Two classic amps, two different voices. The Marshall JCM800 is midrange-forward 80s rock crunch; the Marshall JCM900 is brighter, higher-gain 90s Marshall with diode-clipping preamp saturation. Here is how their settings and the records made on them compare.
| Knob | Marshall JCM800 | Marshall JCM900 |
|---|---|---|
| Gain | 6.5 | 6.5 |
| Bass | 6 | 6 |
| Mid | 6 | 6 |
| Treble | 7 | 6.5 |
| Presence | 6 | 5.5 |
Averaged from 84 (Marshall JCM800) and 16 (Marshall JCM900) famous recordings. Out of 10.
Go Marshall JCM800 if you want midrange-forward 80s rock crunch. Go Marshall JCM900 for brighter, higher-gain 90s Marshall with diode-clipping preamp saturation. But the real point: you do not need either one. GuitarToneAdapt takes any tone recorded on these amps and re-dials it for the amp and guitar you actually own — free.
🎛️ Get either amp’s tones on YOUR rig — free →Neither is "better" — they are voiced differently. Marshall JCM800 is midrange-forward 80s rock crunch; Marshall JCM900 is brighter, higher-gain 90s Marshall with diode-clipping preamp saturation. Pick by the tone you want, then adapt the settings to the amp you actually own.
Averaged across the famous recordings on each (knobs out of 10), the Marshall JCM800 sits at gain 6.5, bass 6, mid 6, treble 7, presence 6; the Marshall JCM900 at gain 6.5, bass 6, mid 6, treble 6.5, presence 5.5. The biggest gap is treble, where the Marshall JCM800 runs noticeably higher.
Notable Marshall JCM800 tones include Master of Puppets, Fade to Black, Mayonaise. Notable Marshall JCM900 tones include Dammit, Never forget, Sweet Dreams (Are Made of This). GuitarToneAdapt can re-dial any of them onto the amp and guitar you already own, free.