Suggested as a favourite along with the Wampler Plexi-Drive by Ding on another post, so thought I would take a look at the Ramble FX Marvel Drive 2.2
They're clearly going for a Marshall vibe, and they have some success capturing this through the sound of the video demos.
Thought I might add the Wampler Plexi-Drive to the list after I did another Benson layout, as they are similar in many ways. Just look at the two schematics side by side, and you'll see what I mean.
Like anything involving JFETS, choose the resistors going to the drains to suit your JEFTS; they can and often do vary. Usually, aiming for half voltage on the drain is an excellent place to start; this is where a breadboard and some clips come in handy.
