I thought the ESP 950 sounded amazing out of the SRM-717 which you can pick up for around $1k. The best stock amp I've heard from Stax --- if you can find one. I eventually gave up on the ESP 950s tho after sending the drivers back to Koss literally six times only to have them continue to squeal and crackle. I even got a second set on the secondhand market only to have the same problem. My house isn't that humid. It's a shame because these are phenomenal when driven well. Certainly better than the 'Baby Orpheus' (HE60) IMO.

In college I had a Stax Lambda Nova system that I got for well under $1k (both the amp and headphones --- used of course --- before the secondhand planar market became ridiculous). Even though I had it plugged into an old Aiwa CD player, I still count this as among my all time favorite systems I've owned. The sound lacked heft but it had this really unique quality of seeming to materialize out of thin air, something that made for an addictive listen.

I think used Stax gear is a great way to go for some people, provided they can find it at a reasonable price nowadays. Those old plastic Lambdas and Sigmas are quite durable aside from the gross foam.

SRM-323 is better than E90 w/ ESP950. I used to own the SRM-323. That being said, avoid SRM-323 if possible and spring for the 007, 727, 717, or a vintage SRM-T1. The SRM-323 never sounded quite right to me. Hard to explain, but it has a strange hollowish twangy coloration. The tubed 007 sounded better than I expected, and the SRM-727 is quite good despite STAX mafia's not unfounded concerns with it.

marvey,

Out of the 007, 717, 727, and SRM-T1 -- do they sound similar, or is there a pecking order in terms of performance?

Regarding Stax amps, I wouldn't flat out recommend one amp over the other...it depends on which headphone you plan to drive with it.  For the Lambda series I generally prefer the tubed Stax amps because they help tame the brightness; for something like the 007, I prefer the 727/717/323 because of the increased power and driver control.

Don't be afraid to look on HF for pretty much any question you have regarding Stax.  The Stax threads over there have tons of info and the participants are generally experienced in the hobby.