Because going through a 2nd A2D-D2A conversion is preferred? There are no free lunches here and a device that doesn't show noise under normal operating conditions has chosen the correct approach which is also less complex.
One example of what is possibly a defective PS does not prove the rule. You can have your opinion but it's a limited view as you seem unwilling to accept other's conflicting experiences or topology discussions. Amp stages always run at a fixed gain and the DX90's is not excessively high. Putting an additional and required dig or analog V control in front of it doesn't change that and you certainly can't put it after. Your argument isn't sound, IMO.
You're worried about induced noise of a unique PS but advocate a noise inducing and effectively compressing circuit like crossfade. Where in the circuit of your favored Arrow do you think the analog V control resides?
I have just mentioned "Listening is Believing" in my previous post. Taking out my noise IPAD 4 PS, and just running the DX90 in battery mode with the Arrow 4G and with crossfeed level 1 turned on, I can experience better noise/instrument separation/sound stage with my combo
I have repeatedly state the setup and conditions where my impression comes from: Using Yamaha EPH-100 and PK1 clone with my DX90 (max LO volume) + Arrow 4G, comparing to the same phones with just the DX90 with volume set at volume 160. These is my setup and my impression. And I believe my setup are quite common (judging from other portable DAP threads) and so I would like to share my view.
You are free to say "No one listens to the DX90 internal amp at volume 160, I never listen below volume 225...", or "The Arrow 4G is noisy as hell at high volume/gain setting...". Because that will be your setup and you are free to give those impression using difference setup. If the other readers use similar setup then they will learn from you.
It is also the exact low noise floor and expanded soundstage of my "DX90 + Arrow G4" allowing me to enable your so call "noise inducing and compressing circuit" of crossfeed. The crossfeed is for "correcting" the soundstage to me. Please don't hijack 1 sentence in my post and try misleading other readers that I use crossfeed to lower noise.
Edited by borrego - 5/14/14 at 8:12pm