SF Assemblage ST-40 tube amp?

You will probably write me off as "the lunatic fringe", but I have a few words of advice for you if this is your first tube amp. To get the real MAGIC that the vacuum tube has to offer, you need to look for the following types of circuit: Point to point wired-no printed circuit boards; only two output tubes per channel, regardless of the power output (this is assuming that you are interested in push-pull amps as opposed to single ended); simple circuit, using minimal number of parts; and, tube rectification. True, you can get good sound from some designs that do not incorporate these features, but, most all vintage products are built this way and can be obtained for minimum dollars. Do not listen to people that claim all old tube amps sound "warm, veiled, or murky" Some of these designs have a clarity and transparency (true transparancy) that will blow away many modern multi killobuck products. Do not be afraid to slightly modify the input circuit. Remember that everything that happens before the input tube is sacred. this means that you should add good input jacks and eliminate any pots. or input caps if possible. I find that true tube magic comes from lower powered amps, assuming that you have a compatible speaker.

Carl, you are right about the severe impedence dip being inappropriate for a low powered tube amp. Speaking of Maggies, here is an interesting story about my first tube amp: For years I enjoyed the sound of my MGIIIA's with a pair of Adcom 565 300 watt per channel mono amps. One day I answered a newspaper ad for a reel to reel tape recorder. The tape deck was junk, but the guy had something else that caught my eye. This was a set of Fisher components that he had cannibalized from a huge console stereo. I bought the tuner, preamp, and two mono amps for $100.00! So, I get home and try the amps out first on some old Boston A60 spkrs. that I use in my Video/TV system. The sound was quite good, and it surprised me how loud these little amps would play. They use a pair of 6BQ5 output tubes and probably put out only 15-20 watts. I couldn't resist the temptation to try them on the Maggies, thinking that I could always turn them off quickly if there were any signs of strain, or FIRE! But, you know what? These little amps were just blowing away the big solid state Adcoms! The timbre, the clarity, the sense that the musicians were in the room, even the bass was more natural. All of a sudden the music just made sense. I walked around for weeks with a secret inner smile like I had had some born again religeous experience. I don't know how or why these amps work so well, but I can tell you that I have since spent thousands to try and find something better only to come back to the Fishers again and again.