Use of Preamp versus Digital Volume from Computer


Has anyone done a direct comparison of using a high quality preamp in a computer audio setup to control volume from DAC to the amp, versus going straight from DAC to amp and using the computer to attenuate volume via the playback software?

Not necessarily looking for speculation or general opinion as there's plenty of that to go around, just feedback from those that have compared or have true knowledge of the pros/cons.

I've had 3 different computers and 4 different DACs over the past year or so, where I've used Itunes to control volume (feeding an Empirical Audio Turbo-3). Nothing really for me to complain about as far as sound. I've heard that the Turbo-3 (by way of converting 16 bit to 24 bit) actually helps the quality of the digital volume attenuation.

My system is fairly resolving with the Turbo-3, Isabellina DAC, modded Rogue Stereo 90 tube amp and Living Voice IBX-R2 speakers all fed via either an IMac or Macbook from Itunes.

It's a stupid question for me to pose personally since it's a bit of "if it's not broken, don't fix it". My system sounds fine to me for redbook playback. But curious how much alteration the digital volume control is doing to the digital feed from the computer to the DAC (or in my case the Turbo-3).

Thanks,

Marc
mb9061

Showing 1 response by mb9061

Thanks Herman.

I'd heard some time back that Itunes versions 7 and up had dithered volume control that was quite good versus truncated 16 bit volume that was found in earlier versions (Benchmark's website has a write-up on it for example).

I can't tell any loss in sound quality with using Itunes to control the volume and most my listening is done with the volume at 10-30% of max, controlled via an IPod Touch with the remote app. But I see lots of people saying to set it at a full 100% and go with analog attenuation (which I tried via several different integrated amps and didn't really care for).