Ampetronic MP221 User manual

MP221
Microphone Preamplifier
The Lightning bolt triangle is
used to alert the user to the
risk of electric shock.
This symbol is used to alert the
user to important operating or
maintenance instructions.
Contents:
•Safety
•Introduction
•Installation
•Operation
•Troubleshooting
•Specification
•Accessories
•Warranty Information
•Declaration of Conformity
Box Contents:
1 x MP221
1 x 12
DC
Power Supply – region
specific
1 x 3-pole Jack output cable
1 x Handbook (this document)
Safety
1. It is important to read these instructions, and to follow them.
2. Keep this instruction manual in an accessible place.
3. No user serviceable parts. Refer all servicing to qualified personnel.
4. No objects filled with liquids, such as vases, shall be placed on the
apparatus.
WARNING: Do not expose to dripping or splashing.
5. Clean only with a dry cloth.

Introduction
The MP221 microphone preamplifier is designed for use with Ampetronic
Induction Loop drivers, but can be used in other applications as a separate four
input pre-amp.
The unit is designed to amplify two microphone channels by a maximum of 66 dB,
and two line-level inputs by 6 dB.
•Each XLR microphone channel has an electronically balanced input with
phantom power selected by a global switch.
•The balanced line-level inputs use 6.3mm (1/4”) 3-pole jack socket.
•Unbalanced stereo phone input is summed into a mono signal before
processing.
•A gain control is provided for each channel.
•The combined single channel (mono) output signal is electronically
balanced and is fed out on a 6.3mm (1/4”) 3-pole jack socket.
•Internal monitoring indicates signal ‘overload’ on front panel LED
•Power for the preamp is provided by the 12V
DC
adaptor provided.
Installation
The MP221 is designed to be freestanding, but can be mounted in combination
with many of the Ampetronic range of Induction Loop Drivers by using the RM-1U
rack mount kit with correct blanking plate(s).
Connect each input as required using screened cable with a balanced connection
where possible. Where phantom power for microphones is required, this must be
enabled using the ‘Phantom’ recessed slide switch on the rear of the unit.
Note: this is a global supply which with deliver phantom power to both
microphone inputs.
Each microphones channel gain can be individually adjusted by using an internal
jumper link to either 46dB or 66dB total gain. The unit is factory set to 66dB.
Connect the ‘Output’ to the line level input of the audio system.
Connect the power adaptor to the external power socket and insert into the DC
input. The green ‘Power’ LED should illuminate.
Operation
Adjust each of the front panel level controls to set the desired mix of signal inputs,
while ensuring that the red ‘Overload’ LED is never illuminated.
Note: There is no master output level control.

Troubleshooting
‘Power’ LED does not illuminate
•Check that the 12V DC supply is connected and switched on
No signal is heard further down the audio chain
•Check the audio source is producing signals, and is connected. If a
microphone is used, ensure that is the correct type, and that the 12V
phantom voltage is applied where required.
•Check that the relevant volume control is adjusted correctly.
•Check the output cable between MP221, and the next unit in the chain.
Signal is heard, but the ‘Overload’ LED is illuminated
One of the channels or the combined total of the inputs is creating a signal
level internally that is near to or actually clipping.
•Disconnect each input in turn and wait a few seconds to see if the
‘Overload’ LED goes out. If removing one of the inputs causes the
‘Overload’ LED to extinguish, then turn this channels gain down and re-
insert it. Slowly increase the gain to just below where the ‘Overload’ LED
comes on. Re-adjust all the other input levels compared to this to achieve
the desired mix. Note: Mic 1 and 2 channels have individual internal gain
links which can be set to reduce overall level by 20dB if required.
•Turn all output gains to minimum. If the ‘Overload’ LED is extinguished –
slowly increase the gain on each channel, and re-adjust all the other input
levels compared to this to achieve the desired mix – without causing the
‘Overload’ LED to be illuminated.
Specification:
Frequency Response:
20Hz - 20kHz
Mic 1 & 2: Balanced XLR Microphone inputs
Gain: +46dB / +66dB with gain control at maximum level
Input overload level: -26dBu
Input noise level: -124dBu 200Ωsource
Input impedance: 5kΩ
Phantom power: global selectable 12V
Line 1: Unbalanced summed twin phono inputs
Gain: +6dB with gain control at maximum level
Input overload level: +14dBu
Maximum unbalanced cable length 3m.
Line 2: Balanced / Unbalanced 6.3mm Jack Line level inputs
Gain: +6dB with gain control at maximum level
Input overload level: +14dBu
Maximum unbalanced cable length 3m.

Output: 6.3mm 3-pole jack socket for Bal/Unbal connection.
<0.01% THD @ 1kHz with +10dBu (10mW into 600Ω)
Minimum load: 600Ω
Maximum output level: +10dBu un-bal, +16dBu balanced.
The insertion of a 2-pole plug will unbalance the output, whist
maintaining the output level.
Environmental: IP30, -10°C to +45°C, 20 – 90% relative humidity
Dimensions: 200 x 108 x 44 (50 including feet) mm
610g (excluding power supply)
Power: 12V
DC
regulated 5.5/2.1mm power socket – centre positive.
Quiescent: 60mA
DC
0.72W
Maximum: 100mA
DC
1.2W
Use supply capable of delivering 150mA
DC
Regional AC-DC power convertor (No load) <0.25W
Maximum cable length 3m.
Accessories
Rack mounting tray, and blanking panels are available for the MP221.
See www.ampetronic.co for details.
Warranty Information
This product carries a five year parts and labour warranty from date of shipment
from Ampetronic. To qualify for the five year warranty, the product must be
registered at www.ampetronic.co (products/warranty), without which the warranty
will be valid for two years only.
The warranty could be invalidated if the instructions in this handbook are not
followed correctly, or if the unit is misused in any way. Note: The power adaptor
supplied with this product is only covered by the manufacturers warranty period.
The MP221 designed and engineered in England.
Declaration of Conformity
Manufacturer: Ampetronic Ltd.,
Address: Unit 2, Trentside Business Village, Farndon Road, Newark, NG24 4XB
Declares that the products: ‘Microphone Preamplifier’ Type Name MP221
Conforms to the following Directive(s) and Norm(s):
Directive 2004/108/EC EMC: EN 55103-1:2009+A1:2012
Directive 2006/95/EC Safety: EN 60065:2002+A12:2011
Directive 2011/65/EU RoHS
January 2016 – J.R. Pieters - Managing Director, Ampetronic Ltd.
Tel: [phone] Fax: [phone]
www.ampetronic.co Email: [e-mail]
UP13301
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