revision preference src: Although associated with Marshall amplifiers (100 watt non-Master Volume Superlead heads and 25 W Celestion Greenback speakers), Robertson has been known to use Mesa Boogie (100 W Dual Rectifier head) and Soundman amplifiers. <SEP> tgt: Associated with Marshall amplifiers (100 watt non-Master Volume Superlead heads and 25 W Celestion Greenback speakers). Robertson has been known to use Mesa Boogie (100 W Dual Rectifier head) and Soundman amplifiers.