| Note: the modifications listed here are a guide to services we offer and should not be undertaken by novices.Valve amplifiers contain high voltages which can cause death . |
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| MARSHALL JCM800 | LUCAS MILES AUDIO AUSTRALIA |
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The Marshall JCM800 series of amps are notoriously bright and treblely.The unit modded here is a 50w Lead Series ,split channel version , 2205/4210 .The aim of the mods was to rid the amp of its thin sound and give it body and tone like the JMP's / Plexi Marshall's but still have the drive and gain of the JCM's. Here we go... |
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Intially we remove the brightness cap C3 470pf then we change C7 from .0022uf to .02uf. This will the remove quite alot of bightness from the sound.
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Next we change the plate resistors R7 470k ( V1b) and R14 150k (V2) to 100k which changes the buzzy tone to a more Marshall sound. |
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Next we change the cathode resistor R16 1.5k on V2 to 820 ohms.This makes the amp more responsive and adds a bit more gain. |
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Finally we change all the signal and coupling caps , the generic red Wima's get changed to Sozo Vintage Mustard capacitors. There are 11 in total .The Sozo's are premium hand made capacitors based on the original mustard caps found in early Marshalls and other vintage gear. These caps add body and fatter tone and the end result is now we have a JCM that has that vintage tonal character with heaps of gain and drive. |
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