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PANEL MICROPHONE PRE-AMPLIFIER:

June 6, 2011

This device is called “pre-amplifier”, which allows to us to obtain more gain and volume in the uplink audio. This device works in parallel with the potentiometer included on the amplifier, therefore, with this, you will have two potentiometers to control the volume and for balancing the audio.

PANEL MICROPHONE PRE-AMPLIFIER:

Introduction:

Sometimes, depending on the installation and the environment where it is installed, the uplink audio does not arrive with enough audio volume to the apartments, in spite of setting the potentiometers to the maximum value in the amplifier. In these cases, it is possible to add a device in order to increase just the uplink-audio volume.


This device is called “pre-amplifier”, which allows to us to obtain more gain and volume in the uplink audio. This device works in parallel with the potentiometer included on the amplifier, therefore, with this, you will have two potentiometers to control the volume and for balancing the audio.


Now, we are going to explain how to make and mount this pre-amplifier in the panel.

 

Arrangements:

  • 1 x Circuit FS10120CI01A Mic. Electret              Cod. 95157
  • 1 x Cable 15203CB02A                                     Cod. 93778
  • 1 x 2 Pin Connector JST B2B-PH-SM4-TB         Cod. 91951

 

 

How to make:

  1.  Desoldering and removing the electret microphone on the circuit 95157

  1. Soldering the 2 pin connector as you can see in the picture. Please, pay attention on the position of this connector on the PCB

  1. Soldering the cable 93778 to the PCB following the next instructions:
  •  The red wire is soldered to the M pad.
  •  The black wire is soldered to the M' pad.

 

Mounting on the panel: Cityline

  1. Disconnect the original panel microphone from the amplifier (unplug the connector).
     
  2. Connect the cable from our module (the 2 vias cable) to the MIC connector on the panel amplifier.
     
  3. Connect the panel microphone (the unpluged connector) to the connector in our module, which we had soldered previously.
     
  4. Put the amplifier module in a safe place to avoid short-circuits with other cables or components. Use adhesive tape for this. Remember to leave the potentiometer uncovered in order to be able to set the gain (the audio level that we want to get) of our pre-amplifier easily.

 
   

Mounting on the panel: City Classic

In this case, you have no connector at the microphone. Therefore you have to solder the module wires directly to the PCB of the panel amplifier, or put the corresponding connectors manually: female connector in the microphone wires and male connector on the PCB.

However, the philosophy is the same: Bypass the panel microphone through the pre-amplifier module to increase the signal level, controlled by a potentiometer.

  1. Open the CityClassic amplifier to see the PCB

  1. Bypass the microphone through the pre-amplifier module.

Conclusion:

The pre-amplifier module, which has been shown in this article, is very useful when you want to have more audio volume in the apartments from the panel.

The pre-amplifier module can be used in any Cityline Panel, in any version and in any system (ADS, 4+N, BUS2) just plugging the pre-amplifier to the microphone input of the panel. Moreover, you can also use it with the CityClassic panels, but in a different way: soldering directly the pre-amplifier module to the PCB.

Nevertheless, the philosophy is the same: Bypass the panel microphone through the pre-amplifier module to increase the signal level, controlled by a potentiometer.

It is possible to find more information about this device on the following link:

http://docweb.fermax.com/docs/descargas/TEX_APNOTE_PreAmplifier_Module.zip