[headfone]

I'm sure there is a posting (= obvious answer) on this topic somewhere (other than this thread) ... so apologies in advance for any redundancy.

When plugging IEMs into certain NON-portable amps -- e.g., PPA2, Meier Corda -- I've noticed a "default" hiss (i.e., hiss at minimal volume ... nothing playing) that varies from negligible (Headroom Little) to intolerable (PPA2).

I've noted this in both Shure IEMs I own. I do not hear it in full-sized cans: Senn 650, AKG 701, Grado 325i, etc.

Also, I don't hear hiss on all portable head amps I've used (Xin, Go-vibe) or straight out of 'phones jack ofn portable players.

In your experience or best guess, what's the source(s): Impedance, Sens, combination of these, etc.?

Shure SE530 relevant specs:
Sensitivity (1mW): 119 dB SPL/mW
Impedance (1kHz): 36 ohm

Full-sized cans have higher impedance, but not sure what sens. metrics are.

 

[FallenAngel]

High current Class-A discrete buffers in the PPAv2 matched with insanely sensitive (119 db SPL) headphones = hiss. Maybe turn down the gain on the PPAv2 or easier yet, use a resistor adapter on the output.

 

[headfone]

FallenAngel:
This topic was reposted in DIY sub-forum:
http://www.head-fi.org/forums/f6/iem-hiss-ppa2-392233/
I think your "resistor adapter" tip was addressed by 2.2R --> 3.3R mod suggested there.

 

[shigzeo]

a resistor will help but probably not overcome the home amp. 119db is way too sensitive to manufacture an iem. it will reveal hiss in any source, portable or home. my westone i think were 118db and i heard hiss from every source but one: my m-audio transit (and even then i was not sure).

manufacturers are starting to tone down their insanely sensitive phones finally and the consumer is able to hear more music and less fuzz.

 

[headfone]

Quote:

Originally Posted by shigzeo /img/forum/go_quote.gif a resistor will help but probably not overcome the home amp. 119db is way too sensitive to manufacture an iem. it will reveal hiss in any source, portable or home. my westone i think were 118db and i heard hiss from every source but one: my m-audio transit (and even then i was not sure). manufacturers are starting to tone down their insanely sensitive phones finally and the consumer is able to hear more music and less fuzz.

Do manufs make ultra-sens. 'phones because they think most users will pair them up with wimpy (un-amped) sources, like the crappy Headphone Out Jack of an iPod?
I agree that no cans need to be this sens.
With SE530s, I recently had a disquieting experience: an experimental CDP lost its clock signal, generating a sudden burst of crackling and pink noise. The amp was on low-moderate volume but the SE530s made the burst sound like a cannon!

 

[shigzeo]

well, im afraid the ipod alone is not to blame. since basically early nineties, portable manufacturers have found it better to appease the masses with low price than quality as too few really care about sound.

ipod is currently probably among top tier for output from headphone for portables but of course is not anywhere near the quality of a dedicated amp.

i think the are super sensitive from originating as monitors for stage musicians who need them to pump out 100db from wireless mics. they are powerfully amped but they need to ensure the musician can hear everything from one ear or both ears in use.

only recently has that attitude changed and iem manufacturers are making them for the casual and more intrepid listener.

 

[kaushama]

I can't stand the hiss out of my TF10. I am going to try good DR. Xin's option of having add resistance to IEMs. I have a supermini.

 

[shigzeo]

haha, yeah my um2 hissed too much with portables, home amps and portable amps. i did not have a good resistor cable then. im sure it would have helped