Hello, I have received a 4g imod from Ken at ALO. I am very happy with the sq of this unit. I can plug in my Senn HD600s' to the headphone input and get decent volume from them. I thought that this was disabled and could only be used with a headphone that had a volume control. As I stated the sq is pretty good, I would not think that the imod could power the 600s'. Could anyone please clarify this for me.
Thanks
Hi cpk,
Welcome to audiocircle and the RWA forum!
With the 4g iMods, the headphone jack has been converted to a modifed line-out. This means that you won't be able to control the volume... it is a fixed 1Vrms output. I don't recommend connecting headphones directly to this jack. You really should use a headphone amp (with built-in volume control) to drive the low impedance of headphones, and so you can raise/lower the volume.
What you are doing now is kind of equivalent to using an RCA to female 1/8" stereo jack converter cable and plugging this into a home audio CD player. Sure, you'll get sound out of your headphones, but the line-out stage is really designed to drive a higher impedance load... a headphone amp or home audio preamp/intergrated amp.
If you have any other questions, please let me know.
Enjoy your iMod!

Vinnie