No loop, guy I got it from said it was ordered with one but not installed. Might do that down the road but not sure if I've got room for something pedal friendly like the iron sounds kit in the smaller 50 watt chassis. Also, I forgot to thank Nik for answering my questions, he identified the amp and original mod which was the one wire mod on a switch and gave me some pointers on tweaking it before I did this latest project.

It's 3 stages cascaded plus a cathode follower, the "plexi" mode switches out the second gain stage and isn't a Plexi circuit wise but the gain level and tone are pretty close. Master volume is active in both modes so you can get those Plexi tones at lower volumes, although it sounds better cranked up of course. Neither mode is the same as the original anymore, whole different animal now. 

I've added a couple things since, a switch to raise the second stage's cathode bypass cap value for more thump and a switch to drop the second stage grid resistor's value for a touch more gain and a mid boost. Waiting on some diodes in the mail to add a Jose-style clipping circuit switchable on a push-pull pot too.

Love playing with this thing, it sounds killer and the turret board lets you try out a bunch of different stuff.

I picked up a Ceriatone 1987 plexi copy about a month ago. It was pretty good stock but I wanted to mess with it a bit. I emailed Dave Woodhouse at Baron Amps asking what he would recommend for an FX loop, he answered and then followed up with another email asking how far I wanted to take it mod-wise and that he had some ideas. Answer was, pretty far.    Dave was kind enough to draw up a layout to mod the amp and walk me through the whole thing, can't thank him enough for his help on this project.  I'm still a novice for sure but I learned a ton from him and the resources he pointed me to, this was definitely a great learning project for me.





The amp now has two switchable gain modes, 2 stage Plexi-ish and a 3 stage high gain, master volume, presence, thrust and chunk controls and a 3-way bright switch on the gain pot. Sounds freaking amazing now IMHO. The clips are straight off my DR07. They don't really capture the tone as well as a proper recording setup would but I don't have one so this is what you get- 

High gain mode with the gain up a bit
High gain mode with the gain down
Plexi mode

The amp cleans up really well now with the guitar volume, all those are straight into the amp with no pedals in front and just rolling back the guitar's volume pot for cleans. Really happy with the way it came out, thanks again to Dave for the layout, advice and answering all my dumbass newb questions  , Randy at Vintage Amp Repair and Eric Hellstyle on here for their input and Paul Kress for a killer job on the headshell. Much appreciated guys! 

Got it figured out thanks to Nik, much appreciated man!

Got my hands on a Plexi 50 that appears to have some factory mods. Anybody familar with this kind of stuff? Looking for info on what was done, it's way different than the layouts in the preamp. Serial number is 190209-10 and the output transformer says January 2009. Thanks in advance for any help guys!

Just wondering what tube types can be run in these, I just picked up a Plexi Lead 50 watter, output tranny says it's a 2009. With proper biasing what all can be run in there?

A layout for this on a switch would be cool if you get a chance.