[James Romeyn]

Today someone told me a particular tube amp maker employed SMPS in at least one of his designs.

I have long thought it good to employ a superb SS preamp (or better yet, transformer based) with a glass amp driving the speakers.  RM-200 architecture seems to mimic my philosophy, with a SS input and tube output section (uncommon among tube designs).  Roger seems very comfortable in thinking outside the box.       

What are pros/cons of SMPS for tube power amps in general, or Roger's amps in particular?   

[G Georgopoulos]

What are pros/cons of SMPS for tube power amps in general, or Roger's amps in particular?

One pro is the ps is regulated...however tube ps are mostly unregulated...both of them work fine i think...

[Roger A. Modjeski]

Today someone told me a particular tube amp maker employed SMPS in at least one of his designs.

I have long thought it good to employ a superb SS preamp (or better yet, transformer based) with a glass amp driving the speakers.  RM-200 architecture seems to mimic my philosophy, with a SS input and tube output section (uncommon among tube designs).  Roger seems very comfortable in thinking outside the box.       

What are pros/cons of SMPS for tube power amps in general, or Roger's amps in particular?

The reason the RM-200 has a SS input stage is that I wanted superb common mode rejection, no noise and no fussing with input tubes. The RM-200 is a very pure SS cascode stage. It does the work of 2 tubes. I still prefer at tube preamp.

Lets define our abbreviations before we use them please. I presume SMPS is switch mode power supply. Yes I have considered them. To my knowledge no one makes a high voltage high current one that would work for a power amp. My biggest reason for not developing one is reliability and who is going to fix it down the road. Most SMPS are not repaired, they are too hard to repair. So where do you get another one years from now? A traditional transformer, diodes and capacitors can be fixed by a monkey. If I do develop one it will be very simple with replaceable parts clearly marked.