Just a few thoughts as I'm a passive guy ... your impedance's are fine as Al has confirmed but we don't know anything about the V/out of the source and your V/in of the amp
Because you've eliminated the ... Pre which usually takes the responsibility of driving the IC to the amp ... your source is now the driving everything
I think the IC between the Passive's output and the amp's input is much more critical than the Digital vs Analog volume control debate
The IC from your passive attenuator should be very low in capacitance and as short as possible to keep from rolling off the highs ... Al can expound on this and the V/out V/in through the passive
On the digital vs analog volume control debate ... all volume control/attenuators sound best at full volume as they have little or no resistance in the circuit to degrade the sound when set to FULL
If a digital volume controls throws away bits and compromises the sound ... then I say a analogue volume controls have to many resistors or resistance in the circuit at low volume to attenuate the volume and compromises the sound equally ... 6 of one a half dozen of another
I cheat ... after my source I use a Burson class A no neg feedback buffer feeding the volume controls in my Phase Linear D500 to do the driving
The P/Linear's volume controls are a compromise but I also have a modded P/L D500 which I've bypassed the V/Controls on and will be using a Slagle auto former set up that I'm just finishing up
The Slagle A/F doesn't suffer the bit drop out of the digital V/C or the resistance issues of a typical resistor based passive V/control and it does a better job of shifting less as you turn the V/C up or down
Something not mentioned or considered is the shift in impedance as the V/C is turned up and down and again Al can easily explain this better than I
Because you've eliminated the ... Pre which usually takes the responsibility of driving the IC to the amp ... your source is now the driving everything
I think the IC between the Passive's output and the amp's input is much more critical than the Digital vs Analog volume control debate
The IC from your passive attenuator should be very low in capacitance and as short as possible to keep from rolling off the highs ... Al can expound on this and the V/out V/in through the passive
On the digital vs analog volume control debate ... all volume control/attenuators sound best at full volume as they have little or no resistance in the circuit to degrade the sound when set to FULL
If a digital volume controls throws away bits and compromises the sound ... then I say a analogue volume controls have to many resistors or resistance in the circuit at low volume to attenuate the volume and compromises the sound equally ... 6 of one a half dozen of another
I cheat ... after my source I use a Burson class A no neg feedback buffer feeding the volume controls in my Phase Linear D500 to do the driving
The P/Linear's volume controls are a compromise but I also have a modded P/L D500 which I've bypassed the V/Controls on and will be using a Slagle auto former set up that I'm just finishing up
The Slagle A/F doesn't suffer the bit drop out of the digital V/C or the resistance issues of a typical resistor based passive V/control and it does a better job of shifting less as you turn the V/C up or down
Something not mentioned or considered is the shift in impedance as the V/C is turned up and down and again Al can easily explain this better than I