The iPod volume control does affect the volume coming out of the iStreamer. By default, it's at the top, so the iStreamer puts out a 2.25 volt signal. But if you need a weaker signal going into your amp, it's great that you can reduce the volume.
At work, my current headphone amp is a portable and the 2.25 volt signal is too strong, causing distortion. Turning down the iStreamer volume a touch eliminates the distortion and the sound is great.
At home, in the bedroom, my integrated amp is 50 watts and my speakers are sensitive (92 dB). If I'm listening very quietly at night, the only way to get the sound quiet enough is to turn down the iStreamer volume.
The iPod is probably just sending a signal to the iStreamer to attenuate the analog output signal. Since the iPod is sending the iStreamer raw data, you can't reduce the "volume" of that data. But you can send extra info along with the data to control the volume once it's been converted into analog sound. It must work that way somehow.
Quote:
Originally Posted by
Brent Hutto 
So was the final verdict that the iPod volume control does or does not affect the volume of the sound coming out of the iStreamer?
Because number one, that is a pain in the butt. I hate, hate, hate multiple volume controls. I want to set the volume on the headphone amp and not have it get screwed up because I touched the click wheel wrong. Total showstopper if that's how the iStreamer works.
But number two, how in the world can the iPod volume control be changing the raw bitstream supposedly being sent to the iStreamer?
I guess I just don't understand how iPods work but shouldn't the volume control operate downstream of the A/D converter in the iPod? Otherwise why wouldn't the volume control also affect the volume when using a regular LOD?