Wiim Ultra Gain Via USB

[slartibartfast]

Not sure I fully understand that especially “If you use the WiiM internal DAC then it's worked around by scaling the samples to 32 bits before attenuation” - who said the attenuation is done by the DAC?

It is scaled to 32 bits before any processing I suppose including volume control. With the internal DAC it is left at 32 bits but for USB it is scaled back to 16 bits

 

[andreilchimico]

OK so what are you using as a Power Amplifier?

I use an advance acoustic xa160 which unfortunately doesn't have the ability to adjust the gain...

 

[hgo58]

It is scaled to 32 bits before any processing I suppose including volume control. With the internal DAC it is left at 32 bits but for USB it is scaled back to 16 bits

For USB it should be converted back to the original number of bits (before EQ and volume control). If not then there is something wrong.

 

[Burnside]

For USB it should be converted back to the original number of bits (before EQ and volume control). If not then there is something wrong.

Sounds like it might be a bug then. Unfortunately I can’t check at the moment as my amp is in for repair.

 

[slartibartfast]

For USB it should be converted back to the original number of bits (before EQ and volume control). If not then there is something wrong.

Well yes, I was assuming 16/44.1 as worst case . You still lose the benefit of the 32 bit volume of I understand correctly.

 

[hgo58]

Well yes, I was assuming 16/44.1 as worst case . You still lose the benefit of the 32 bit volume of I understand correctly.

24/96 is all you need for listening. 32 bit and higher sample rate is beneficial for recording, mixing and EQ. So no problem to convert down from 32 to 24 bit after volume control, as I see it

 

[slartibartfast]

24/96 is all you need for listening. 32 bit and higher sample rate is beneficial for recording, mixing and EQ. So no problem to convert down from 32 to 24 bit after volume control, as I see it

Does WiiM do that though. Or does it send the original bit depth out on USB.

 

[TonyE]

Hmm... I don't understand the problem.

Disable the volume in the WiiM ultra. Use it strictly as a bridge to USB to the DAC. Then use the LS15's volume control.

I run my Ultras that way... no volume, no tone controls... just a plain bridge from WiFi (ethernet) to USB. I ran several DACs that way into different preamps... no issues at all. Running Tidal Connect.

I'm also playing with mounting an NAS with lots of WAV music.

 

[TonyE]

Oh.. I reread that... you say that your DAC is driving the preamp too high.

Which Gustard DAC are you using? Can't you control the output voltage in it? Bring it down to 2Vrms max.

 

[hgo58]

Hmm... I don't understand the problem.

Disable the volume in the WiiM ultra. Use it strictly as a bridge to USB to the DAC. Then use the LS15's volume control.

I run my Ultras that way... no volume, no tone controls... just a plain bridge from WiFi (ethernet) to USB. I ran several DACs that way into different preamps... no issues at all. Running Tidal Connect.

I'm also playing with mounting an NAS with lots of WAV music.

I don't think you can bypass the volume control. It can be fixed and 100% but the conversion to 32 bit and back will still happen.

 

[TonyE]

So far as I know, by following the instructions, you can set the "volume to fixed". That means no gain/loss.



Furthermore, since the volume is digital.. if you bypass the entire DAC and go directly to the USB to run an external DAC, then the Ultra's volume shouldn't come into play. ( EDIT: I made an assumption... mea culpa).

I guess I could give it a try since I got an Ultra right behind me, hooked up to a DAC(USB)->preamp->amp->speakers... I have the volume disabled (fixed). My DAC is also set up to unity gain, which means 2Vrms.

OK, playing some Black Sabbath... on account of Ozzie.

Using the remote:

(1) The MUTE button works
(2) The volume does not work, the screen shows 100.

OK, now, disabled the "Fixed Audio Settings"....

(1) Mute works
(2) Volume works... the screen shows the volume up and down (*)

Darn... so the volume works even when outputting over USB. I wonder what it does to the bit depth of the sound...

It looks to me, like his issue is too much gain from his Gustard DAC. Reading in line, some of those units support an external user interface to do configuration... so perhaps he needs to set his DAC analog circuitry to output no more than 2Vrms.

That said, I don't understand his problem... the ARC database https://www.arcdb.ws/model/LS15 specs the LS15 as:

Maximum inputs: 14V RMS maximum balanced, 7V RMS SE.

Which means that preamp can handle a very hot input.

So, I don't understand his problem. Maybe if he would specify the model number for his Gustard DAC?

(*) Mind you.... Black Sabbath sounds much better when the volume is set to AT LEAST 100. Gotta go.... gotta listen for a while. ;-)