Thanks to Anakchan, I've been able to try a bunch of the top portable amps and sources together over the last few days, as well as some other gear. Here's the list: ALO Audio RX3, CLAS Ray Samuels SR-71B Fostex HP-P1 Triad Audio L3 Pico Slim iBasso DX100 GO-DAP And computer-connected: Audio-gd NFB-16 (I'm awaiting the battery-powered version) Audioquest Dragonfly. More LODs and cables than you can poke a stick at. Some comments I posted on Facebook just now: It would take me forever to write up all the fine details. I was surprised in Tokyo by the CLAS/RX3 combo, so I was glad to finally get a chance to give it a good run. It IS high-end I reckon. The RX3 is a bit clearer sounding than the SR-71B. It also has a more clear "hi-end" sound like my Phoenix amp compared to the L3, which has a "look at me and all my power!" kind of reproduction. I feel the HP-P1 and CLAS are a touch behind the DX100 as sources, itself a bit behind my main DAC rig. I took the DX100 into a hi-fi dealer and used it as a source and pre-amp with a $10k Linn Klimax Twin and the dealer was shocked at how good it is. The downside is the coax digital out of the DX100 is not good quality, so it doesn't make a good conventional transport, but I have used the optical with a few DACs at meets and shops successfully. The 334s are very good, but it has taken me a few days to get to like them. They grated with me at first, mainly due to a bit of a V-shaped sound sig when used with an amp. I say "a bit" because the treble has a peak, possibly at 8-9 kHz which shows up some sibilance on some tracks. The bass is a bit heavy too. I've never been a fan of dynamic IEMs as they tend to make percussion sound flat and lifeless compared to BA IEMs that I've tried.