Oh very nice find!
Iām searching for a Alpha Omicron clone 
That would be super awesome, itās basically tied for my favorite Darkglass pedal with the Microtubes X.
I want to put a nice word out for Musikdings, they have really really excellent customer service. Great selection of kits too.
A brief guide into tracing out a PCB to convert to schematic ; B3K Clone :
Now that is dedication and patience. I was wondering how people did this because I couldnāt think of a better way than brute force. And it turns out they useā¦ brute force 
I already did that for full amplifiers 
and I plan to do it very soon with the DG Vintage kit, because I canāt find the schematics
ooh thatās like gold
ānew old stockā stuff 
I donāt know yet if I will invest time to trace the PCB of the Darkglass Vintage Microtubes. might be interesting ā¦ but long ā¦ but interesting ā¦ but long ā¦ 
I contacted the Shalltechnik guy to ask him for the schematics. he explained me that his hands are tied regarding to the particular case of the GUMA pedals ā¦ what I understand is that there are legal considerations. so, even if I trace the schematics I wonāt be able to share it publicly here.
I swear I have seen them somewhere.
the B3K schematic is available but I was unable to find it for the Vintage Microtubes. I guess those are pretty close, thatās exactly what I want to determine ā¦ well at this point Iām almost sure I will trace the PCB.
I finally found some time to finish this preamp yesterday evening. So, itās the Shalltechnik Growling Krizzly Deluxe, which is the full reproduction of a Gallien Krueger 400RB preamp (with footswitchable boost and effect loop, and all the voicing switches).
It works perfectly and sounds great.
So cool. Post audio samples!
yeah I have to find a bit more time for this 
but yeah it sounds pretty much like a 400RB
Dude thatās awesome! You even made it look really cool. Iām more than a little jealous right now.
Did you make any modifications to the original design?
I modified the label sheet but from an electronic perspective itās 100% the original design. Thatās what I wanted : a pure GK 400RB preamp.
That said, if I had to re-build one, Iād change one small thing : the location of the āBoostā LED and the way that the LEDs are wired. the anode circuitry is not very logical for the Deluxe version (but it is for the Basic one, with only one footswitch). nothing very important.