Crate V18 to Bogner Ecstacy OD

R2 Replace 2k7 with 820R [V1a Rk]
C6 Replace 2.2uF with 0.68uF [V1a Ck]
C1 Replace 0.047uF with 0.0047uF [V1a coupling cap]
R6 (470k) Remove
C2 (.001uF) Remove and jumper
C3 (470pF) Remove and jumper
R10 (470k) Remove
CW1 Replace 250kA pot with 500kA pot & 
CW1 ... add 0.001uF bright cap
R4 (2M2) Remove
R65 Replace 68k with 470k & 
R65 ... add 470pF cap in parallel
Add 500k resistor from V1b grid (pin 7) to ground
Add 100k resistor from V1b grid (pin 7) to SPST footswitch to ground
... [This is a Gain Boost switch normally closed for low gain position]
R3 Replace 220k with 100k [V1b Rp]
R5 Replace 2k7 with 4k7 & [V1b Rk]
Add 4k7 & 2.2uF cap from V1b cathode (pin 8) to SPST switch to ground
... [This is "Structure" switch]
C7 Replace 0.022uF with 0.0022uF [V1b coupling cap]
Add 500k/500k voltage divider to ground between C7 and R61
R61 Replace 220k with 500k &
R61 ... add 470pF cap in parallel
R12 (1M) Remove
R11 (100k) Add 470pF cap in parallel [V2a Rp]
R17 Replace 220k with 500k & 
R17 ... add 470pF cap in parallel
R15 Replace 100k with 500k
R16 Replace 2k7 with 1k [V2b Rk]
C13 (2.2uF) Remove [V2b Ck]

Note: schematic lists several 500k resistors. 510k would be the closest standard value although 470k could also be used