Are there *easy* mods to a '7? Ampeg V4 to increase clean headroom before distortion? I get a useable range up to around 10o'clock before the distortion starts to become too noticable. Yeah yeah I know this is normal... It's still running it's original Magnavox 7027s, most preamp tubes are still Magnavox, with a couple of others (RCA, etc). Would changing to 6L6GBs (or another tube) give any benefit? How about swapping to lower-gain preamp (12AU7, 12AT7) tubes?