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zapper
2007-09-02, 17:23
If I use the digital out to a dac, does the volume control still work?
Thanks

Skunk
2007-09-02, 18:30
Yes, there's an option in Player Settings>Audio to specify fixed volume or have the volume control adjust the digital output.

But, it's mostly there for convenience adjustments, and not meant to replace analog attenuation. I.e. if you can't turn it up past 30/100 and your amp is capable of blowing your speakers should it accidentally be sent the full un-attenuated signal, then you need inline attenuators or an analog pot of some sort as a precaution.

There's some helpful advice re: attenuation in the Connecting To Power Amp wiki: http://wiki.slimdevices.com/index.cgi?ConnectToPowerAmp

Eric Seaberg
2007-09-03, 09:09
If I use the digital out to a dac, does the volume control still work?
Thanks

As Skunk has already said "YES", it can work and is setable, HOWEVER if you're running into an external DAC then you DON'T want it to control the output, as any change to the digital signal PRIOR to DAC does change the bit-depth. I'd recommend setting the player to DIGITAL OUTPUT LEVEL IS FIXED in the audio settings... of course this only works if your DAC has a volume control on its analog out.

cliveb
2007-09-03, 11:33
As Skunk has already said "YES", it can work and is setable, HOWEVER if you're running into an external DAC then you DON'T want it to control the output, as any change to the digital signal PRIOR to DAC does change the bit-depth. I'd recommend setting the player to DIGITAL OUTPUT LEVEL IS FIXED in the audio settings... of course this only works if your DAC has a volume control on its analog out.
If you're using an external DAC which has 24 bit capability (eg. Benchmark, Lavry, etc), what difference does it make whether you're doing digital volume control prior to the external DAC rather than prior to the Squeezebox's DAC? If you want the convenience of a remote volume control and don't have it elsewhere, then it works just the same.

Eric Seaberg
2007-09-03, 13:05
It's not the same. ANY change to the 24-bit stream while still in the digital domain will change the bit-depth. I know you're probably NOT streaming 24-bit content from the SB3, but why tempt Mother nature?

We've got 6-Benchmark DAC1s in our studio facility. The volume control on it is definitely POST D/A conversion. We always use them in this config keeping any digital feeds going into it as close to full-scale as possible keeping the full 24-bit word as long as possible.

cliveb
2007-09-03, 15:19
ANY change to the 24-bit stream while still in the digital domain will change the bit-depth.
True.

And also true when using the Squeezebox's internal 24 bit DAC.

In other words, if you're happy to use the volume control with the SB's DAC, doing the same thing to an external DAC is no different.

Eric Seaberg
2007-09-03, 17:16
That's why I was recommending he NOT use the volume control on the SB3s digital out... are we talking about the same thing? It's not sounding like it.

I have mine fixed (full scale) feeding SPDIF to a Benchmark DAC and ONLY changing the volume on the Benchmark (which is after the D/A) if I need to trim the analog output.

Whatever... we answered his question at "YES!".

zapper
2007-09-03, 19:24
It is like the Wadia players/Dacs with their volume control in the digital domain. I have had Wadias, and the digital volume control works great, if the SB is the same, no problems.
Thanks Z

Skunk
2007-09-03, 19:48
It is like the Wadia players/Dacs with their volume control in the digital domain. I have had Wadias, and the digital volume control works great, if the SB is the same, no problems.
Thanks Z

Yes, but even Wadia suggests critical listening should be done with as little digital attenuation as possible, and unlike the Sb3 the player can be optimized for any system so that critical listening will be near the maximum volume*. The transporter has jumpers to perform a similar task, but the external attenuators I mentioned would/may be needed for a Squeezebox straight to power amp. Or, if you have a preamp you'd adjust it accordingly, so that you're at the upper end of the volume scale.

* http://www.wadia.com/technology/dvcontrl/sld013.htm

Skunk
2007-09-03, 20:01
ANY change to the 24-bit stream while still in the digital domain will change the bit-depth. I know you're probably NOT streaming 24-bit content from the SB3, but why tempt Mother nature?


Just for clarification, with 16 bit material, it's a 16 bit stream coming out of the Sb3 at full volume (with replay gain off), and changes to 24 only when using the volume feature.

As a side note, zapper, if your DAC is hdcd capable this bit shifting will keep the hdcd data from being decoded, even at 99/100 digital volume units.

cliveb
2007-09-04, 01:10
That's why I was recommending he NOT use the volume control on the SB3s digital out... are we talking about the same thing? It's not sounding like it.
I think perhaps we are talking at cross purposes. You appear to be recommending that the SB digital volume control always be set to max to avoid any possible increase in quantisation noise, and to use analogue volume control after the DAC (whether it be the SB's internal DAC or an external one). I understand and respect people's preference for that setup.

I was simply pointing out that the manner of operation of the SB's digital volume control is the same whether you're using the internal DAC or an external one. I happen to feel that a digital volume control done right (as the SB's is) works very well and is benign to the sound quality provided the basic gain staging in the analogue domain has been sorted correctly.

Bazile
2007-11-02, 20:26
Hi Folks;

I'm sorry to resurrect an old thread, but I'd like to make sure I'm using the SB3's volume right.

I'm using the coax digital out to an outboard DAC which sends the data to 2 headphone amps making 1 crude balanced headphone amp. Needless to say, trying to match 2 amp's volumes is a pain, so I've matched the 2 amp's volumes to be as loud as I ever want to listen when the SB's volume is at 100, then I use the SB for volume control. My DAC accepts 24 bits, and I'm listening to 16 bit CD's.

Set like this, my listening is always above 80 on the SB's volume. Is there a better way short of rematching both amp's volume for each song? Secondly, does anyone know at what point on the SB's volume the data drops below 16 bits? Thanks for the help.

Jeff

Skunk
2007-11-03, 06:53
Set like this, my listening is always above 80 on the SB's volume. Is there a better way short of rematching both amp's volume for each song? Secondly, does anyone know at what point on the SB's volume the data drops below 16 bits? Thanks for the help.

Jeff
That's the way to do it.

Last I heard the volume algorithm can attenuate 30 dB before affecting the data, which would be 40/100 on the volume scale.