NJD Electronics MA200 User Manual

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Features of the MA200

• 120 Watts RMS output per channel

• MOSFET output stage for greater clarity

• Over temperature monitoring

• Open & Short Circuit Protected

• Loudspeaker DC protection

• Peak and Normal indicators for each channel

• Individual gain controls

• Twin SPEAKON outputs per channel

MA200

Series 3

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IMPORTANT

Installer and Users please note:

These instructions should be read carefully and left

with the user of the product for future reference.

Installation

The MA200 must be installed by a competent electrician

in accordance with the current IEE wiring regulations.

Connect the MA200 to the mains supply (nominally 230V AC). If using a British 13 Amp mains plug (to BS1363A), fit a 13 Amp fuse in the plug. (If a 5A fuse is fitted in the plug it may fail due to the surge when the amplifier is switched on)

Connect the wires to the plug as follows:

• Brown = live

• Blue = neutral

• Green/Yellow = earth

• The MA200 must be earthed. NEVER disconnect the

earth, even in an attempt to prevent ‘hum’. If the earth were disconnected, it could result in equipment connected to the input (even indirectly through a mixer), such as microphones, becoming live in the event of a fault (such as a liquid spillage into the amplifier). The MA200 circuitry is only “loosely coupled” to earth so it is extremely unlikely to be the cause of a “hum loop”.

Install the MA200 away from sources of moisture; avoid areas where drinks can be spilled onto the amplifier as this may cause serious damage.

The MA200 requires a "line level" signal. This is the signal level from a mixer, a CD or tape player, or the audio output from a video player or satellite TV receiver. This signal level is generally referred to as 0dBm or 775mV. A signal from a microphone, electric guitar or turntable is not suitable; neither is the speaker output from another power amplifier, which may cause damage to the MA200 if connected to an input. A signal of 775mV RMS (0dBm) is required to achieve full power output with the volume controls set on maximum.

User Guide MA200

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Inputs

Connect the input signal to the ¼” mono jack socket on the rear panel. Use a screened cable for the input signal to avoid interference. If connecting from a stereo output, use a ¼” stereo jack plug to two ¼” mono jack plugs splitter lead. The input for the left channel is located towards the right of the amplifier when viewed from the back.

Two connectors are provided for each input, to allow the input signal to be connected to another amplifier as well, by connecting a mono jack-plug to jack-plug lead from the spare socket to the input of the other amplifier.

Outputs

Connect the speakers to the output Speakon connectors on the rear panel, using the 1/+ and 1/- terminals. Use a SpeakonSpeakon lead such as Electrovision WH430, WH431 or WH432, or a Speakon–female XLR lead.

A Speakon–¼" jack lead or a Speakon–male XLR lead MUST NOT be used with this amplifier, due to the risk of electric shock, (and is forbidden by the Electricity at Work Regulations)

Any number of speakers may be connected to each channel, as long as the combined impedance is not less than 4W. Two connectors are provided for each channel; the speaker loading applies per channel regardless of which of the two sockets are used. Connecting more speakers reduces the impedance. Connecting too low an impedance may damage the amplifier.

If one of the outputs is not being used, it is not necessary to connect any load to it.

"Speakon" is a trade-mark of Neutrik Ltd.

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For speakers connected in PARALLEL on each channel:

The following combinations MAY be connected

Speakers Combined impedance

1 × 16 W 16 W

2 × 16 W 8 W

3 × 16 W 5.3 W

4 × 16 W 4 W

1 × 16 W, 1 × 8 W 5.3 W

2 × 16 W, 1 × 8 W 4 W

2 × 8 W 4 W

1 × 4 W 4 W

The following combinations MUST NOT be connected

Speakers Combined impedance

5 × 16 W 3.2 W

3 × 8 W 2.7 W

4 × 8 W 2 W

1 × 4 W, 1 × 8 W 2.7 W

1 × 16 W, 2 × 8 W 3.2 W

2 × 4 W 2 W

Speaker Leads

Speaker leads should be chosen with care, especially with a high powered amplifier. Current carrying capacity is not usually a problem, but the use of too thin a cable can lead to loss of output. The table below shows the maximum cable lengths for a 10% loss in amplifier output. It is best to use a cable that is as short and as thick as possible. At the lead lengths shown below, 20W of the amplifier power is being lost, only 100W will reach the loudspeakers.

NEVER use screened lead to connect speakers to an amplifier, and never connect the output of the amplifier to a light controller with screened lead: use thin speaker cable.

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Cable size Maximum length for:

4 W load 8 W load 16 W load

0.5mm2 (WH152) 2.3m 4.6m 9.2m

0.75mm

3.5m 7.0m 14.0m

1.0mm

4.7m 9.4m 18.8m

1.31mm2 (WH153) 6.0m 12.0m 24.0m

1.5mm2 (WH130) 6.75m 13.5m 27.0m

2.5mm2

(WH130A,WH154) 11.4m 22.8m 45.6m

The WH430 (3m) and WH431 (5m) Speakon–Speakon leads may be used with any load impedance. The WH432 (10m) lead should only be used with a load 8W or higher, to avoid loss of power in the cable.

Ventilation

ALWAYS ensure that an adequate flow of cool air is available at the air intakes at the sides, and that the hot air can escape. If the amplifier overheats the speakers will be disconnected, and both green and red LEDs will go out. If the amplifier is adequately ventilated, this will not happen during normal use.

If the amplifier is installed in a cupboard, make sure that there is an adequate supply of cool air at the back of the amplifier.

The air vents should be cleaned periodically to remove dust and smoke fluid residues.

NEVER install the amplifier in a sealed cabinet.

Short circuit protection.

The MA200 is protected against short-circuits on the outputs. If this happens, it will limit its output current to a safe level until the short circuit is removed. A short circuit should be removed as soon as it is discovered, as the amplifier is not intended to be run indefinitely into a short circuit. Short circuit protection does not protect the amplifier from having too many speakers connected to the output.

If speaker leads are too long or too thin, their resistance may prevent the short circuit protection operating in the case of a short circuit at the loudspeaker end of the lead - in this case the

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impedance of the cable may be indistinguishable to the amplifier from a low impedance speaker.

Operation

ALWAYS connect the speakers and turn the volume controls to zero before switching on; do not touch the speaker outputs whilst the amplifier is running as this could result in electric shock.

Set the input level controls so that the red “peak” LEDs only illuminate on the loudest peaks when the levels on the mixer are at their highest setting.

If the amplifier is being asked to produce more power than it can supply it will ‘clip’ the signal, and if this happens the red LED will be illuminated. In this state, the amplifier can produce an output in excess of 180 Watts per channel at levels of distortion up to 30%, which could cause damage to speakers. This distorted signal has a large amount of extra treble which can damage high frequency units.

If the "peak" indicators are on excessively there is only one solution: TURN THE VOLUME DOWN.

Choosing loudspeakers.

If the amplifier is likely to be over-driven, then it is advisable to use speakers which can handle the extra power. Use a 180W 4W speaker, or, if two 8W speakers are connected to each channel, they should be rated at 90W each. Using a 120W and a 60W together may result in damage to the 60W speaker, as they will each receive 90W. NJD accepts no responsibility for damage caused to speakers by over-driving.

When choosing loudspeakers, always refer to the RMS rating, “music power” or “peak music power” ratings which are normally between two and four times higher than the RMS power capability, should be ignored. (The MA200 has a Peak Music Power Output (PMPO) rating of 570 Watts per channel)

When the MA200 is operating normally, the green LED will be illuminated.

If a fault occurs within the amplifier leading to a DC condition

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on the speaker outputs, the speakers will be disconnected before any damage can occur. If this occurs, consult a dealer.

Technical Specification

Dimensions: 19"×3½"(2U)×10" (483×88×254mm)

Weight: 6.9kg

Cooling: convection

Power output: 120W RMS into 4W

at onset of clipping 90W RMS into 8W

50W RMS into 16W

Max. Output voltage: 96V peak-peak.

Damping factor: 360 at 100Hz into 4W.

Output impedance: 0.025W

Input impedance: 10kW

Input sensitivity: 775mV (0dBm) for 400W into 4W

Frequency response: 15Hz to 30kHz ±3dB

Hum and noise: -93dB

Channel separation: 90dB

Harmonic Distortion: 0.1% at 90Watts into 4W

Intermodulation Distortion: 0.1% at 90Watts into 4W

at 50Hz and 5kHz Slew rate: 20V/µs Thermal shutdown: at 100°C power transistor temperature Power requirement: 230V AC 50/60Hz 800VA Fuse: T2A HBC 5×20mm to IEC127

(2 Amp ANTI-SURGE 5×20mm )

Connections:

Mains: IEC inlet connector Input: ¼" jacks Output: SPEAKON™ connectors.

1/+ signal

1/- ground

Standards

The MA200 complies with:

EN60065 (Electrical Safety), EN55103 (Electromagnetic Compatibility) and EN61000-3-2 (mains harmonic currents)

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Guarantee

This product is guaranteed for a period of 12 months

against faulty components or manufacture from the date of purchase. Upon proof of purchase, NJD shall, at its own option, repair or replace the defective item at no cost to the purchaser.

This guarantee is contingent upon the proper use of the

product in the application for which it is intended and does not cover products that have been modified, subjected to unusual physical conditions, or electrical conditions outside its specification, or damaged in any way.

This guarantee is limited to the product only and does

not cover carriage costs, installation costs or travel expenses. Your statutory rights are not affected.

In the event of any problems with this product contact

the retailer from which it was purchased for technical assistance, or e-mail [email protected]

NJD Products are distributed by:

Electrovision Ltd., Lancots Lane, Sutton Oak, St. Helens, Merseyside, England. WA9 3EX Telephone: +44 1744 745000

Fax: +44 1744 745002 E-mail: [email protected]

Neither the whole nor any part of the information contained

in, nor the product described in this User Guide may be adapted, copied or reproduced in any form except with the prior written approval of N.J.D. Electronics.

User Guide MA200

Web sites:

www.njd.co.uk

www.electrovision.co.uk