Coliseum PA with a single KT66/6L6GC power section

[bluesbreaker]

Hi! I'm interested in building a low output (up to 20W) version of a Coliseum PA head using a single tube power amp section, and since a single kt88 would produce more than 20w (I'm guessing), I'd probably have to use a kt66 or equivalent. How difficult would this be? I've never built an amp before, so I'd need quite a lot of tips and info regarding transformers, the schematic itself and so on... If anyone's interested I'm basically going for a Leslie West cranked mic input tone at more friendly volumes.

[EdBass]

Interesting idea, but rather than try to modify the original circuit you would really have to start from scratch, for all intents and purposes EVERYTHING would need to be different from the original amp.
I don't think it's practical to imagine that someone on an internet forum could realistically walk you through a project of this magnitude, particularly since by your own description you have zero experience in doing this type of work.

IMO your best bet would to find a qualified person to design and build your concept; also don't forget to bring them a big pile of money along with your idea...

[bluesbreaker]

Why would you need to redesign the pre-amp?

[EdBass]

While you could likely retain the basic signal path of the preamp, from jump street the power supply would require a total redesign, and from the driver stage back the topography (not to mention the tonal characteristics) of a single ended amp is an entirely different animal than a push pull.
You are dealing with an integrated amplifier concept here, it's not like a separate power supplied preamp/power amp scenario.

Again, I would suggest commissioning a qualified tech if you really want to make your "idea" a "reality".

Best of luck, and I'm sure a lot of the members of this forum would be interested in your results!