Justin:

Beware of advice from this particular source, some salt is required.
The amps from the perpetrator of this site don't work. Do a search on
this NG for the history.

That being written, some advice from a Fix-It type:

a) Chinese amps tend to be of minimal quality, and so become attractive
primarily to the price-driven. I am presently rebuilding a pair of
guitar amps for a friend that were awfully cheap (single-ended
6BQ5-based units), but each needs a substantial circuit rebuild to
remove the hum at low volume and the whistle at higher volume. Go
figure. It's only a couple of bucks worth of parts and a couple of
hours time, but there should be no need for it were the amps designed
properly from the factory.
b) I boggle at the concept of purchasing an amp under 'sales-final'
conditions unheard. Sure, at a flea-market at a cost similar to a
Mocha-Latte-Grande at Starbucks, but not for real money.
c) Building it yourself is a worthwhile endeavor. But given the very
real problems with SET amps, coupled with the very real problems with
tube amps in general, I would strongly suggest that if you choose this
option, you start with an established and proven source and an
established and proven circuit requiring a minimum of test instruments.

d) And what is your goal? Do you have speakers that are compatible with
a flea-powered amp? Do you enjoy music that is sufficiently 'simple' to
be compatible with both? Is it the concept of SET that is appealing?

Yeah, yeah... we purchase on emotion and justify afterwards. But the
potentialf for Buyer's Regret should at least be minimized.

Peter Wieck
Wyncote, PA