs, only one of which has a volume control:

1. RME ADI-2 DAC FS (has volume control). output impedance: 200ohms
2. Denafrips Ares II. output impedance: 2.4kOhms
3. Xiang Sheng DAC-05a. Line output impedance: 600ohms (i am using xlr out and not sure if it is the same ohms).

Source is iPad Pro via usb-c to usb-c/usb 2.x hub to DAC.

with the Ares II and DAC-05a, the Ares is considerably louder at the same volume. Volume is controlled by iPad OS software control. If I tick up volume to the first lowest setting possible, the ares is almost too loud, the DAC-05a less so.

could someone explain why the Ares II is considerably louder?

when the RME is connected, the iPad OS volume isn’t changeable. volume is adjusted by the remote control. -39db is where the RME sounds decently loud yet not so loud i am concerned about disturbing neighbors that share a same wall.


Thanks i'm advance
]|

Higher voltage output. I wouldnt want to rely on a software volume slider being the only thing controlling the output to the monoblocks either.

 

[LTig]

i have a pair of class-d monoblocks with input impedance of 20 kOhms, output impedance of 70uOhms
[..]
i have tested 3 dacs, only one of which has a volume control:

1. RME ADI-2 DAC FS (has volume control). output impedance: 200ohms
2. Denafrips Ares II. output impedance: 2.4kOhms
3. Xiang Sheng DAC-05a. Line output impedance: 600ohms (i am using xlr out and not sure if it is the same ohms).
[..]
with the Ares II and DAC-05a, the Ares is considerably louder at the same volume. Volume is controlled by iPad OS software control. If I tick up volume to the first lowest setting possible, the ares is almost too loud, the DAC-05a less so.

could someone explain why the Ares II is considerably louder?

Its a design choice of the manufacturer. When CD came on the market in 1982/83 most players did output 2V rms at 0 dBFS (maximum digital signal level) at their unbalanced output. With time some (especially audiophile) makers increased the voltage so they played slightly louder (which gives them a seemingly fuller sound in comparison to normal players). This went so far that one highend player (I seem to remember it was a Spectral but I may be wrong) was measured (AFAIR by Stereophile) at 7V rms. Maybe it was balanced, don't remember.

Regarding the DACs you've tested the Ares would be quieter than the DAC-05a due to its higher output impedance if both had the same rated output voltage.

 

[ethanhallbeyer]

Its a design choice of the manufacturer. When CD came on the market in 1982/83 most players did output 2V rms at 0 dBFS (maximum digital signal level) at their unbalanced output. With time some (especially audiophile) makers increased the voltage so they played slightly louder (which gives them a seemingly fuller sound in comparison to normal players). This went so far that one highend player (I seem to remember it was a Spectral but I may be wrong) was measured (AFAIR by Stereophile) at 7V rms. Maybe it was balanced, don't remember.

Regarding the DACs you've tested the Ares would be quieter than the DAC-05a due to its higher output impedance if both had the same rated output voltage.

im my experience with all else the same but dac, the ares ii was significantly louder. that was at the same minimum ipad software volume setting (near very bottom of vertical graphical control).

 

[ethanhallbeyer]

Higher voltage output. I wouldnt want to rely on a software volume slider being the only thing controlling the output to the monoblocks either.

yeah, i dont feel safe doing that. it was just a test. started with volume all the way down. short of getting an expensive preamp or using rme adi-2 dac which has its own volume knob, i am not sure what i could use to safely control volume from dac -> amps setup, that doesn’t degrade the sound.

 

[LTig]

im my experience with all else the same but dac, the ares ii was significantly louder. that was at the same minimum ipad software volume setting (near very bottom of vertical graphical control).

Are there any specs regarding rated output voltage for both DACS?

 

[ethanhallbeyer]

Are there any specs regarding rated output voltage for both DACS?

this is what i found:

RME ADI-2 DAC FS:

dBu is referenced to 0.775V.
XLR, balanced connection:
+19 dBu, +13 dBu, +7 dBu, +1 dBu @ 0 dBFS
6,91V, 3,46V, 1,73V, 0,87V.
Cinch unbalanced, all 6dB lower:
+13 dBu, +7 dBu, +1 dBu, -5 dBu @ 0 dBFS
3,46V, 1,73V, 0,87V, 0,43V.

Denafrips Ares II:

this is what i could find

Analog Output
RCA at 2.2Vrms 625 Ω
XLR at 4.4Vrms, 1250 Ω

 

[LTig]

This means that the Ares 2.2V will be reduced to 2.07V when feeding typical 10 kOhm load. This is just a tiny bit more than the standard 2V. Therefore the output voltage of the DAC-05a must be quite a bit lower if your experience is correct (which I don't doubt).

 

[Jimbob54]

This means that the Ares 2.2V will be reduced to 2.07V when feeding typical 10 kOhm load. This is just a tiny bit more than the standard 2V. Therefore the output voltage of the DAC-05a must be quite a bit lower if your experience is correct (which I don't doubt).

Think the OP was using the XLR so it would be 4 (ish) V

Interestingly, just found this on the DAC 05a http://www.china-hifi-audios.com/en...-xlr-decoders-digital-analog-converter-p-4702

But I am sceptical given their experience

"Output Level: Balanced output 9V, Standard output 2V" - really?

 

[LTig]

With XLR into 20 kOhm it would be 4.14V for the Ares (loss has the same ratio). If the DAC-05a really has 9V on the XLR it should be significantly louder.