[twister6]

  As far as I know, the UE adapter is indeed just a 100ohm adapter and nothing more (*not a voltage divider). So basically you just added 100ohm more to the AP100's output impedance.

 
Thank you ClieOS!!!
 
I wonder if they would have something similar to this: http://www.ebay.com/itm/Impedance-Adapter-Plug-75-ohms-3-5mm-to-1-4-inch-plug-/251464612918?pt=US_Cables_Snakes_Interconnects&hash=item3a8c757c36 but with 3.5mm connector.  I think 75ohm might work as good as 100ohm, just need 3.5mm plug...
 
... nevermind, found Ety's adapter where you can select different impedance option: http://www.ebay.com/itm/Etymotic-ER4P-to-ER4S-3-5MM-plug-resistor-adaptor-/281276949691?pt=US_MP3_Player_Cables_Adapters&hash=item417d69a4bb

 

[zagtastic]

i recently discovered and read this entire thread with great interest, however i still have a question:
 
is there still no way to obtain a (faux) impedance decreasing adapter commercially?  i have a CL theorem 720 dac and really want to use it with DN-1000 phones, but the noise floor is distracting.  i would very much love a portable, <$100 solution that allowed me to pair these without affecting SQ.  unfortunately i'm a computer guy but not an electronics guy and don't think the DIY option will work for me.  thanks much in advance.
 
basically, i was hoping that in the last 6 years a reputable company would have made the same thing as WiR3D, as i could really use one

 

[twister6]

  i recently discovered and read this entire thread with great interest, however i still have a question:
 
is there still no way to obtain a (faux) impedance decreasing adapter commercially?  i have a CL theorem 720 dac and really want to use it with DN-1000 phones, but the noise floor is distracting.  i would very much love a portable, <$100 solution that allowed me to pair these without affecting SQ.  unfortunately i'm a computer guy but not an electronics guy and don't think the DIY option will work for me.  thanks much in advance.

Why not get something like this for $14, in either 75ohm or 150ohm flavor? http://penonaudio.com/3.5mm-Inpedance-Plug
 
Noise floor comes from high sensitivity headphones driven by high level power source.  My temp solution of driving Zero Audio Doppios from AP100 DAP is with 100ohm UE adapter (came bundled with UE900 headphones), but I'm waiting to receive these impedance adapter from penonaudio now since it's a cleaner solution.
 
Is that what you are looking for?

 

[zagtastic]

 
Why not get something like this for $14, in either 75ohm or 150ohm flavor? http://penonaudio.com/3.5mm-Inpedance-Plug
 
Noise floor comes from high sensitivity headphones driven by high level power source.  My temp solution of driving Zero Audio Doppios from AP100 DAP is with 100ohm UE adapter (came bundled with UE900 headphones), but I'm waiting to receive these impedance adapter from penonaudio now since it's a cleaner solution.
 
Is that what you are looking for?

 
appreciate it twister, but based on what i have read here and other places (including: http://www.innerfidelity.com/content/meridian-explorer-case-study-effects-output-impedance), the effect of such an adapter would be expected to be a reduction in sound quality.  unless i'm missing something, that adapter will raise the apparent impedance of the output as seen by the headphones which will result in at least some amount of coloration and muddying of the sound as well as a decrease in the damping effect.  if that's the case, i may as well plug the dunus directly into my smartphone (primary DAP) and bypass the external dac/amp.  please let me know if i'm wrong, but assuming that the impedance plug is an impedance increasing adapter rather than a "(faux) impedance decreasing adapter", that is the expected result.

 

[twister6]

   
appreciate it twister, but based on what i have read here and other places (including: http://www.innerfidelity.com/content/meridian-explorer-case-study-effects-output-impedance), the effect of such an adapter would be expected to be a reduction in sound quality.  unless i'm missing something, that adapter will raise the apparent impedance of the output as seen by the headphones which will result in at least some amount of coloration and muddying of the sound as well as a decrease in the damping effect.  if that's the case, i may as well plug the dunus directly into my smartphone (primary DAP) and bypass the external dac/amp.  please let me know if i'm wrong, but assuming that the impedance plug is an impedance increasing adapter rather than a "(faux) impedance decreasing adapter", that is the expected result.

 
True, it's not a transparent solution.  But I haven't heard any coloration changes, at least with a pair of IEMs I tested (ZA Doppio).  Of course, it all depends on the headphone.  At the same time, when I tried my "reference" pair of ZA Tenores that work fine as is due to their lower sensitivity, and compared with and without 100ohm adapter, I noticed a reduction in airy details.  Sorry, I'm not aware of any other solution, perhaps someone else can chime in?

 

[mindbomb]

nvm

 

[Zenbun]

Anyone know if there are any impedance plugs that have just 10-20 ohm?

 

[ozkan]

  Anyone know if there are any impedance plugs that have just 10-20 ohm?

 
You can choose between 15 and 620 ohms from this seller. 
 
http://www.ebay.com/itm/ETYMOTIC-ER4P-TO-ER4S-RESISTOR-ADAPTOR-3-5MM-PLUG/291329605627?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D30542%26meid%3Ded9fbaa7793c46b894b171f2cf8893e5%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D281657676624&rt=nc

 

[USHI]

Does anyone know where I can get the UERM impedance adapter ( not the airline attenuator ) or have one and dont use it?

 

[Luckbad]

Is there any consensus about which of these are particularly good? I'd like to get one so my IEMs pair better with a couple of my amps. Thanks!

 

[DrKC]

I may be missing something here as I have not read the whole thread.  What I can gather is that those with hyper-sensitive iems are looking for a form of attenuation to lower the noise/hiss from an amp.  This seems to have become balled up with output impedance effects on frequency/amplitudes.
Let's just start with an ideal amp that has zero ohms output impedance.  We'll plug our headphones in.  Headphones have an impedance not just a resistance.  This impedance will vary with frequency.  As long as our amp stays at zero ohms output Z, any variations of amplitude due to impedance changes will be strictly related to the headphones - not the amp.
If we add pure resistance - no capacitance or inductance - in series with our headphones, the amp will not change it's behavior or alter the sound quality.  This resistance (formulas for impedance or Z are easily found on the net) will present a higher Z load to the amp and reduce the output current.  The overall variation in impedance will be somewhat swamped by the pure resistance.  If the resistance is high enough, the varying impedance of the phones will appear to diminish over frequency.
To make a long story short, adding only resistance in series with your headphones will result in some attenuation and a change in the phones apparent impedance.  It doesn't affect the sound quality of the amp.  If the amp has a significant output impedance, this is another kettle of fish and reflects the issue discussed at Innerfidelity. 
The cables mentioned most likely have only resistors in them.  They are most likely in series with the signal lines or there is a single resistor in the ground line.  These will not lower the sound quality like an amp with high output impedance. 

 

[paaj]

I must say I liked the previous theory better
How else to use a headphone like the Q701, which is supposedly designed for 120 Ohms output, properly?

 

[Luckbad]

I received the 75 Ohm impedance resistor adapter from AW Audio Accessory (awwan) today. It's very high quality and lets me notch up the volume several degrees, gettnig my 16 Ohm IEMs out of the imbalanced volume land they resided in with my Vorzuge VorzAMP Duo (at least for all day listening, they were just a little too loud. Now they're not). I'm hearing no reduction in sound quality, but this weekend I'll test frequency response and all the rest with it.

 

[landroni]

  I received the 75 Ohm impedance resistor adapter from AW Audio Accessory (awwan) today. It's very high quality and lets me notch up the volume several degrees, gettnig my 16 Ohm IEMs out of the imbalanced volume land they resided in with my Vorzuge VorzAMP Duo (at least for all day listening, they were just a little too loud. Now they're not). I'm hearing no reduction in sound quality, but this weekend I'll test frequency response and all the rest with it.

Did you complete the tests? Still happy with the sound quality?

 

[Luckbad]

 
Did you complete the tests? Still happy with the sound quality?

 
I totally haven't yet. I keep forgetting the adapter at work every weekend. I've been using it for a couple weeks and I'm happy with it.
 
I'm also going to eventually build one of these after I learn to solder and such: https://diyaudioheaven.wordpress.com/headphones/headphone-attenuation-adapter/
 
I'll try to remember to bring the thing back with me soon.