[ishtob]

i got a low impedance headphone: k518dj's, would adding a 150ohm-220ohm vishay precision resistor make it sound better?

or more importantly help make it sound better on a amp?

 

[el_matt0]

im not 100% familiar with adding inline resitance to headphones or to an output stage of an amp (end result would be the same i believe). but totally off the top of my head i think 150-220ohms sounds a touch high...usually i think resistance in that range is added more so to give you a better range of control on your potentiometer. ie. for low impedence headphones, if the range it takes to go from no volume to "max listening volume" is say from the 12oclock position on the pot knob, to say the 4 oclock position, adding something in the range of 150-200 ohms i believe would probably increase that range from 12 to say 7 or 8 oclock. basically it will let u have more "control" over the volume via ur potentiometer in a sense...however i know that adding in such a high amount of resistance can degrade the sound quality as well. most often when people want to "sweeten" up the sound by adding in line resistance its generally in the range of like 10-30 ohms i think. and i believe carbon film (not metal film or carbon composite) resistors would be what you would want to try to use. kiwame or riken are a couple of well reputed names...

 

[ishtob]

I think I read somewhere that metal-film should be used in the audio pathways, at least inside a cmoy amp... I tried a 75ohm metal-film resistor, it didnt degrade the sound much, just lower the volume a bit.

 

[aych]

metal is more prescise, carbon is warmer. imo.. i dont find it makes too much difference unless you're really hissing, then a smaller 32ohm or so will help it.

 

[ishtob]

oh, okay, I'll try both with alligator clips and see which one I like better.

edit: and no, there's no hissing, just want to see if adding resister would make the headphone sound more to my liking.

 

[aych]

doubt resistors will do too much except for a bit of tonal change .

 

[amb]

If your headphone's impedance curve is not ruler-flat with respect to frequency (and most aren't), adding series resistors will introduce frequency response aberrations because the resistor will form a voltage divider with the headphone voice coil, and since the voice coil impedance isn't linear, the resultant attenuation will be uneven across the frequency band.

 

[Peyotero]

I was intrigued by the same question so i bought from some head-fier a 75ohm adaptor for my Koss Portapro's (60ohm). I'm still trying to figure out what's it good for..

So, either the capsitors that were used are low quality or I'm just trying to hard.
I bought this thing after reading the bloke at Moon Audio practically swear by it and many other head-fier saying that adding the resistors to the portapro's/ksc75/ksc35 is absolutly vital.
The purpose is suposedly "better bass control", but I just hear everything toned down after i plug the resistor.

Maybe I'm doing something wrong. I dunno.

 

[mark10001]

It could change the frequency response of the amp, but how much depends on the design of the amp. For an example see my LT spice simulation file and change the output resistance.

Head-HIFI.com - Headphone Amplifiers

 

[Peyotero]

Ok. Looks like it's more complicated then i thought. I just did a little test plugging my phones with and without the 75ohm adapter to my vintage Sharewood reciever. Not only i couldn't notice the tonal differences but even the volume didn't went down.. This is contrary to my prior "observation" with my silly arse Sandisk Sansa Express flash DAP where the volume was cut down significantly and the music sounded a bit muffled when i plugged the adapter.
Could this be due to the flash DAP having a hard time driving my cans with the added ohm resistors and the reciever barely noticing them?

In conclusion, the only decent advice I could give, since it appears i know nothing about audio and electronics, don't do a perament mod like adding resistors to the cable itself. Buy/build an adapter and play with it. Couse it looks like not every source/amp is gonna like the extra ohms.