I have some mods I want to try on my JCM 800 50W combo (4104/2204 in 2x12 combo form). So far, it has been switched to EL34s from 6550s by a tech and rebiased, he also added a snubber cap to V1 (I read that stability could be a problem with any mods that add gain). I removed the bright cap, which seemed to be a step in the right direction for the tones I want… I want to get rid of brittle ice-pick tones when the gain is around 4-6, running through low input. I would like some more gain/sustain when running through high input. My ideal spectrum of sounds would be like Allman Brothers to Led Zep on the low input and AC/DC to Guns n Roses on the high input (I hope that analogy makes sense). I am probably asking too much, but I am interested in tinkering a little bit with mods that can be easily reversed. Here are the things I want to try: First Attenuator/Peaker… replace with 68K resistor only (or run 2200pF or 1500pF parallel to stock R/C) Mid Pot replace with 50K linear or 100K audio Different cathode resistor on V1A (6.8K or 4.7K) Different cathode capacitor on V1B (.47uF, .33uF, or .1uF) Add cathode capacitor on V2A (.47uF, .68uF, or 1uF) Change presence capacitor to .68uF Change tone slope resistor and treble capacitor… maybe V1B 100K plate resistor replace with 150K or 220K (maybe add “fizz” capacitor… maybe not do this at all, not sure) How do I shop for individual resistors and capacitors? I assume I need all 1/2w resistors in the locations I am looking at, but do any need to be higher? Does metal film or carbon film matter? I see a couple of ceramic capacitors in the amp, but also a lot of rectangular capacitors, what are they? Do I need to worry about wattage or voltage rating when swapping these capacitors? If you read all that and can offer some advice, THANK YOU, I am trying to learn.