Inputs – Directed Electronics MA4100 User Manual
Page 10
8
I n p u t G a i n C o n t r o l s
There are two Input Gain Controls located on the end panel under the RCA input
jacks. These are not volume controls! These controls match the output signal
voltage of the source unit to the amplifier inputs.
By turning the controls clockwise (to the right), the inputs of the amplifier become
more sensitive and will allow a weak signal of approximately 1/2 volt to drive the
amplifier to full power. At the same time, while an amplifier with its level controls at
maximum is able to drive a weak signal, it also picks up and amplifies any noises
lurking in the background, such as a brake light
pop, alternator whine, or ignition
tick.
Increasing the signal voltage to the amplifier by using a high output source unit, or
a TUBE DRIVER LD-3, will increase the signal to noise ratio . By turning the level
controls counterclockwise (to the left), the amp inputs will be less sensitive. The
amp will reproduce music at full power while making any noise floor insignificant.
Your
MA4100 accepts signal levels of up to 12 volts RMS.
S e t t i n g I n p u t G a i n
1. Set the Input Gain Controls to just above the lowest setting.
2. Turn the master volume on the source unit or pre-amp to almost full volume.
3. With music playing, slowly increase each Input Gain Control until you hear
distortion. Turn down each Gain Control until the distortion stops.