Ever Connected a David Clark Aircraft Headset to Transceiver?

[N4GRF]

I have a David Clark H-10-56 headset from the days when I flew aircraft. The headset is an excellent piece of equipment, and I was wondering if any of you Elmer s knew how to connect it to a modern solid state transceiver. I recall that it requires some small voltage DC applied to the microphone circuit to power the mic amplifier module. I'm not sure how much. David Clark is not helpful on explicating their designs.

Most modern transceivers have 8v dc pins on the mic connector (Pin2 on the ICOM 756) which can provide the "phantom" power to the David Clark unit. I'm not certain the voltage requirements of the headset, and I thought of  inserting a small resistor in series with the DC to guard against damaging the amplifier module.  Anybody have a any experience with these headsets?

Kindest regards, and thanks, Tom N4GRF

[KG4RUL]

The David Clark headsets will operate with a 5-15VDC supply for the amplifier.  This is a possible circuit - use at your own risk.
http://www.kg4rul.info/DavidClarkAdapter.bmp

[N4GRF]

Dennis: that was the one I was looking for.  Thank you so much. I couldn't recall the back-to-back electrolytics. Very best regards to you, Ann and KBIRD.

73, Tom Gallagher N4GRF (formerly of Charlotte NC).

[WB4SPT]

I just made up this circuit, using a Telex aircraft headset.  I get about 75mv ac at the mic plug.  Is this enough to drive a Drake T4x?  The manual only calls for a high Z mic, no mention of voltage level.  My T4x is down right now, and I can't test myself, just yet.
73's

[VK2HLG]

Thanks, KG4RUL, for posting that schematic. I'm planning to build an adapter as well.

I'm pretty much a rookie at this, so please pardon some questions.

1. My headset is a David Clark H10-13.4S, which has a mono/stereo switch on its cable (which I believe affects only the earphones). As well, it has what appear to be four conductors on the microphone plug (the plug is a PJ-068 [.206-inch phone plug] type). This confuses me, because your schematic shows only three connections, and also because the only .206-inch plugs I can find show three connections as well. This drawing refers:

http://www.switchcraft.com/Drawings/S13B_CD.pdf

This is a photo of my headsets plugs. The microphone one is in the foreground:

http://i292.photobucket.com/albums/mm1/hazydavy99/DSC_0657.jpg

Can anyone explain how a four-conductor microphone plug corresponds to KG4RUL's schematic?

2. I tested the pins on the 8-pin microphone connector on my IC-7200 and found that pin 2 delivers 9 VDC, rather than the 8 VDC specified in its schematic.

This is okay, right? KG4RUL stated that the David Clarks want 5-15 VDC. Is that on the David Clark site somewhere?

Thanks.

VK2HLG

[K0IZ]

QST, April 2010 Hints and Kinks for circuit that matches impedance and levels.

[KG4RUL]

Thanks, KG4RUL, for posting that schematic. I'm planning to build an adapter as well.

I'm pretty much a rookie at this, so please pardon some questions.

1. My headset is a David Clark H10-13.4S, which has a mono/stereo switch on its cable (which I believe affects only the earphones). As well, it has what appear to be four conductors on the microphone plug (the plug is a PJ-068 [.206-inch phone plug] type). This confuses me, because your schematic shows only three connections, and also because the only .206-inch plugs I can find show three connections as well. This drawing refers:

http://www.switchcraft.com/Drawings/S13B_CD.pdf

This is a photo of my headsets plugs. The microphone one is in the foreground:

http://i292.photobucket.com/albums/mm1/hazydavy99/DSC_0657.jpg

Can anyone explain how a four-conductor microphone plug corresponds to KG4RUL's schematic?

2. I tested the pins on the 8-pin microphone connector on my IC-7200 and found that pin 2 delivers 9 VDC, rather than the 8 VDC specified in its schematic.

This is okay, right? KG4RUL stated that the David Clarks want 5-15 VDC. Is that on the David Clark site somewhere?

Thanks.

VK2HLG

The specs for the David Clark H10-13.4S headset indicate:

Earphone Plug:    PJ-055 (.25" phone plug)    Mic Plug:    PJ-068 (.206" phone plug)

http://store.acousticom.com/aviation-connectors-pj-068pj-055

Both of which are three conductor plugs.  Could your four conductor plug be a replacement installed for a specialized application?  Though your photo seems to show a molded plug.

[VK2HLG]

It definitely has four segments. I tested them with a continuity meter.

Though the unit is more than 10 years old, it's never been modified.

My guess is that one of the rings is not used. I will plug it into a standard PJ-068 jack and just use its outputs.

[K7RBW]

http://www.aeroelectric.com/articles/micjack/micjack.html

Has a good picture & explanation of the mike plug's connections.

I'm guessing the unused conductor is there to prevent shorting (which could key the transmitter) when inserting and removing the connector.

[KB4QAA]

Yes, the extra segment is just a spacer.  It's standard aircraft plug that is also used in older ham transmitters.