The Fuze has several parallel outputs. The headphone amplifier is separate from the outputs available at the 30 pin connector.
Once the Fuze is docked, the headphone output is disabled, and audio feeds through the output at the 30 pin connector.
I’ll share a wee bit of enlightening information here. SanDisk has employed two output schemes (“scheme” in the engineer’s terms, not a “cloak and dagger” situation of course) for the output when docked.
The fur was flying a while ago, regarding “true” line out versus the implementation on the Sansa. Some prefer to have a line output that is at maximum, without any modification. Perish the thought of a gain stage in the way!
SanDisk released the e200v2 device early this year, with the same chipset as the subsequently released Sansa Fuze. The v2 was a handy testbed for the new machine. On the e200v2 device, when docked, the headphone amplifier is squelched, and the 30 pin connector gets audio at 100 per cent. Once lifted from the cradle, the headphone is once again active. The headphone output is different from the audio at the 30 pin connector, in that it’s a 60mw output optimized for the wee 16 ohm earbud.
When undocked, volume level is resumed via the handy scroll wheel, starting at the last setting used.
On the Sansa Fuze, this 30 pin output is not fixed, but variable via the scroll wheel. Some complain that this is sacrilege, thinking in purely analog terms, that the audio is making a circuitous path through a rheostat, the scroll wheel. Well, the wheel is actually no more than a key command, as far as the processor is concerned. The audio signal is just as pure as it would be if the gain were defaulted to maximum.
If I plop the Fuze in the dock, having the output variable is preferable, as one can adjust the volume while observing video on the screen, or making a quick trim to the volume level. One might be thinking in terms of using up power when the volume is rolled up towards maximum, but this is a higher impedance situation than a headphone speaker.
Running a set of decent harmon/kardon badged coomputer speakers with both devices, and swapping the 3.5mm headphone plug into the dock output, or the headphone output, I can assure you that we are indeed listening to a different gain stage than the headphone output. There’s a tasty signal available at the 30 pin port.
Both schemes have their advantages, using the e200v2 or Fuze, when docked. The volume setting is preserved for undocked operation with your headphones in either device.
As for the sound quality, both are superb.