Well, I am now listening to the Yarland with all Russian tubes - my 6N3P's came. They sound SOOOOOO much better than the stock Chinese tubes - smoother, quieter. The basic character of the amp remains, but the Russian 6N3P's and the Electro-Harmonix (also Russian of course) EL84's are a very nice combo. This is a cheap upgrade - the 6N3P's were $14.95 shipped from Russian for 6 tubes, and the EH tubes were $20 for a matched pair.
This makes the Yarland a really VERY good sounding amp. Now it competes with the ASL OTL mk III (although I still prefer the ASL amp). The Yarland is very dynamic sounding, while still having that magical tube midrange.
Fairbanks, I totally understand your hesitation to change tubes, and the Yarland is a nice sounding amp with the stock tubes, although one of my stock 6N3's was noisy. But it just plain sounds better with the Russian tubes, IMO.
Either way, huge thumbs up from me. GREAT value, too! A beautiful to look at, great sounding hume tube amp for $350!