SLAM means stereo limiter and microphone preamplifier
FET Limiters, Stereo Link, and VU Metering
No mic preamps or instrument inputs. Instead the tube sections are paralleled for lower noise and distortion
All pots are replaced with rotary switches for detented resettability and easier calibration
The mastering version has a true hard-wire bypass function, which is not possible on the regular version with mic preamps, etc. What was the Left Bypass, becomes the full Bypass (in stereo and hardwired). No separate L & R bypass buttons