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Hi, I know there has been loads of threads about modding JCM 900's but I just wanted to ask a quick few questions. I wanted to find out about modding my mid 90's dual reverb to a more traditional Marshall sound and came across this mod on you tube:
Marshall JCM900 dual reverb, all tube preamp mod:
Here's what I changed in the amp:
1] C27, (4n7)snipe one leg off
2] C35, (220pF) to 100pF
3] R42, (10k) piggy back another 10K over it.
4] D10, (diode) snipe one leg off
R60, (470k) Pickybag 47K over it
R13, (220k) snipe one leg off
https://www.youtube.com/watch?v=dOyCfyDcVHQ
The results of the mod on the video sounded good. I just wondered, electronically speaking, what the mods actually do to the amps circuit and if there are any dangers in doing this to the circuit. I'm not a complete novice, I have built a few 5E3 and JTM-45 circuits in my time. Any help would be greatly appreciated.
Marshall JCM900 dual reverb, all tube preamp mod:
Here's what I changed in the amp:
1] C27, (4n7)snipe one leg off
2] C35, (220pF) to 100pF
3] R42, (10k) piggy back another 10K over it.
4] D10, (diode) snipe one leg off
R60, (470k) Pickybag 47K over it
R13, (220k) snipe one leg off
https://www.youtube.com/watch?v=dOyCfyDcVHQ
The results of the mod on the video sounded good. I just wondered, electronically speaking, what the mods actually do to the amps circuit and if there are any dangers in doing this to the circuit. I'm not a complete novice, I have built a few 5E3 and JTM-45 circuits in my time. Any help would be greatly appreciated.
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