That's called a hybrid amp.

A few blackstars do that, vaccuum preamp and a solid state output stage. Oddly enough, most of those use a linear psu. The design I made uses switched psus with a vacuum preamp and vaccuum output. It has thunderous output power in 1/3 of the size/weight of a comparable power linear amp

So you're using a nonisolated power stage to avoid the transformer and diodes? The transformer also provides isolation from line voltages. Are you sure there isn't a reason the trade-off went the other way?

Linear power supplies voltage sag as they're overloaded. This famously exploited by some players to create "brown tone", or audio compression, as the input signal gets louder. I don't particularly care for this type of compression and a lot of other players don't either.

As far as safety, the input transformer is -boosting- your 120vac to 400vac-500vac :) So it's not protecting you from anything :D

My topology could be arguably safer... First, 120vac->24vdc via switching PSU. This actually provides the isolation you refer to. Then the 24vdc is split, part of it is switched down to 6.3vdc for the tube heaters and the other part is put through a ZVS boost circuit 24vdc->376vdc. Even with the double conversion, my efficiency is about 78%! I have complete isolation from AC via the first power supply. I bond my negatives to earth for safety. The best part is, this amplifier is dead quiet because the switching noise is very easy to filter.

There's absolutely nothing in this topology that's new; you're using bog standard off the shelf components that can be bought anywhere...?

I don't suffer from "not invented here syndrom", of course I did! Not going to take up glass blowing and make my own tubes lol.

There's also this mentality among Marshall/Fender that the 1960s-1970s were the only way to design guitar amps. Very few amp makers have diverged very far from their designs.

Among players, there's a lot of cork sniffing and brand worship unfortunately. I feel like "weight" is something tangible that anyone could measure: Saving 5-6lbs, running cooler, and being more portable are things that would appeal to a lot of people.

My point is: this shit exists already. There's nothing new about it.

It's hilarious; if you're out creating and inventing doesn't matter what subject area, you will always run into somebody who is dissatisfied with their own life and is out to crap on your creativity. You sir are correct, it does exist, because I've created the only one ;)

From my perspective it looks like somebody actually in industry telling a delusional 'creative' type that they should have done better product research before declaring they had something new.

Here's a hint: Let's say we're both right, hypothetically - no other product does this! However, since there's nothing about the design that's intrinsically yours (IE - it's combining a few undergraduate EE course projects at once) somebody else will go make it in China as soon as you demonstrate that there's a market.

Unless, of course, you really have discovered some new area of AUDIO CIRCUIT DESIGN (just about the simplest shit there is, circuit-design wise). Not...very...likely...

Well then, it's a good thing your perspective doesn't matter to me, you've proven you don't have the faintest clue what you're talking about ;)