[tothemax]

 First let me start out by saying that I know that the UH-4 is a amp/dac combo. That said, I don't know enough about how to read the specs of each unit to make an informed decision. Looking at the summary's  they both have digital volume control, bass boost
( C5 +6.5db@ 80 Hz) ( UH-4 2x gain select). The UH-4 has a X feed w/bypass. The UH-4 list( 16bit/48kHz dig audio, I assume thats
the dac). The C5 has a feq. response of +/- of 0.02 db were as the UH-4 feq. response is 13 Hz to 22.5 kHz +0/1 db.
Output impedance for the C5 is 2.2 ohms, the UH-4 OP impedance is 0.4 ohms.
This were the C5 Specs start to list max output in ohms Vs. VRMS. 600 ohms @ 4.146 VRMS 150 ohms @ 3.337 VRMS, 32 Ohms
@ 1.010VRMS. The C5 lists THD + N as 20-20 Hz at 150 ohms 0.0009%, 32 ohms at 45%.
 
 
 
 
 
 
  
 

 

[kimvictor]

Although I have not heard UHA-4 or C-5, reading from spec, UHA-4 would probably be better with IEMs than C5 would be. 
Can you tell me
1. What your application is (iem or hp)
2. What kind of sound you want(you can change the sound on UHA-4 through op-amp rolling)
3. How much would you care for battery and portability?

 

[D K A]

I own the JDS Labs C5 and i really love it
The bass boost just amazing, it gives the right amount and didn't mess up the music
I think you better try them first if you can

 

[tothemax]

Being portable would be important. I will be using hp not iem.

 

[kimvictor]

For portable use, I say UHA-4. Leckerton is simply a joy to order from. UHA-4 are much smaller than C5 and has more battery life, and a DAC, making it usable with computers as well.

 

[tothemax]

Thanks for the advice