[meowmix4jo]

Has anyone tried upgrading capacitors on the E9? I have 47µf and 470µf on hand but not the rest, not sure if it would be worth it.

 

[mark2410]

oooh, if i recall there was a thread one here sometime back where people were modding the E9.  im afraid i cant recall what it was called but maybe have a google and see if it comes up

 

[Jason Bourne]

Is anyone using this as a headphone amp with a Audio Technica LP120 turntable? The turntable has a preamp line out but Im hearing some crackling here and there through my headphone's (Beyerdynamic DT 990) listening to this setup... just wondering if anyone has experience with the exact setup and what your experience has been. Would I gain any benefit by adding a E17 to this setup?

 

[techpicky]

I just saw this now ancient post.  I too have a FiiO E09, and a pair of Yamaha YH-2 headphones. Based on your post I dug my "Vintage" Yamaha cans out of the closet and once again tried them with the E09.  You might want to consider a far less radical approach to portable audio, and invest in some newer headphones that are both better and far more sensitive.
 
I bought the Yamaha headphones new back in the very early 1980s when I was working at a HiFi audio store.  I bought them even then because they were affordable, but even then not the best.  I just listened to them today, and yeah, there is a good reason they live in a box in the closet.  They don't sound especially good and they are fairly high impedance and inefficient so they require considerably higher Voltage swing than most headphone outputs.  I had a pair way back then too on my bench when I was doing audio service.  I had to drop the resistance of the series resistors to the headphone jack on my bench receiver just to use them. 
 
Today they are not really that great.  The E09 will drive them modestly well, but could still use more level (that is saying a lot given the E09 can drive just about anything).  I compared them to my Sennheiser HD-595s. The old Yamaha phones were a bit more bass heavy, but overall the HD-595s just blow away the Yamaha phones.  The HD-595s are far more open and airy with far superior imaging.  The bass on the HD-595s is also much tighter.  Overall the Yamaha YH-2 phones sound squashed and muddy.  My Ety ER4Ps are better too, and most definitely more portable as well. 
 
So, with another set of phones you could definitely get better sound quality, and likely drive them directly from your iPod shown.  As least use something more portable friendly, such as the FiiO E17.
 
As for the modifications to the E09, I would assert that most of them are not necessary.  The coupling capacitors and other capacitors that really impact audio quality are already ELNA RVO capacitors in the FiiO E09.  The power supply caps are really just fine as is.  Any changes the capacitors would make would be far too subtle to really be able to hear on the Yamaha phones anyway.
 
You might want to consider listening some headphones.  I realize that after a while you get "used" to the sound of a set of headphones or speakers.  Still, it will only take a few hours or less of listening to some newer, and I would say far better headphones to move on from those "vintage" cans.  You can leave the big box and the extra box of batteries behind too.