[fjrabon]

   
Thank you for taking the time to answer my question. However, your answer raises new questions.
 
I've read about the hybrid volume control, but it's still not clear to me where the digital volume control operates. Mostly, I don't get what's so 'hybrid' about it. Let's forget the second gain stage for a while. Let's say I'll never be using that part, because I only go up to 90.5. I assume then that the 0-90.5 dB are controlled fully in the digital domain, correct?
 
And what do you mean by theoretically it wouldn't need dithering? Assuming a realistic maximum of 20 bits of SNR (= 120 dB), this would leave 12 bits for volume control, = 72dB. This is less than 90.5, so if there wasn't any dithering done, there would be truncation, right? Or am I missing something?

Grace gives a -190dB artifacts level from full-scale.  I guess this is coming simply from 32X6 = 192?  With 2dB lost somehow else?  
 
edit: Thinking about this again, I guess this means they are using their ANSR dithering adapted to 32 bit, which would make the 190 number make sense, as in such case they're saying that the LSB dithering only throws away ~1/3 of the last bit, giving -190dBR artifacts.  

 

[a1right]

than you.

   
Thank you for taking the time to answer my question. However, your answer raises new questions.
 
I've read about the hybrid volume control, but it's still not clear to me where the digital volume control operates. Mostly, I don't get what's so 'hybrid' about it. Let's forget the second gain stage for a while. Let's say I'll never be using that part, because I only go up to 90.5. I assume then that the 0-90.5 dB are controlled fully in the digital domain, correct?
 
And what do you mean by theoretically it wouldn't need dithering? Assuming a realistic maximum of 20 bits of SNR (= 120 dB), this would leave 12 bits for volume control, = 72dB. This is less than 90.5, so if there wasn't any dithering done, there would be truncation, right? Or am I missing something?

thank you

 

[MonkCanatella]

 
Grace gives a -190dB artifacts level from full-scale.  I guess this is coming simply from 32X6 = 192?  With 2dB lost somehow else?  
 
edit: Thinking about this again, I guess this means they are using their ANSR dithering adapted to 32 bit, which would make the 190 number make sense, as in such case they're saying that the LSB dithering only throws away ~1/3 of the last bit, giving -190dBR artifacts.  

 
 
Have you ever noticed a difference in dithering algorithms? Or in digital volume control in general?

 

[kenman345]

I was trying to figure this out for certain. It says that Windows USB will only support up to 346Khz. So that means it cannot support DSD playback even with jRiver?

 

[fjrabon]

Have you ever noticed a difference in dithering algorithms? Or in digital volume control in general?

Not with 32 bit. With 16 bit, yes.

 

[Michgelsen]

I was thinking, it is also quite likely that the built-in digital volume control of the AK4490 DAC is used. Unfortunately, its datasheet does not provide any insight in the use and type of dithering.

 

[Hi-Fi EDU]

  I was thinking, it is also quite likely that the built-in digital volume control of the AK4490 DAC is used. Unfortunately, its datasheet does not provide any insight in the use and type of dithering.

 
It may not answer your question(s), but this document was a pretty interesting read about the m9XX and its design:
 
http://www.gracedesign.com/support/whitepapers/m9XX_tech_discussion_Rev3.pdf

 

[3-50]

New firmware:
https://www.dropbox.com/s/eu5kj6oqmfno3e6/m9XX_0x0102_DFU.zip?dl=0
 
4update use:
C:\Program Files\XMOS\USBAudioStDriver_306A\xmosusbaudiost306A_dfuapp.exe

 

[Michgelsen]

Yes, I've read that. Unfortunately, it does indeed not answer my question.

 

[fjrabon]

  Yes, I've read that. Unfortunately, it does indeed not answer my question.

ultimately, I don't think it really matters what type of dithering it uses with 32 bit processing.  Though I am intellectually curious.

 

[NeoWilson]

Hi guys, just got my m9xx today, want to make sure my settings are correct to play DSD music via JRiver. I installed the XMOS driver. CF U d.d. PL F1 U2 19
 

 

[MonkCanatella]

When you access the menu, you can see if your amp is using DSD input by scrolling as far to the right as possible. This last menu item tells you the current input rate. it'll say dd or something like that. if it's a number, it's not using DSD.

 

[fjrabon]

  Hi guys, just got my m9xx today, want to make sure my settings are correct to play DSD music via JRiver. I installed the XMOS driver. CF U d.d. PL F1 U2 19

last number indicates it's playing 192kHz, not DSD.
 
http://www.gracedesign.com/support/manuals/m9XX_Owners_Manual_RevE.pdf is the manual.  
 
Quote:

  When you access the menu, you can see if your amp is using DSD input by scrolling as far to the right as possible. This last menu item tells you the current input rate. it'll say dd or something like that. if it's a number, it's not using DSD.

it'll say either "d1" (DSD 64) or "d2" (DSD 128).  "dd" is display dimmer mode off, "d.d." is display dimmer mode engaged.

 

[Solarium]

Wait so this means that if I don't use over 90% volume that the 2nd USB power does not get used at all? I might have missed the earlier thread discussions. So 75% volume with or without the 2nd USB is the same volume? If I don't ever use higher than 80% then I shouldn't be using the 2nd USB cable right?

tried looking through the forums for this, but can't find it. Anyone care to explain? I tried switching between the 2 modes, and haven't noticed much difference in the volume. The high powered mode may sound a little bit more bassy tho

 

[kenman345]

 
tried looking through the forums for this, but can't find it. Anyone care to explain? I tried switching between the 2 modes, and haven't noticed much difference in the volume. The high powered mode may sound a little bit more bassy tho

 
I just bought a unit second-hand but, looking at the output ratings on Massdrop page, it seems that the biggest difference you will notice will come from the use of low impedance headphones. The higher impedance headphones you use, the less margin of difference the two power levels have. I have only about 2 hours of usage on mine and have not tried the high power level, but I am using 250 Ohm and 320 Ohm headphones so I am not expecting a huge difference in power/drive. I think the main difference will be that if you are using USB for the audio signal that you might have a little cleaner power coming in when in high-power mode.