Amp lingo,

Why some amps use diferent words but basicaly they mean the same thing,for example i'm reading some postings and almost everywhere the sugestion is to turn the GAINS right down,ok;but my amps use a diferent word for it INPUT SENSITIVITY,is the same as Gains,please clarify this .The amps i'm refering to are Nakamichi's and the input sensitivity ranges from 7.5 V to 0.2V.I'm using a PPI eq that has line driver build in (ppi-eqp).Can somebody tell me where my seting should be at.

Thank you

The CORRECT term is actually "input sensitivity" as your amps say.  Also correct would be "input stage gain".  The simple term gain is misleading as that control on ANY amplifier is really input sensitivity.  (Real AMPLIFIER gain is not adjustable on any car amp I've ever seen).  Still far too many amp manufacturers use the word "gain" on amps.

Therefore "gain" is NOT a volume control, rather it is a control used to match the input level to the amp.

What is being "gained" or adjusted for is a difference in input on the RCA (or speaker-level) inputs on the amp.  The simplest form of input sensitivity adjustment is the "by-ear" method which goes like this:

1.  Turn the gain on the amp being set-up all the way down (the HIGHEST voltage if voltages are given; also almost always the most anticlockwise position).

2. Turn the HU or source volume to maximum and listen for any source unit induced distortion.  If any HU distortion is present back off the volume a few points until it is gone.

3.  Then begin turning the input sensitivity control up until you can hear distortion.  Back the control off a bit until the distortion subsides.

Continue this procedure for all amps/channels in the system.  (Hearing protection might be a good idea if you are going to be encountering high sound levels).  You have now set the system for maximum S/N and the most useable range of volume control from the HU.

Also note that since you are using a line driver, you might not have to turn the gains very high at all, perhaps you might leave them at the lowest setting (7.5V) if necessary as some line drivers put out very high voltages.