They can be wired to run in triode mode, and will do 30W. In pentode mode, they are rated 60W @ <1% THD / 50W @ <.5% THD. You may be thinking of the MK II(actually rated as a 50W amp, but did 35W @ .5% THD.
I'd have to agree that $3K is high, for a pair of Dyna Mk III's. A really nice(operational and stock) pair, might bring around a grand on eBay. Matter of fact: (http://www.ebay.com/itm/Dynaco-MKIII-tube-amplifiers-pair-sequential-serial-numbers-s-n-tags-on-100-v-g-/110835587093?pt=Vintage_Electronics_R2&hash=item19ce50d815)
Before Dyna, before Dynakit, the company manufactured transformers. They realized that between the Output and Power transformers they had most of the parts value of an amp. So, they put out the amp kits.
I think the 60 watt monoblock was over $120 when the rule of thumb was a dollar a watt.
Classic equipment such as these Dyna's command very high prices in Asia due primarily to their classic status and collectabilty. The Mk III's can sound pretty good particularly after updating. But, $3000?! I don't think so. Way too much, in my opinion.
Their transformers(the foundation of a tube amp) are very good. The sound can vary from tubey/euphonic, to very clean and extended, depending on the owner's choice of tubes, caps, resistors and wiring. Left stock; you'll have the first presentation.
You must have a verified phone number and physical address in order to post in the Audiogon Forums. Please return to Audiogon.com and complete this step. If you have any questions please contact Support.