[DrSheep]

That's one short interconnect, very cute.

 

[miceblue]

miceblue: those frequency response variations are typical of high output impedance combined with non-flat impedance curve from the IEMs, which is very common with BA IEMs.

To avoid those variations (which distort the audio), you want to plug them into a headphone out with an output impedance that is lower than 1/8th the impedance of the IEMs. With your 32Ω Shures, that would be 32/8=4Ω.

Ah I see. The impedance response of balanced armatures do seem pretty funky after looking at some of the measurements from Innerfidelity. Do you know why this happens?

 

[fluidz]

Hey guys,
 
I recently bought a Fiio E12 to pair with Phonak Pfe232 iem's and an Htc One m7.  The e12 does a great job at expanding the soundstage of the 232's, brings the Mids more forward yet sadly diminishes the beautiful extended treble the 232's are known for.  Listening to Classical music with the E12 takes away the timbre of instruments and that pluck of a string all a sudden sounds compressed.  
 
The Fiio E12 does a good job at making the sound more enjoyable, but as I listen to music with lots of details I need something better.
 
So i've been looking at the C5D combo.  Has anybody had any experience with the Phonak pfe 232's and the C5D/C5? Is it a step in the right direction? 

 

[nuvestrahl]

Does anyone have experience pairing C5 with sensitive low impedance IEMs? I've been using DX50 with Fidue A83 IEM and while I really like the combo, the background hiss is quite noticeable at lower volumes and quiet parts in tracks. I was wondering if adding a C5 would clean up the sound since the same IEM has a completely black background from my desktop O2D.

 

[shuggs]

http://m.youtube.com/watch?v=pAgnJDJN4VA

Pretty much what it was designed for I believe...
"C5 is built for portable users who need a small amp with USB recharging, exceptionally low noise, sufficient output power, long battery life, and most importantly, a super fine volume control to handle sensitive headphones and IEMs."

 

[nuvestrahl]

Well, I suppose. But it's always better to hear from users than trust marketing talk. ^^

 

[ClieOS]

Just placed the order for some ultra short IC.

 

[jseaber]

  Well, I suppose. But it's always better to hear from users than trust marketing talk. ^^

 
Heh, I am personally responsible for every product specification and description. I wrote the C5 description in 2013 to convey the amplifier's intended usage. Around its Feb 2013 release, a few people assumed C5 would easily drive orthodynamics. The lengthy release article explained that was not a feasible goal for C5, but not everyone takes the time to read my essays. Hey, I understand. Who has time to find and read an engineer's 10 page product report? Anyway, I slightly revised the description after release to be as accurate and as concise at possible. Accurate claims keep people happy. Why disappoint?
 

Actually I have a question for @jseaber regarding amplifier designs. What design challenges are presented when trying to drive earphones with multiple balanced-armature drivers?
I've seen objective measurements done on portable media players with different in-ear earphones and the frequency response almost always turns out differently when driving an earphone with balanced armatures compared to one with dynamic drivers.

Here's one for example:.......

 

@miceblue: skamp is correct. Balanced armatures have particularly wide impedance fluctuations. Low output impedance is critical here. As with other highly efficient drivers, it's also important to minimize Noise.

 

[mandrake50]

   
Heh, I am personally responsible for every product specification and description. I wrote the C5 description in 2013 to convey the amplifier's intended usage. Around its Feb 2013 release, a few people assumed C5 would easily drive orthodynamics. The lengthy release article explained that was not a feasible goal for C5, but not everyone takes the time to read my essays. Hey, I understand. Who has time to find and read an engineer's 10 page product report? Anyway, I slightly revised the description after release to be as accurate and as concise at possible. Accurate claims keep people happy. Why disappoint?
 
@miceblue: skamp is correct. Balanced armatures have particularly wide impedance fluctuations. Low output impedance is critical here. As with other highly efficient drivers, it's also important to minimize Noise.

 Interesting. I use my C5D with both the Hifiman 400 and 400i. Now I don't sit and seriously pick apart the sound, this is for "sort of" portable use around the house and yard. The C5D seems to do a quite adequate, if not very good job in that role. Of course, both the 400 and 400i are considered to be relatively easy to drive for planars.  If we are talking HE 6, I can see why you would say it may be a no go.

 

[ThurstonX]

   Interesting. I use my C5D with both the Hifiman 400 and 400i. Now I don't sit and seriously pick apart the sound, this is for "sort of" portable use around the house and yard. The C5D seems to do a quite adequate, if not very good job in that role. Of course, both the 400 and 400i are considered to be relatively easy to drive for planars.  If we are talking HE 6, I can see why you would say it may be a no go.

 
+1, adding my ~34-ohm HE-500s to the list.  Like you, not picking apart the sound, but in occasional sessions I'm always pleased with my C5.  Usually it's from a Rockbox'd iPod Classic, which has a nice DAC.  With the HE-560s OTOH, no way, but then they're right around 50 ohms and consistently take my Lyr to noon and beyond on the volume knob.

 

[Fungus]

It's unfortunate that when the my c5 is set on max on high gain, the treble distort quite badly. 
It clear stuggles to drive my hd25 with a sensitivity of 120dB to high volumes. 

 

[miceblue]

It's unfortunate that when the my c5 is set on max on high gain, the treble distort quite badly. 
It clear stuggles to drive my hd25 with a sensitivity of 120dB to high volumes. 

Innerfidelity measured the HD25-II to require 0.04 mW of power to reach 90 dB SPL at 74 ohms. The C5 should have absolutely no problem driving that. From here, the C5 outputs about 60 mW of power at 62 ohms.

Why are you setting the volume level to maximum on high gain anyway? Are you purposely trying to make yourself deaf? o.0

 

[Fungus]

Innerfidelity measured the HD25-II to require 0.04 mW of power to reach 90 dB SPL at 74 ohms. The C5 should have absolutely no problem driving that. From here, the C5 outputs about 60 mW of power at 62 ohms.

Why are you setting the volume level to maximum on high gain anyway? Are you purposely trying to make yourself deaf? o.0

No, they are at 600 ohm but the sensitivity is 120 dB which should be very efficient. 
On max setting, I find some tracks aren't loud enough particular even in a noise free environment.
It's only about 20% louder than playing directly off my phone.  
I guess the c5 doesn't provide a whole lot more voltage than most standard daps. 

 

[miceblue]

Innerfidelity measured the HD25-II to require 0.04 mW of power to reach 90 dB SPL at 74 ohms. The C5 should have absolutely no problem driving that. From here, the C5 outputs about 60 mW of power at 62 ohms.


Why are you setting the volume level to maximum on high gain anyway? Are you purposely trying to make yourself deaf? o.0

No, they are at 600 ohm but the sensitivity is 120 dB which should be very efficient. 
On max setting, I find some tracks aren't loud enough particular even in a noise free environment.
It's only about 20% louder than playing directly off my phone.  
I guess the c5 doesn't provide a whole lot more voltage than most standard daps. 

That is very strange.

The C5 drives my 669-ohm AKG K240 Monitor just fine even with DR18 music, and the K240 M is rated at 88 dB/mW of power. I think it's pretty much impossible to have a headphone with a sensitivity value of 120 db/mW as even in-ear earphones don't accomplish that to my knowledge. I certainly have PLENTY of volume left to spare on the C5 with the iPhone line out (as in I get plenty of volume at volume level 11/63 with low gain) compared to straight out of my iPhone, which basically runs at >50% volume.

What's your source/DAC? Maybe it doesn't produce enough voltage for the C5 to amplify.

 

[Fungus]

That is very strange.

The C5 drives my 669-ohm AKG K240 Monitor just fine even with DR18 music, and the K240 M is rated at 88 dB/mW of power. I think it's pretty much impossible to have a headphone with a sensitivity value of 120 db/mW as even in-ear earphones don't accomplish that to my knowledge. I certainly have PLENTY of volume left to spare on the C5 with the iPhone line out (as in I get plenty of volume at volume level 11/63 with low gain) compared to straight out of my iPhone, which basically runs at >50% volume.

What's your source/DAC? Maybe it doesn't produce enough voltage for the C5 to amplify.

I double checked and the hd25 definitely have a sensitivity value of 120dB.