Fet version of the JCM800
Frequency response in comparison with the original tube version
The first stage
The second stage with different gain settings
The third stage
Schematics (pdf)
Ready to transfer PCB (pdf)
Upper side assembly (pdf)
Bottom side assembly (pdf)
Assembled board.
With proper assembly, tuning is reduced to the adjustment of the drain voltage of transistors in accordance with the schematic by trimmer resistors.
Controls and input jacks (pdf)
The process of assembling with micro PA.
Samples kindly recorded Denis Soloviev (Denn).
Line recording, checking boost by Marshall Guv'nor Plus
Settings: Bass=7, Mid=6, Treble=6, Gain=7, Presence=6, Vol=8
Normal Output (external speaker simulator Behringer Ultra-G)
1st fragment - Guitar directly
2nd fragment - Guitar trough Marshall Guv'nor Plus (Gain=1, Vol=9)
3rd fragment - Guitar trough Marshall Guv'nor Plus (Gain=7, Vol=9)
Fragments in consecutive order
Trough Marshall Guv'nor Plus (Gain=1, Vol=9)
Settings: Bass=7, Mid=6, Treble=6, Gain=7, Saturation=1, Presence=6, Vol=8
Normal Output (external speaker simulator Behringer Ultra-G)
1st fragment - bypass on (bypass micro PA)
2nd fragment - bypass off (trough micro PA)
3rd fragment - bypass on (bypass micro PA)
4th fragment - bypass off (trough micro PA)
5th fragment - bypass on (bypass micro PA)
Fragments in consecutive order
Trough Marshall Guv'nor Plus (Gain=1, Vol=9)
Settings: Bass=7, Mid=6, Treble=6, Gain=7, Saturation=sweep, Presence=6, Vol=8
EQ Output (internal speaker simulator V30)
1st fragment - bypass on (bypass micro PA)