SET vs OTL

To add to that I have an Audiovalve RKV OTL amp that sounds really wonderful, but 3 watts per channel was never going to be enough so am looking to upgrade soon to a little bit more power, hence the question.

Thanks guys this is absolutely fascinating!
3 specific follow on questions:

1. Other things being equal, the choice then is deciding what hurts naturalness more... (a) the lushness or "smearing" that occurs as the tube interacts with the transformer in an SET, or (b) the fake neutrality coming from the even ordered harmonic cancellation of push-pull in an OTL. Correct?

2. I am not looking for a lot of power as my listening room is small. As such, the choice could likely be between, say, a CARY 300SE (15W per channel) as the SET contender, and the GRAAF GM20 (20 Watts per channel) as the OTL. Not that much difference in price...Theoretically which amp should sound more natural?

3. "its harder to make a practical low-powered OTL", why is this? I have a low powered OTL which sounds great: http://www.audiovalve.de/rkv/engrkv.html

Thanks again.

Just to add to the above, my speakers have a very flat impedance curve (ASA Monitor Pro). Looking forward to clarifications on my 3 questions. Thanks

Atmasphere,

regarding your point on fakeness and removing harmonic distortion... I understand that in an OTL / push pull amp, some of the harmonics will cancel-out showing lowered (measured) harmonic distortion. But if it is the even order harmonics that are being cancelled then the odd-ordered ones are left to dominate, the sound will be much worse/less natural even when measured harmonic distortion. Is this not an issue with OTLs?

As for SETs, the problem is (correct me pls) that even order dynamics can be accentuated by the tube's interaction with the transformer, making the sound more lush/"pleasing" but less natural/neutral.

Regarding my speakers they are Asa monitor pros (http://www.asa.fr/productsPages/gd_monitor_pro.php),
The monitors have a very flat impedence curve and are 8 ohms/ 89db.
They come with a pair of active subs that sort of make up on frequencies below 40hz (cut off point) for where my small OTL amp was lacking.
My listening room is not big and I usually listen to jazz.

Limited budgets mean that one usually buys used equipment from overseas, so it is often not possible to audition... (very hard to find used GM20 Graafs, but did see a Navison Audio OTL on Agon recently). Hence my question on whether a good SET (eg the Cary 300SE) would sound more natural than an OTL amp of similar price/quality.

Sorry, the sentence in first paragraph above should read:

"But if it is the even order harmonics that are being cancelled then the odd-ordered ones will be left to dominate, and the sound will be much worse/less natural even when measured harmonic distortion is lower"..

I do listen near-field and at moderate volumes and am looking to maximise neutrality.
It seems your advice Atmasphere would be to either get an SET with a single gain stage (who makes these pls??), or an OTL.
Thanks!

... and here is the famous SET that generates 150w per channel and a bandwidth of 20Hz-100,000 kHz. Too bad it costs $350,000...
The Wavac SH-833 :
http://stereophile.com/tubepoweramps/704wavac/