Congrats on a fine acoustic amp.
I wonder if an acoustic amp with tubes even exists? Unlike electric guitar where you have the interaction of the guitar to the tube amp, maybe that might not work with acoustic. The original poster of this thread would like to see PRS build an acoustic amp, but he says, " I would like to see it be 2 channel, 100 watts solid state of course," which is why I question this. We want our electric guitars to get that natural tube breakup. I don't think this is the case with acoustic, we want that clean, pristine acoustic tone, emulating how the guitar sounds unplugged, just at stage volume.
Anybody have any thoughts or comments on this?
Lots of people use tube gear for hi-fi, which is essentially what an acoustic amplifier should be - high fidelity to the source, as opposed to the amp contributing large amounts to the sound.
So in theory, you could use a high quality sound reinforcement speaker with something like the tube-powered McIntosh 275s (as the Grateful Dead did), and put out a high quality acoustic tone that would have plenty of oomph and might subjectively be a little "warmer" than a modern solid state amp.
I saw the Dead in the very early 70s at a medium sized venue (Detroit's Masonic Temple) when they were using McIntosh tube gear to power some of their sound reinforcement cabs in their live show, and they sounded very good indeed! In fact, it was the first rock show I sever saw that sounded really high fidelity. It was a beautiful thing.
McIntosh has reissued the 275 amplifier for around $5000. You can find old ones for nearly the same amount, if they're in good condition. An old Dynaco amplifier would also sound pretty good for this purpose, but it isn't as powerful.
Remember that an electric guitar amp is designed to break up, distort, and saturate quickly, while a hi fi tube amp is designed to play cleanly up to its rated power. Also, a guitar amp is designed to have a lot of distortion in higher frequencies, it doesn't have a full frequency response since a guitar speaker cuts off at around 5kHz instead of the 16-18kHz most hi fi speakers roll of at, etc.
So you can't successfully just hook a guitar amp up to a speaker and hope it will do the job. It won't.
Though...some bass tube amps, like the Mesa Bass 400+ actually have a much more linear frequency response than guitar amps; in fact, the Mesa Baron hi fi amp was really based on the 400+ I'm told. And some bass cabs have tweeters for extended frequency response, and speakers that distort less than guitar speakers. So there's that.
I've had sonic success using an Avalon U5 direct box (Class A Solid State), and a Demeter Tube Direct box (each runs around $500) with an acoustic guitar pickup. Note that by "success" I mean that the sound was as good as I thought it was going to get, given the sonic limitations of acoustic guitar onboard pickups, etc., which have never thrilled me.
Of course, the Avalon has the advantage of a built-in tone control with presets for acoustic guitar piezo and soundhole pickups. I've used these both live into the sound mixer's console, and in recordings as an adjunct to the miked guitar (running the parallel outputs into modulation pedals, etc). Both applications work nicely, and in my estimation, achieve nicer sounding results than any of the acoustic guitar amps out there I've worked with, but it's always good to try new things and experiment, so my ears and mind will remain open!