I have a 50 watt Duophonic with AFD dirty channel and a Corona (Fender Blackface) Clean channel. It's the amp on my avatar. I had Randy do a faceplate with my first name on it, told him "At my age this is the closest I'll probably ever get to an endorsement deal." :laugh:
I have had this amp for close to 6 months now and it's still impressing me!
The AFD channel (Appetite For Distruction) is a modded version of a Friedman Brown Eye (I think) and not the SIR 36 Caswell mod. There is a gain knob then a toggle switch for a gain boost. Since building mine he has started putting the gain boost on a knob instead of a toggle switch, which I wish mine had lol. The amp has a Deep or Resonance knob like a 5150 so it's got the Marshall grind but plenty of low end to spare as well.
If you're accustomed to the very quick way a vintage Marshall reacts to your playing well that parts not there, it reacts like a Fender in that regard. Doesn't change how good it sounds though. The Corona is clean headroom for days.
The effects loop is also excellent. I'm running a TC Electronics Nova System through it and there's not really any tone suck to speak of. It does change the base sound a little, but that is unaviodable.
Some might not know this name, but Randy has built an amp for Frank Marino!