[ibis99]

Any suggestions. Main phones are ER4s and UM3x.


Thanks

 

[shigzeo]

Do you mean portable amp? Or DAC? Are you interested primarily in size, or in performance, or both? 

 

[proton007]

No point unless you want to use headphones.

 

[Il Mostro]

HP-P1 or CLAS + your favorite amp.

 

[shigzeo]

I find the iPad a bit bulky to be considered portable anyway, but my commutes are done standing in someone's armpit and then changing to another train and standing with someone in my armpit. 
 
If you want a desktop system and you are bound and determined to use an amp/DAC, there are myriad choices. The HP1-P1 I've not used, but I assume it's pretty much the same as the Cypher Labs Solo outboard DAC. To be honest, the iPad by itself has a decent sound, one that is competent and in some cases, better than some amps out there. 
 
You'll have to go somewhat high up the ladder (quality, not necessarily price) to better it. For hard to drive earphones, a simple iBasso T3D would drive better than the iPad will naked, but will have a bit more background noise. A cheap Line Out Cable and a cheap, but good amp will do the trick for about 150$, or thereabouts. You can go all the way up, and do a HP-P1 or CLAS and amp of your choice, too, and only probably enjoy the thing more, but be tied to a desk or bedside.
 
big big big.
 
EDIT: As for outboard DAC's, you can use almost anything that has battery power. I've used dozens of DACs with the iPad, some as cheap as 150$, some as expensive as 1500$. As long as the mains or battery is powering the DAC, no problem. The latest I've used and really really like is the ~300-400$ GoVibe VestAmp+.

 

[ibis99]

​

I prefer something small amp wise. I was thinking RS P-51 Mustang.

As stated in the original post I'm using either ER4s or UM3x.

 

[proton007]

Repeat: no point if you use easy to drive earphones.

 

[meyerovb]

Quote:

Repeat: no point if you use easy to drive earphones.

So with high end custom IEMs, like say the Heir Audio 4.A, neither an external DAC or external AMP will give you any improvement in sound quality when using an iPhone or iPad?  I don't need higher volume, I don't want to go deaf.

 

[proton007]

What do you define 'quality' as ? 
If you just feel you are not getting the best out of your earphones, its just your preconceived notion. The earphones and audio is already working to its best in the audible range.
The differences in DACs are so minute you wont be able to feel anything except mental satisfaction after spending 5-800 bucks.
External amps, same story, most of them are solid state. Tube amps change the sound, but they're not portable.
Amps make a difference only if there is a load mismatch, when the source is not able to drive the load due to lack of power. For example the Shure SE425 SPL is 109dB/mW. For a desired 110 dB SPL for most music, it needs antilog((110-109)/10) = 1.25 mW. The Sennheiser HD800 on the other hand, needs 6mW to reach the same level, and the HD650,  20mW, hence the need of an amp.
Although hard to estimate the iPhone/iPad power, they are more than capable of driving 32 Ohms.
I hope this clears things.

 

[ibis99]

Proton007-

So you consider the ER4s to be a " easy to drive headphone" from a portable source like the iPad?

 

[proton007]

 
Quote:

Proton007-
So you consider the ER4s to be a " easy to drive headphone" from a portable source like the iPad?

Depends on the impedance, from their website they have two impedances available: 27 Ohms and 100 ohms. 
Figure which one is portable based on the calculations above.