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Installation
The MA225e amplifier does not have to be near the stereo
equipment but long line level audio runs are not recommended.
It is better to have long speaker wire runs rather than long line
level source audio wire runs.
If long line level audio runs are required, we suggest using the
Knoll UTP stereo balun balancing system to avoid electro
magnetic interference. Avoid installing the MA225e amplifier in
high heat or humidity areas.
Connect the stereo source to the MA225e gold RCA jacks
labeled INPUT using good quality short as possible RCA jack
wires.
Connect the speakers to the MA225e using good quality 18-12
gauge wires. If the wires are mounted inside a wall, fire rated
wire may be required. Speaker polarity is important. Wrong
polarity or out of phase speaker wiring will make the bass
response of the speakers poor. Carefully check that the + of
speakers are connected to the + of the MA225e terminals.
Connect the power supply to the MA225e power jack. If the
stereo source has a switched outlet we suggest plugging the
power supply into the switched outlet.
Plug the power supply or supplies into the wall. After the
system powers up and the source is on and running, adjust the
volume/gain and on the MA225e adjust the balance, bass and
treble as needed.
The sensitivity adjustment on the side of the amp lets the
amp know when to turn on and off. If the line noise is high the
sensitivity should be adjusted a tiny bit up so when no signal is
present the MA225e turns off within a minute of not playing
anything.
Operation
Turn the source on and confirm it is operating.
Turn the MA225e on by plugging in the power supply or
switching the power supply on.
When the MA225e is playing something the led should be on.
Within a minute of not playing anything the led should turn off.
Use the MA225e volume to turn the volume to the correct level.
Adjust the MA225e bass, treble and balance as desired.
Note: The MA225e amp may be hot to the touch after
operating for some time. This is normal.
Knoll Systems service information
The MA225E amplifier does not contain any user serviceable parts
inside. If you suspect a problem that may require servicing, contact us
at www.knollsystems.com/contact.html, or by phone at 800 566-5579.
Troubleshooting
If a problem is encountered with the MA225e amp, the most
expedient procedure is to locate the problem and if possible
repair it before requesting service. Be sure to carefully check
other system components such as controllers, CD players,
volume controls, wiring, speakers, etc. that may be at fault.
Problem Action
Power LED does 1. Check that the amp power supply is
not light - no sound plugged in.
2. Test the AC outlet with a lamp.
Sound cuts out 1. Verify speaker impedance is 2-16
ohms. Changing speakers may be required.
2. Check if the MA225e feels hot. If it's
hot increase cooling.
Sound is distorted 1. Turn the volume down.
2. Check speakers for damage.
3. Check inputs for proper levels.
MA225e gain and source output level
may have to be adjusted.
4. Speakers may be less than 4 ohms.
Speaker pops when 1. Speaker may need resistor placed
amp turned on or off across terminal. Suggest 2k0 1/4 w.
This resistor discharges the speaker
internal capacitor.