[Ari33]

I had an old Audigy 2ZS which I recently replaced with a SB X-FI, (kindly given to me by a friend).
 
Initially I was very pleased with the results, well from the speakers at least.... Cleaner, smoother, sweeter and more dynamic.
However... I can't understand why my TF10 iems now do not sound half as good from my Pioneer seperate amps headphone out as they did when the amp was fed from my old Audigy 2ZS soundcard. Very weird! It has gone from TF10 bliss, near perfection to mediocre (XFI) and I now choose to no longer use the amp with my TF10's.   
 
From a technical perspective how is this possible? If the XFI has a different output impedance (I'm guessing) could it in turn affect the Pioneer amps own headphone out?  

 
 
Setup
 
Soundcard-  coax- Pioneer seperate amp to Speakers  and/or  Pioneer seperate amps own headphone out to TF10.

 

[cel4145]

Could be the Audigy had line level output and the X-Fi has a headphone amp in it--just a guess.

 

[Romanamon]

As far as I know a source's output impedance shouldn't affect the amp's. Since you're using RCA it should output a line out signal. Sounds like a mystery to me, perhaps a stray setting in the software. It could be that it just outputs a lower voltage line out, so it just sounds quieter at the same volume position on the pioneer.
 
Regardless, I'd be concerned using an iem from a headphone output of a speaker amp, because usually it will have a high output impedance, unless it has it's own dedicated headphone amp circuit built in.

 

[Ari33]

Could be the Audigy had line level output and the X-Fi has a headphone amp in it--just a guess.

 
Thanks cel4145, I wish that was the case but as far as I'm aware only the HD version of the XFI has a headphone amp section on the card.

 

[Ari33]

  As far as I know a source's output impedance shouldn't affect the amp's. Since you're using RCA it should output a line out signal. Sounds like a mystery to me, perhaps a stray setting in the software. It could be that it just outputs a lower voltage line out, so it just sounds quieter at the same volume position on the pioneer.
 
Regardless, I'd be concerned using an iem from a headphone output of a speaker amp, because usually it will have a high output impedance, unless it has it's own dedicated headphone amp circuit built in.

 
I have all the software features switched off so I know it's not that. A lower voltage is possible but no, it's far more severe than just a volume level difference.
 
I don't know what the Pioneer amps headphone out impedance is but simply judging from my ears it didn't show any issues with roll offs or frequency spikes unlike several other seperates amps I've tried (Onkyo, Kenwood etc). It adds nothing negative when paired with my DAPs  and sounds very good with the old Audigy 2 ZS...  but with the new XFI SB0770 it just sounds pretty average with the frequency response all over the shop.. and very grainy... and I can't understand why especially when the speakers still sound great from it.
 
The old 2 ZS didn't actually sound too bad through the speakers so I think I'll just re-install it for iem purposes and let the reasons why remain a mystery. 

 
 
Thanks for your input.