Headset Helicopter -> GA conversion adaptor

[McWho]

Hi all, wasn't sure where to post this but hope someone can help. I've just picked up an H10-56HX headset which is designed for helicopters but I'm going to be requiring an adaptor for fixed wing with GA jacks. Can anyone tell me if I will also require an impedance conveter for this unit also? I'm also having trouble being able to tell if the unit is supplied with the UK NATO or US NATO plug, so if anyone could offer some insight there it would be much apprecaited.

If impedance is required, is it required for the headphones or mic, or both? Could I simply make my own with a pot of a few kilo-Ohms?

I've scoured the internet and can't find much information, so any help is appreciated.

[roljoe]

Hi,

normally the inpedance modification only concerns the audio part of it..

suggest you check the "david clarck" web site..where you should find a lot of modification kit..

anyhow, a deep verification should be done by an avionic's technician to be sure about this on the plane and installation on which this is intended to be used..

Don't play with this kind of stuff..

rgds

[411A]

Generally, the impedance of the mic and headphones will not be a particular problem...however, some headsets have a built in mic amplifier which is specified in certain helicopter installations...and these can definitely present a problem in certain circumstances.

Beware.
Consult the audio tech for confirmation.

PS: This is also true in some jet (fixed wing) aircraft.

[McWho]

Thanks for the advice guys, I've looked at the prices of cables and I think they're a bit of a rip off for what they are, does anyone know where I can pick up the following in England to make my own:

1 x TJ-101 (U-174 socket)
1 x PJO68 (.206" Mic Jack)

Thank you

[Rotorhead1026]

1 x TJ-101 (U-174 socket)
1 x PJO68 (.206" Mic Jack)


http://www.davidclark.com/HeadsetPgs/h10-56.htm


I dunno what the "HX" means ...


Agree with you on the price of adapters - and they're usually too long!

If you're going to have an avionics guy look the thing over, then he (or she) might well have these plugs handy. It's be a shame to run all over trying to find these and wind up with the wrong ones - it's easy to do, even if they seem to fit the headset (voice of experience!)

[McWho]

This is the spec for the HXL which looks similar to the photographs of the unit I picked up:

http://www.davidclark.com/avHeadsetSpecs/avSpecs.aspx?ModelName=H10-56HXL

It says M7-A amplified electret microphone, which is the same used across their ENC range, including the one with the GA plugs.

The link you supplied above says amplified dynamic microphone. So you can see why I'm getting a little confused when it comes to impedances. I'm going to pick my headset up tonight so hopefully I'll be able to tell what's going on a little better.

[Rotorhead1026]

Yeah, the one I was looking at was a much older model. I can only say that my older DC headsets (with electret mikes) work fine in both GA airplanes and Hughes piston helicopters. Good luck with yours ... it'll probably be fine.

[McWho]

I've had to bite the bullet and fork out £35 (inc delivery) for the US NATO -> GA adaptor. Cheapest I could source the individual jacks for was around £7 mark. I think it's an absolute disgrace at that price. I've even had one company try to charge me £5+ for the 1/4" standard audio jack you can get down at Maplins for £1.50 (which is pretty expensive anyway!).

These aviation companies are pretty extortionate. But it's better than forking out ~£60 + ~£40 then who knows how much import tax for David Clarks own adapter. For a piece of wire with 3 plugs on they must think their customers are mugs.

[McWho]

:E Happy to report that the straight through cable worked, and the headset unit is hi impedance as required for most GA aircraft.

[Mark 1]

Sorry I saw this too late, but Adams' at Biggin Hill have the adaptor cables and even mic. impedance matching boxes.

For future reference.

[gigi116]

Standard in civil aviation Radio is carbon or "electrect" microphones.
some helicopters radio (most military) works with dynamic microphone.