MA 2.2 TRUE CLASS A MICROPHONE AMPLIFIER. USERS MANUAL. MA 2.2 USERS MANUAL VERSION-1, MARCH 2000. CONTENTS COPYRIGHT BUZZ AUDIO 2000. PO BOX 6677, WELLINGTON, 6141 NEW ZEALAND. TELEPHONE 64+4+472-3084. http://www.buzzaudio.com email management@buzzaudio.co.
Welcome… Thank you for choosing the Buzz Audio MA 2.2 True Class A Microphone Amplifier. In this manual you will find important information regarding the use of your MA 2.2 and we suggest that you do read it before using the unit. If after unpacking the MA 2.2 you find any damage you should contact your dealer or supplier immediately for advice on what to do.
1] The Mains Input. As a safety precaution your MA 2.2 is shipped without a mains fuse fitted. Before use, you must select the correct mains voltage for your local supply on the rear panel and fit the correct mains fuse type into the fuse draw for that voltage. • Setting the Voltage Selector… You will need a flat blade screwdriver. If your mains voltage is 110V to 120V set the rear panel voltage selector to 120V. If your mains voltage is 220V to 240V set the rear panel voltage selector to 240V.
2] Connections. • Mic Input. The MA 2.2 is designed as a balanced input microphone amplifier. The connection of unbalanced sources is not recommended. The XLR female style input connector is wired as follows; Pin 1 = Signal Ground (common) Pin 2 = Signal Hot (+) Pin 3 = Signal Cold (-) • Output. The MA 2.2 has two output connectors. In standard configuration the output is unbalanced to avoid the extra amplifier stage required and maintain the shortest possible internal signal path.
3] Controls and Indicators. • O … REV Input phase reverse switch. In the up position the input is in phase with the output. In the down position the input phase is reversed. It is normal to hear a “click” when operating this switch. • 0dB … -20dB Input attenuator. In the up position the gain of the MA 2.2 is as marked around the GAIN knob. In the down position, a pad is inserted at the input, reducing overall gain by 20dB.
Controls and Indicators continued… • PWR … ON We recommend that your MA 2.2 remains powered whilst in regular use to maintain it’s excellent sonic performance. If you need to turn it off, this switch will do it. Down is ON by the way and the cool blue LED should light up. The audio outputs are automatically MUTED during power up and power down. • SIGNAL GROUND. This rocker switch on the rear panel selects HARD or SOFT internal signal grounding. In the HARD position, the MA 2.
4] Options. • Output Transformer. Mounting holes on MA 2.2 bottom panel behind the main channel circuit board are provided for fitting a Sowter type 8403-A line output transformer. Sowter transformers are made in England and can be purchased on line at http://homepages.tcp.co.uk/~sowter/ Buzz Audio can also supply the transformers pre-fitted to the MA 2.2 or as a kit for retro fitting. Soldering is required to fit the output transformer. For further information contact your dealer or Buzz Audio.
6] Service. Should you experience any technical problem with your MA 2.2, contact your dealer or Buzz Audio for recommendations on what to do. The modular nature of the MA 2.2 construction means most electronic faults can be easily repaired by swapping circuit boards. For on line support visit our web site; http://www.buzzaudio.com Buzz Audio, Rear Entrance, 77 Kent Tce, PO Box 6677, Te Aro, Wellington, New Zealand. Voice/Fax 64+4+385-2478. Email; management@buzzaudio.co.nz 7] Specifications.
8] Internal Adjustments. • The following information is provided should your MA 2.2 require re-calibration. All adjustments are performed in the factory and should not need re-adjustment unless the amplifier modules and/or other components have been replaced. You may wish to alter the PK LED threshold to a lower or higher setting. PLEASE NOTE – If in doubt, do not attempt any internal adjustments, seek technical help. Trim Pot Locater. MAXIMUM GAIN adjust. LOW FREQUENCY CMNR adjust.
Internal Adjustments • continued Initial Setup. See the previous page for the location of the trimmer pots. Set all front panel switches (except for the PWR obviously) to the UP position. Set the GAIN knob fully anticlockwise. The MA 2.2 should be powered up for 1 hour before making adjustments. All measurements are referenced to 0dBu = 0.775V RMS, (sometimes called 0dBm). • Maximum Gain Adjustment. Connect an audio voltmeter to the channel output to be adjusted.
9] Warranty Information. • Disclaimer Buzz Audio is not liable for any damage to microphones, amplifiers, consoles, speakers or any other equipment and/or electric shock to humans that is caused by negligence or improper installation and/or use of the MA2.2 True Class A Microphone Amplifier. • Standard Product Warranty Buzz Audio guarantees the MA2.
