SSD Amps - Solid state amlifiers as in transiter / Mosfet / intergrated circuit ( black chips with legs)
Pre Amps - desgin circuit diagrame
Active Tone Controls - as in changing the tone of the audio in circuit
Mixers - large and small multi channel units for mixing may sound sources together
Power Amps - Solid state Power amlifiers as in transiter / Mosfet / intergrated circuit ( black chips with legs)
Power Supplies - the unit that cghanges the voltage from the main supple and smooths it out.
Speaker Boxes - The box that make the noise this is very important as a qulity amp can sound crap on a bad speaker system for the room
Valve Amps - bring back the old days with tube that blow in the dark and get hot before you can use them.
The_Old_Lighting_Rig - light the room up man