Knoll MA225E User Manual

Warranty

Inputs

Gold RCA jacks with adjustable gain

Input impedance

55k ohms

Outputs

Detachable 4 position connector

Output power

25 watts RMS per channel (4 ohms)

Peak output power

30 watts per channel (4 ohms)

Ideal impedance

4 - 8 ohms

Frequency response

10 Hz - 20 kHz +/- 1dB (1w)

THD distortion

less than 1% 20 Hz to 20 kHz

IMD distortion

less than 0.5% 60 Hz 7 kHz 4:1 (SMPTE)

Dimensions

6-3/8” x 2-1/2” x 2-1/4” h (162x64x57mm)

Weight:

¾ lb. (0.35 kg) without power supply

Power

30VDC at 1800mA

Knoll Systems warrants MA225e Amplifiers sold in the USA and Canada by
authorized Knoll dealers to be free of defects in materials and workmanship.
This warranty extends for three full years from the date of purchase by the
original consumer. Any products returned to Knoll Systems and found to be
defective by Knoll Systems within the warranty period will be repaired or
replaced at Knoll Systems option, at no charge. Knoll Systems will not be
responsible for the actual cost of installation or removal of the product, nor for
any incidental or consequential damages. Some states do not allow the
exclusion or limitation of incidental or consequential damages, so the above
limitation may not apply to you. This warranty gives you specific legal rights.
You may have additional legal rights that vary from state-to-state.

Specifications:

Knoll Systems

145 Tyee Drive Point Roberts, WA 98281
12140 Horseshoe Way, Richmond, BC V7A 4V5
Tel: [phone], fax [phone]

Made in Canada

MA225e
Amplifier

Eco-System Wall Mount Stereo Amplifier
Installation Instructions v1.2

Warning: To be installed and/or used in accordance with appropriate

electrical codes and regulations.

Description: The MA225e amplifier is a 25-watt per channel high­fidelity stereo amplifier. Stable from 2 to 16 ohm loads, the MA225e
integrated amplifier features a volume/gain, bass, treble and balance
controls. MA225e amplifier is designed to meet the amplifier needs of
custom installed systems where high-quality sound is a specific
requirement.

 Small size, really big sound. Fits almost anywhere.
 Stereo amplifier has 25 watt per channel rating.
 Each channel is protected from overheating,

overloading, overvoltage and undervoltage. The
protection circuitry automatically restores the amplifier
channel as soon as its parameter returns to the safe
operating area.

 2-16 ohms stable. Goes with almost any speaker.
 Eco-System circuit turns amp off when not in use.

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.