in a thread i posted in GG&A Goldenglove reccomended that i ask this question here. i know the jcm 900 dual reverb uses diode clipping but does it use it for both channels or just channel B?

i have looked at schematics but have no idea how to interpret it. is there anyone that knows how to read it? heres a pic

the reason i ask is because i am thinking of putting a clean booster in front of the amp to boost the gain without changing the tone (like an overdrive would). i have been told though that it would sound bad since the clean booster would be overdriving the diodes rather than the tubes. i thought it might work if the diodes arent on channel A. any thoughts or suggestions?