I'll post on YouTube when it's ready.
I call this design "dial-an-amp". You can literally dial up any amp you want.
Up front, is a very precise clean section. The first thing is, you can dial up the cathode cap in the very first section. This gives you varying degrees of "bass rolloff", at different frequencies. Then your selected signal is fed through a tone stack, which you can switch between TMB (Fender) and Baxandall-with-midrange. Then you boost the 1 volt signal up to about 20 volts, and feed it through the coupling cap of your choice. In other words, "after" the up-front tone stack you can roll off some more bass if you wish, at different frequencies. So like, you can boost the bass and mids in the tone stack, and then roll them back off at a different frequency, this way you get complete control over your mids. If you want a Mesa-style sound with fat mids and skinny edges, you can get that.
After that you run through a switchable gain stage, which is very much like a Soldano but you can take the cold clipper out of the stack. If you take it out, you run straight from a 20 volt drive into a cathode follower, which is the Marshall sound on steroids. If you leave the cold clipper in, you can switch the cathode resistor to get any amount of clipping you want. At 39k it's a Mesa Dual Rectifier, at 10k it's a JCM-800, at 4.7k you get Scruffy's favorite setting which no one else has, or you can just run it at 1.5k like a normal gain stage which puts you in Bogner/Engl/Krank land.
While you're doing all this, the gains are automatically adjusted so the signal that appears at the reverb input is consistent. You can the tap the reverb into any stage, and mix it with the drive from any stage. The phases switch along with your settings, so your reverb is always in phase with the drive.
If all this sounds complicated, it's not. You have two knobs, "amount of drive" and "amount of reverb", and then you have a master volume. There is a second tone stack between the reverb and the master volume, so you can dial up an "overall" contour for whatever comes out of the mixer. This second tone stack is more like a Marshall, it has the presence control and some NFB contouring.
If you want to run completely clean, you can switch out the entire gain section, then you just get a Twin Reverb. If you want to sound like a Marshall instead, you can choose what "type" of Marshall, JMP, JTM, or JCM. If you switch the preamp tone stack to Baxandall you're an Ampeg or an Orange. (And in Orange mode you can switch the coupling caps just like the real thing).
To get to never-never land, you switch everything in and dial back the drive to the cathode follower. There's so much gain you can get an extremely ratty sound out of the reverb, without killing the springs. You can get some delicious reverb tails by dialing in the thump in the drive section, then switching the reverb into crunch mode and boosting the dwell. When you rake your guitar strings it goes thump-thump-thump and then shhhh. It's a wonderful effect for pizzicato. For southern rock you can use a cleanish front end and set the reverb so it's just on the edge of crunch, this way you get varying degrees of bite depending on how hard you pick the strings. If you like to shred, or tap-and-shred, you can boost the drive and turn down the dwell, that way your tapping will be delivered with clarity even when the overall sound is rich with reverb.
It's a tremendously versatile and responsive amp. I've done similar designs three times before, so I kinda know what I'm doing by now. Only last time I used a 12AT7 PI, which can't really drive the KT-88's hard enough. It sounded great about halfway up but lost some oomph at full volume. "Too clean", is what it was lol. This time I'm using two 12AU7's instead of one 12AT7, so instead of being forced to crank the signal to drive the power tubes, there's enough clean volume to push the KT-88's up into blues land, get that really sweet slightly crunchy gain the blues players love, only LOUD, much louder than a tweed Twin. With this amp you don't have to work to keep up with a loud drummer. You can still feed into the board if you want, there's an effects loop and a separate tap for "reverb only", so if you want you can disconnect the power amp and run the entire front end at 3 watts. The recording engineers love this, they can do whatever they want with the sound and you'll have just enough monitor to hear yourself. They won't have to put you in a sound booth when you want Zakk Wylde, you can just sit there on the couch next to the engineer and do the whole thing at Pignose volume. Then step outside, engage the power amp again, and amaze your fans with what you just learned in the studio.
........somewhat a dying art.......
~S~
