Headset compatibilty

[SE7EN]

Can anyone please tell me if a military spec plug, U-174/U plug, is compatible with a standard civil helicopter socket?

Many thanks:

[spinwing]

That kinda depends .....

The U 174/U is also known as a NATO socket and should be compatible with anything coming from the USA.

If your Heli has been in the UK ... their NATO socket is different (go figure?).

Cheers :(

[SE7EN]

Thanks spinwing. The headset and the chopper are both in the USA.

Should be ok then I guess.

Thanks again

[Gomer Pylot]

The plug is compatible, but the electronics in the headset may not be. Any plug can be put on any headset, but that doesn't mean it will work. The standard in the USA is 300 ohm speakers, and electret mikes are nominally 50 ohms. Standard military electronics won't work, because the speakers are nominally 8 ohms, and the mikes are about the same. You can hear using military headsets if you turn the volume way up, but the mike won't work. All that may be more than you wanted to know, and less than you already knew, but I don't know what you knew, or when you knew it. :8

[Lightning_Boy]

I have a simular problem. Got a David Clark H10-56 (with the ANR). Bought the headset in the states, on return to the UK, I wasn't sure if it would work. However, worked fine on the AS355 but not on the AS332? Could hear, but mic wouldn't work. Couldn't figure that one out. Surely if it works in one, it should work in the other? :ugh:

Any guesses welcomed :ok:

[spinwing]

Mmmm...

'fraid not ..... think you'll find that the AS355 avionics will be compatable with the Electret mike set up that is the standard with Dave Clarks.... when you get into the "Big Toys" you might find things different with the M87 type Dynamic mike required by the avionics fit .... the only way to know is to check with the "queer trades" guys in the avionics shop!

I have for years carried two types of mikes for my helmets/headsets which I change as required depending on which bit of kit is required.

As a rule (subject to retrospective change ...of course!) most civvy aircraft will have avionics set up for 300-700 ohm phones impedance (Mil a/c usually 8 ohm).

The mike requirement may be set up for "Dynamic Mike" (unamplified) at the headset because the avionics fit already has the mike amp fitted in the system. ..... OR it may be set up for an Electret type/Dynamic mike unit amplified at the headset.

Note: Dave Clark actually make a headset that will handle both setups via a small switch on the earcup which activates/de-activates a mike amp fitted to the headset. ... think its the H10-66

Cheers ;)

[Lightning_Boy]

Thanks Spinwing. Makes sense now! I'll call DC's and find out the cost of a mic conversion.

Big Ta, LB :ok: