There are lots of inexpensive tube amps that have been around quite a bit, with many happy users, that are clearly proven designs - DarkVoice 336i, Little Dot II/III, WooAudio WA3, Ming-Da MC84-07C, Musical Paradise MP-301, AudioTailor Jade...just off the top of my head. All under $500 - the MP301 is $199 new! And the DV336SE is just 249. I think the LD II is something like $199 as well IIRC. The DV336SE uses the 6AS7G like the amp you got. And the WooAudio WA3 uses the 6AS7G and the 6DJ8!
Don't let this scare you off of tube amps. You just got a bum steer.