pre-amp, passive or active?

[olds1959special]

I have a switch on my pre-amp to toggle between passive and active. With my current dac, and keeping cables as short as possible, I'm thinking maybe I prefer the passive mode more. My dac is outputting 2 volts and is connected by a 0.5 ft Mogami 2964 cable to my pre-amp, which is connected to my Halfer amps by a pair of solid silver conductor IC's that are 2 ft each. 

Active mode sounds fuller, brighter, but adds a little harshness.

Edited April 13 by olds1959special

[Holmz]

My understanding is that as the output gets lower the output impedance gets lower.
So at “full tilt” the passive should be great.

Do you find that at low output volume that the active is different, more so than at higher volume?

[olds1959special]

1 hour ago, Holmz said:

My understanding is that as the output gets lower the output impedance gets lower.
So at “full tilt” the passive should be great.

Do you find that at low output volume that the active is different, more so than at higher volume?

The active is the same at all volumes, it just boosts the level slightly and adds a little brightness.

After some experimenting I've found I prefer it on. At least with my current source, which outputs 2.6V? For some reason I think my optical output of my Apple TV is lower than nominal? So I don't know what it's outputting without measuring.

As I understand it, the pre-amp active mode helps with impedance matching.

Edited April 17 by olds1959special