Henry Engineering MIKE ALERT Users Guide

MIKE ALERT

HENRY ENGINEERING

Microphone Tally Light Controller

www.henryeng.com

PO Box 3796

Seal Beach, CA 90740

Tel: [phone]

DESCRIPTION

Mike Alert is an interface unit for controlling the dual-color tally lights on “MIKA” microphone arms. The Mike Alert

unit allows two mic arm tally lights to be independently controlled, and provides power and control circuitry to
operate the white and red tally indicators in each mic arm.

WARNING! For 230V operation, change mains voltage jumpers before connecting to AC power!

Remove jumpers between E6 & E7, and between E5 & E8. Install a jumper between E5 & E6 for 230V; replace
fuse with a .125a fuse. See schematic on reverse side. Jumpers should be changed by a qualified technician only.

INSTALLATION

Connect each MIKA mic arm to the 5-pin female XLR Input connector. Wire the cable from the MIKA mic arm to a
5-pin male XLR connector as follows:

Pin 1 = Mic ground (Ties to Pin 1 of Mic Output connector)
Pin 2 = Mic audio + (Ties to Pin 2 of Mic Output connector)
Pin 3 = Mic audio – (Ties to Pin 3 of Mic Output connector)
Pin 4 = Tally light BLACK wire
Pin 5 = Tally light ORANGE wire

Note: Mic audio will be passed-through to the 3-pin male XLR Output connector on the Mike Alert unit.
All tally light control inputs are via the 15-pin D Control connector. There are two inputs for each mic arm. One

input activates the WHITE tally light, the second input activates the RED tally light. All control inputs are opto­isolated. Control inputs can be either a maintained DC voltage (5-12 vdc) or a contact closure or open collector.

For control via maintained DC voltage, connect to the + and – input terminals only. (Input Z = 2k ohms)

Pin 1: MIC 1 WHITE + Pin 5: MIC 2 WHITE + Pin 9: +12V SOURCE Pin 13: +12V SOURCE
Pin 2: MIC 1 WHITE - Pin 6: MIC 2 WHITE - Pin 10: GROUND Pin 14: WHITE Output
Pin 3: MIC 1 RED + Pin 7: MIC 2 RED + Pin 11: +12V SOURCE Pin 15: RED Output
Pin 4: MIC 1 RED - Pin 8: MIC 2 RED - Pin 12: GROUND

For control via an external contact closure or open collector, connect the + input(s) to any +12V SOURCE pin.
Connect the closure between the – input(s) and any GROUND pin. (The external contact closure completes the
circuit to ground, using the Mike Alert as a power source.)

Pins 14 & 15 are “master outputs” for the WHITE and RED tally indicators. These outputs provide 12 vdc whenever
either the white or red tally outputs is active. These outputs can be connected to a Henry Engineering
SUPERELAY to activate the studio’s main On The Air tally light. If multiple Mike Alert units are used, these outputs
can be bused together so that the main On The Air light will turn on when ANY microphone is in use. Connect Pin
14 and/or Pin 15 to the Superelay’s IN+ control input. Connect any GROUND pin of the Mike Alert to the Superelay
G input.

OPERATION

Mike Alert will activate the MIKA tally lights when it receives a control input. All inputs must be maintained (not a
momentary pulse). Note that the RED input will always take precedence: if the WHITE and RED inputs are both on
at the same time, only the RED tally light will operate. The LEDs on the front of the unit will indicate which tally
lights are active. (Yellow LED = WHITE; Red LED = RED)