I investigated the Heil Foster adapter and the shorted ring-sleeve is inside the 1/8 inch phono jack. Not in the easily fixed Foster plug. So it cannot be fixed...reasonably. Why short it making the adapter unusable for the excellent and reasonably priced gamer headsets?
Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles ________________________________ From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> on behalf of Robert Rennard via Elecraft <elecraft@mailman.qth.net> Sent: Monday, February 11, 2019 6:39 PM To: elecraft@mailman.qth.net Subject: [Elecraft] TRS connectors - Heil Foster adapter Chuck, KE9UW wrote = // You cannot use Heil's adapter for the front panel Foster 8 pin connector on the K3s because they short the ring to the sleeve for some unknown reason. So in order to use the K3s front panel 8pin Foster socket, you need to make your own Foster to stereo mini phone connector adapter. Only two connections and DX Engineering has an excellent Foster plug. Ignore the reference to Heil Replacement Part, it's just the same old Foster 8 pin plug for all mics and rigs. // The PC standard is for electret bias to be supplied to the tip and ring of a tip, ring, shield (TRS) connector with audio from the microphone entering the PC on the tip. The around 8 vdc bias is to be supplied via isolating TWO resistors, one to the tip and one to the ring. Low budget USB soundcard adapters use ONE resistor supplying bias voltage to both the tip and ring which are thus shorted together within the adapter. My Heil ProSet 3.5 mm microphone plug has no ring, just an extended sleeve. So, essentially the Heil microphone plug has the ring and shield shorted together, and the cheap USB adapter shorts the tip and ring, so inserting a Heil microphone plug results in the tip, ring and shield all being shorted together. The microphone would get no electret bias, and the audio it can’t produce is shorted to ground, too. On the other hand, good PC soundcards use TWO resistors and the Heil ProSet works fine with them! I believe in trust but verify. Chuck is correct, plugging a TRS aka stereo jumper cable into the 3.5 mm microphone jack on my K2/K3 Heil adapter and checking things with my Fluke DVM reveals that somewhere in the adapter the ring and shield are shorted together; maybe in the way things are wired, may be in the Foster plug. Continuing, with the K3 MIC-SEL sent to RPL-BIAS, at the rear-panel connector relative to the shield there is 7 VDC of bias applied to the tip, and the ring seems to float. With power OFF, the resistance between tip and shield was about 4.5 megohms and between the ring and shield even higher. Thanks Chuck, I learned something. It was a good day. Bob R – N7WY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to c-haw...@illinois.edu ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
