some sensitive earphones (Campfire Audio Jupiter and Andromeda). I like to listen on tube amplifiers made for full-size headphones. I would get a hiss or an audible tone. I simply plug in this device and that distracting noise is gone. The music is then even clearer – and the earphone/amplifier synergy is now even better. I’m now going to try the iFi Ear Buddy, too, to see if that one works similarly, so I can use it in another room. Worth the price to me – bigger difference to my ears than (say) a cable upgrade.

Makes your iem much less sensitive which in turn helps to eliminate hissing that sensitive iems generally exhibit with smartphones.

This is the item you want to get rid of any audible hiss as well as alter impedance output if necessary.

Fixes the hiss on my m9xx dac/amp and on my phone, however it makes audio from the phone a little too low and should require an external amp.

I was skeptical of this finally solving an issue that I’ve had, which is finding a DAP or DAC/ that wouldn’t hiss using my Ultimate Ears Reference Monitors. Unfortunately, many audiophile DAPs and DAC/amps are designed for full sized headphone power, which doesn’t work well for custom in ear monitors. I have used this little thing on a Herus, my audio interface, and can enjoy a black background with less gain, so I can actually fine tune my volume. Another positive for this device is that it isn’t another impedance adapter, which would affect the frequency response of multi-BA IEMs. iFi did some magic with this, and made the ultra level under 1 ohm impedance!

I would say this is a near required purchase for anyone with sensitive in ear headphones or CIEMs.