Here is a link to another thread here on the 'gon:
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1220502548&openflup&27&4#27He is using ZUs.
Setup is everything when you have speakers like this. If you also combine that with an OTL, you will have a very revealing system. The problem is that it might reveal more than you want to hear!
One of the bigger problems we run into is someone gets our amp(s) and then does not realize that their digital gear is really not all that great. The S-30, like all OTLs, has lots of bandwidth. It reveals poor digital gear for what it is.
Now some people might think that this is the fault of the amp but its not- revealing is revealing. Most SETs lack real extension on top (unless they are very low power), and due to their even ordered harmonic distortion, they sound quite rich (the ear perceives harmonic distortion as tonality...). SETs often add some of the missing harmonic richness that bad digital is lacking, plus smooths over the raucous high end. But it would be a mistake to think that that is musically right.
Now if your digital is working properly or if you play analog the S-30 will come off as quite relaxed, plus you get more detail (and in case anyone has got the wrong impression, this is true if you have a good SET too). 'Relaxed and more detailed' is the result of less distortion; ultimately you get more music.