
Hermansson Amplification
Active member
I've modded another Marshall JCM 900 SL-X.
Here it is before the mod.
You can see some electrolytic caps were swollen, these are now replaced with new caps with higher voltage and temperature rating.
And here it is after the mod. The whole preamp circuit is revoiced and changed to get a tight and focused distortion with a lot of sustain. The power amp is also revoiced and got a punch control.
The customer who ordered this mod plays in a Iron Maiden tribute band and wanted the amp to handle classic Iron Maiden sounds.
Here’s a sound clip of it:
Guitar straight into the amp.
TC G-major in the loop for some delays.
Cab: Malmberg 4×12 with old Greenbacks.
Mics: Golden Age R1 mkIII and Tascam DR-40


Here it is before the mod.

You can see some electrolytic caps were swollen, these are now replaced with new caps with higher voltage and temperature rating.

And here it is after the mod. The whole preamp circuit is revoiced and changed to get a tight and focused distortion with a lot of sustain. The power amp is also revoiced and got a punch control.
The customer who ordered this mod plays in a Iron Maiden tribute band and wanted the amp to handle classic Iron Maiden sounds.
Here’s a sound clip of it:
Guitar straight into the amp.
TC G-major in the loop for some delays.
Cab: Malmberg 4×12 with old Greenbacks.
Mics: Golden Age R1 mkIII and Tascam DR-40