1.2k is in balanced mode. 600 ohm in SE.
Why the desire to use passive volume control ?
Balanced or SE ?
You will need an amp with an input sensitivity of around 1V (SE) and 2V balanced.
The output resistance is part of the passive post filter and essential for the muting circuit it seems.
I would assume the output resistance is ohmic.
This means a load above 10k will be fine but you will loose some output level (about -1dB).
Both the load the Ares 'sees' will vary depending on the volume control as well as the 'new' output resistance of a passive volume control will vary depending on the volume setting.
How this will work out depends on the Length (capacitance) of the used cable and power amp.
Why not direct it directly and use digital volume control ?
Or use a 'normal' pre-amp ? I mean the power amp is also an amplifier. Why would adding buffer or few times gain amp be such a horrid ?
Thanks - very useful! So, a 10k passive volume control will be suitable between the Ares II and a Hypex power amp.
My interest in using passive volume control is because I was thinking of getting a balanced power amp (e.g. Hypex) to go with this DAC, but I don't already have a balanced active preamp (they seem quite expensive), and it I don't think I need the gain. I also read some people prefer passive preamps (assuming it all works). Yes a unity-gain buffer with volume control would be of interest to me.
I'm using Spotify on a tablet as a USB source - is there a way to do digital volume control in Spotify? That would certainly solve it - Then I could connect the Ares II directly to the power amp.