All,
The Apple Dac chip appears to have an integrated push-pull output stage built into it. It runs on +/- voltage rails, so this is why they don't use coupling caps after the dac... there is no dc offset voltage to block.
So picture a dac + opamp output stage (for both the line-out and headphone output) all in one chip.
This approach is cleaner than the previous iPods line outs and headphone outs (except for the headphone out of the 1st gen shuffle, which is reported to have the same sort of design).
From what I am hearing with my 6G -- Compared to the line out of the stock 4G, 5G, and 5.5G units, the line-out of the 6G is certainly
closer to that of the 5.5G iMod using the ALO iMod dock cable... black gates), ... but do I believe once people do the comparions between the iMod and the line out of the 6G, you'll hear where the line out of the 6G falls short. Its a little thinner sounding and not quite as warm. When you use the Vcap dock with the 5G/5.5G iMod, it is even easier to hear the gap in performance between them.
I see on the ALO website that Ken just put up a package deal... the 80GB 5.5G iMod + iMod Dock cable for $575. This is very sweet package deal, and I'm sure he'll do something similar with the Vcap docks.
If your priority is getting the very best sound, the 5.5G iMod is the way to go. If your priority is getting 160GB, the 6G offers that, but...
... speaking of 160GB, the drive in the 160GB iPod is the Toshiba MK1626GCB. Does anyone know where these can be purchased online? I like to try it in my 80GB 5.5G iMod, just to verify it will work because there is growing interest in having this done. I can try calling Toshiba on Monday, but I doubt they will sell in small quantities
Best regards,
Vinnie