Question:
Is the gain control on my amplifier really a volume control?

Answer:
NO! The gain control matches the RCA output voltage of your source unit to the input circuits of your amplifier. Your system gets louder when you turn the control clockwise because as you turn up the gain, the amplifier inputs become more sensitive and will look for more things to amplify such as alternator whine, ignition tick and hiss. Keep this control as low as possible. The volume of your system is directly proportional to the amount of power and speakers you have. For example: if you crank the gain all the way up you may only be able to turn your radio up to volume 15 by the time it as loud as it can get but with the gain set properly you should be able to get the volume up to approximately ¾ of full volume so you will have a more usable range of power.