That's a good one!
Monoprice says their 'tube' amp uses a class A/B amplification with a tube preamp stage. This is a pretty good combination.
I have an Odyssey Khartago solid state amp and the Odyssey Candella tube preamp. Sounds pretty darn good. Of course, for a total of over $2,500 it should sound great and rub my leg.
I spoke with Klaus Bunge (Odyssey guy) and he said you have to have tubes in the signal path to get good sound. I agree. The only problem with the Odyssey set up is, not enough tubes, just 2 x 12au7s.
I have had the pleasure of listening to the monoprice 'tube' amp coupled with a pair of M3s. This rig sounds terrific! I had one of my golden eared audio society friends over to get his take. After all, a system with a $150 amp and a pair of used M3s, shouldn't sound this good. He agreed. Sounds great.
When I told him that the amp cost $150, he was stunned. Based on the sound quality, he guessed it cost $700-1,000.
$150. Go get one!
Listener, you're going to love it!