Welcome to the FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
Need the latest SmartSDR or 4O3A Genius Product Software?
SmartSDR v4.1.5 | SmartSDR v4.1.5 Release Notes
SmartSDR v3.10.15 | SmartSDR v3.10.15 Release Notes
The latest 4O3A Genius Product Software and Firmware
If you are having a problem, please refer to the product documentation or check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

6300: Mic input circuit, actual impedance?

Jim KJ3P
Jim KJ3P Member ✭✭✭
edited April 2020 in FLEX-6000 Signature Series

When interfacing a mic that has an internal transformer for its (250 ohm) output, it's important to know the actual impedance that the transformer will "see" to assure that the transformer is properly terminated.  Anybody know what actual input impedance is presented by the 6300's mic pre-amp?

Another way of posing this question is:  what kind of load does the radio present to the mic? The specs say:  Microphone Impedance:  600 Ohms Nominal (200-10kΩ). This suggests that the input impedance is high, otherwise a 10K mic might be loaded down too much, but it's just a guess.

Answers

  • Paul Christensen, W9AC
    Paul Christensen, W9AC Member ✭✭
    edited June 2019

    A quick check of the schematic diagram would provide the information we need.  Are schematics of the Flex 6000 series available?  I'm interested not just for this reason but to better understand the internal relationships of the Flex 6K hardware.

    Paul, W9AC   

  • Gerald-K5SDR
    Gerald-K5SDR FlexRadio Employee ✭✭
    edited April 2019
    The microphone inputs are high impedance.  The actual impedance varies by the gain setting of the DVGA in the CODEC.  The minimum impedance at maximum gain is about 5k on the front panel mic and about 3k on the balanced input.  The maximum impedance is over 80k at minimum gain settings.  
  • W5XZ - dan
    W5XZ - dan Member ✭✭
    edited December 2016
    me too!  w5xz, dan

  • Jim KJ3P
    Jim KJ3P Member ✭✭✭
    edited April 2020
    Just what I needed...thanks!

Leave a Comment

Rich Text Editor. To edit a paragraph's style, hit tab to get to the paragraph menu. From there you will be able to pick one style. Nothing defaults to paragraph. An inline formatting menu will show up when you select text. Hit tab to get into that menu. Some elements, such as rich link embeds, images, loading indicators, and error messages may get inserted into the editor. You may navigate to these using the arrow keys inside of the editor and delete them with the delete or backspace key.

Comment As ...

Categories