I'm currently selecting an amp to go with my Shure SRH-940. The options that I've been considering are:
1) Digizoid ZO2.3: I like the small size of this thing, and the bass boost would be nice to use every once in a while. However, I am mostly happy with the bass amount in the SRH-940, and I've been thinking that a higher end amp that improves more than just the bass range could be worthwhile.
2) FiiO E17 Alpen: A little bigger, but still manageable in my opinion. I'm interested in it's multi-functions, but the USB DAC/etc is not a main selling point for me. I am also unsure as to improvement relative to Digizoid given the price, and the lower portability is a bit of a turn-off.
3) JDS Labs C421: I would have to stretch my budget a little bit for this one, and it is even bigger than the FiiO E17. But if it synergizes well with the SRH-940, and is a marked improvement relative to the E17, I might be willing to deal with the bulk.
I would be planning to use the Digizoid with a Sansa Clip+, or the FiiO/JDS with a Cowon or Sansa player (haven't purchased source yet, using phone for time being).
Another branch I was considering was the HM-601 without a separate amp, but it would have to pair substantially better than the above options for me to consider stretching my budget and my pockets even further.
If anybody can provide any opinions regarding the synergy or lack thereof between the SRH-940 and these setups, that would be great.