Patch Cords
Anyone have a good schematic for a Low-Z (Military Impedance) patch cord design? Preferably with a rheostat for adjusting the output volume. Thanks! I know we can just wire the headphone output straight into the comm cord, but it usually sounds like crap. I'd like to build something with a balanced circuit and something that won't draw too much current from the audio source.
Thanks! |
1 Attachment(s)
You need a resistor bridge. I made one years ago, with a little help from the electrics shop. :)
Your typical output from a phone, ipod, etc, requires an 8 Ohm load. Been a long time, but I think the input to the aircraft intercom is about 100 Ohms. Here’s a fixed system (assuming I have the intercom impedance correct...ask the avionics guys): |
1 Attachment(s)
If you wanted to put a volume control in the patch cord, I’d use a 50 Ohm fixed resistor, and a 50 Ohm variable resistor:
|
Thanks! My first just job as a reservist is building some patch cords, this is perfect.
|
Originally Posted by CowboyPilot79
(Post 2678108)
Thanks! My first just job as a reservist is building some patch cords, this is perfect.
|
The way I was taught/remember, in this example: if you are an 8-Ohm device, “looking” at your terminal connections on the patchbridge, you will see 8-Ohms as your closed loop.
If you are the 100-Ohm intercom, looking back at the output terminals, you see 100-Ohms in THAT loop. Easy in the fixed-volume bridge. For the variable, this “looking back” impedance could vary from 50-100. It would mean at zero resistance in the variable resistor (max volume), you’d have only 50-Ohms total in the bridge...might lead to some distortion, due to impedance mismatch. |
All times are GMT -8. The time now is 01:39 AM. |
User Alert System provided by
Advanced User Tagging v3.3.0 (Lite) -
vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.
Website Copyright ©2000 - 2017 MH Sub I, LLC dba Internet Brands