Clparker23 Posted January 4, 2019 Report Share Posted January 4, 2019 Does anyone have experience wiring a kx170 to a GMA 340 or 345? There are no “Lo” or “return” pins on the kx170. Are just the “hi” pins used making a single wire connection? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Mscheuer Posted January 6, 2019 Report Share Posted January 6, 2019 The KX170 is using airframe ground as the audio return, there are no wires to connect to the aircraft radio low that is indicated in the 340 or 345 connector. Hope this helps. Mark Scheuer PS Engineering 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 6, 2019 Report Share Posted January 6, 2019 Way to go Mark! There isn't a better resource / go to guy... for audio panels! Thanks for sharing your expertise. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Clparker23 Posted January 7, 2019 Author Report Share Posted January 7, 2019 Thanks mark, that’s what I thought, and that’s how I wired. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Dimmer Posted February 12, 2021 Report Share Posted February 12, 2021 On 1/6/2019 at 8:39 AM, Mscheuer said: The KX170 is using airframe ground as the audio return, there are no wires to connect to the aircraft radio low that is indicated in the 340 or 345 connector. Hope this helps. Mark Scheuer PS Engineering Saw this and had a question. Should the Lo pins on the GMA 340 then be tied to a ground connection, or left as N/C? Quote Link to comment Share on other sites More sharing options...
Dimmer Posted February 12, 2021 Report Share Posted February 12, 2021 Saw this and had a question. Should the Lo pins on the GMA 340 then be tied to a ground connection, or left as N/C? Quote Link to comment Share on other sites More sharing options...
Minivation Posted February 12, 2021 Report Share Posted February 12, 2021 (edited) 2 hours ago, Dimmer said: Saw this and had a question. Should the Lo pins on the GMA 340 then be tied to a ground connection, or left as N/C? The LO pins should be connected to airframe ground, preferably along with the KX170B's power ground or as physically close as possible to to the KX170B's power ground in order to avoid annoying ground-loops. I've attached a wiring diagram of an installation I did between a KX170B and a PS Engineering PMA8000 I did a few years back. With the LO->GND arrangement shown, the audio quality was excellent. Within the scope of Comm1/Comm2/Nav1/Nav2 audio wiring, the pinouts between the PMA8000 and GMA340/345 are identical. Be advised: The KX170B requires its speaker output to be utilized one way or the other. If your airplane has a cabin speaker, then chances are it will be interfaced to the audio panel's speaker output, not the KX170's. In such a case, the KX170's own speaker output (P171 Pin 6) will need to be connected to a load resistor, preferably 16-Ohms, 3W (or greater) otherwise, damage to the radio may occur. Example load resistor suggestion: https://www.alliedelec.com/product/vishay-dale/cw00516r00je12/70204759/ KX170B PMA8000 Interconnect Excerpt.pdf Edited February 13, 2021 by Minivation 1 Quote Link to comment Share on other sites More sharing options...
Dimmer Posted February 13, 2021 Report Share Posted February 13, 2021 Thanks..Very useful. 1 hour ago, Minivation said: The LO pins should be connected to airframe ground, preferably along with the KX170B's power ground or as physically close as possible to to the KX170B's power ground in order to avoid annoying ground-loops. I've attached a wiring diagram of an installation I did between a KX170B and a PS Engineering PMA8000 I did a few years back. With the LO->GND arrangement shown, the audio quality was excellent. Within the scope of Comm1/Comm2/Nav1/Nav2 audio wiring, the pinouts between the PMA8000 and GMA340/345 are identical. Be advised: The KX170B requires its speaker output to be utilized one way or the other. If your airplane has a cabin speaker, then chances are it will be interfaced to the audio panel's speaker output, not the KX170's. In such a case, the KX170's own speaker output (P171 Pin 6) will need to be connected to a load resistor, preferably 16-Ohms, 3W (or greater) otherwise, damage to the radio may occur. Example load resistor suggestion: https://www.alliedelec.com/product/vishay-dale/cw00516r00je12/70204759/ KX170B PMA8000 Interconnect Excerpt.pdf 43.16 kB · 3 downloads Quote Link to comment Share on other sites More sharing options...
carusoam Posted February 13, 2021 Report Share Posted February 13, 2021 Welcome aboard Dimmer and Minivation... a day late... Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
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