@iFi audio
Since I'm a happy micro iDSD owner since 2014 I already knew the impressive iEMatch feature very well - it just works flawless - no question. My big question was more: how this tech works without any active components - so with your iEMatch adapter.
I ordered few days ago the iEMatch adapter for my other DAC/AMP devices which provide too much hiss to my sensitive IEMs/CIEMs. So far so good, it worked as it should now with the iEMatch adapter - every hissing device is now
dead silent no hiss anymore - absolute
zero.
Sure this "trick" could be done with any cheap impedance adaptor with a resistor built-in, but the side effect of this "solution" is that the output impedance of the source device are increased and the frequency response of the IEMs/CIEMs are modified (mostly really bad!).
So now I have read the details that with this passive unit of iEMatch and the setting "Ultra" it keeps just ~ 1 ohms output impedance, which is insane with a passive and not active component, my questions are how is that possible - to eliminate the hiss without using resistors? How you avoid this side affects of "regular" impedance adaptors?
Since I'm a technical engineer I did a few measurements by myself and I'm bit confused. First I measured the source device without iEMatch and with my multimeter and I got 0,6 ohms so far so good. I attach now my sensitive 12 driver CIEM no frequency response altered since we keep the output impedance at around 1 ohms:
2nd run was the same setup but iEMatch in between and setting to "High" and I measured again with my multimeter and I got 2,6 ohms (official > 2,5 ohms) very good results and since it's over 1 ohms the frequency response is altered - that is also just normal and I knew this - no need to talk about that's fine:
3rd run was the same setup but iEMatch in between and setting to "Ultra" and I measured again with my multimeter and I got 1 ohms (official 1 ohms) very good results and now my question is why (even it's below 0,5 dB frequency response changes) does look like this frequency response so "fancy" right now? I can't hear this, maybe related to the tech to eliminate the hiss without increasing the output impedance? My ADC is a bit old, but still very good - it's a Creative E-MU 0404 - I would never say never (like a measurement glitch) - but I do this since years and I also did a few runs to verify and I'm very sure measurements fine I compared with other gear too.
A summary from all runs in one view:
Finally I'm very happy with the iEMatch, it would only at least for me (and I guess others too) really intesting if you may shed a bit light on the tech inside of iEMatch or may explain a bit how this passive unit works so well. It's really a beast hiss killer without audible side effects with very sensitive IEMs/CIEMs.