Bose A20 high/low imp vs. separate Impedance converter

[Reely340]

Training is happening on S-300C, buddy has access to BO105 and EC135.
Reportedly this puts me into microphone impedance hell.
Hence I've some questions for the experienced Rotorheads here.

1. Is it correct that it is only the mic's impedance that is of concern?
2. GA vs. mil., who's got low and who's got high imp?
3. S-300C, BO105, EC135 what impedance each?
4. anyone got experience with "single headset + imp.-converter" configuration?
5. which works better low imp. head set + low2high conv. or the other way round?
6. Is DavidClark's H10-66XL the cure (on par with A20, noise cancelling and wear comfort wise)?
7. Are there Bose A20 mic impedance conversion kit out there (just swapping the mic)?
8. Anyone got results with Hi-Lo Imp.Adaptor

fire away, thx in advance

Peter

[Adroight]

If you have a Bose A20 and want to fly low and high impedence helicopters you simply need to have interchangeable mics - not 2 headsets.

[Reely340]

Heard that one before. Rumor has it only the non-bluetooth accepts(?) / offers both kinds of microphones.
Got any pointers for me, what (Bose spare part no?) one should get to end up with one A20 for both worlds?

[Adroight]

It works for me.

[Reely340]

so which mics did you get, and where?
Do you change the whole headset cable, the mic boom or just the tip?
Can you actually change it in the field, twist&lock style?

[Adroight]

I bought a standard Bose A20 headset and two mics - one low impedence and one high. I fly AW and EC machines.

When I want to change the mic I simply unscrew the mic (it is attached to the headset via 2 screws at the boom) and replace it with the other mic. Takes 30 seconds.

I have no idea about Bluetooth as I don't need it.

[Reely340]

So either
A) the A20 comes in a buletooth version OR one with swappable mics
or
B) any A20 accepts the low and high imp. mic, except when using the low imp. mic (military) then the bluetooth feature won't work.

needless to say I'd like Version B)
The question remains where one would find a truly knowledgeable Bose technician, that would be able to tell the truth.

Save choice would be what Adroight is doing, icing on the cake would be B), yielding one single A20 headset that can be adapted to low and high imp. systems with the added joy of blutooth comm in high imp. GA aircraft.

Anyone knowledgeable from Bose reaidng this ?

edit: according to the A20 online manual Page 8,
one can remove the whole cable (including the controller) + mic boom by loosening two screws.

So probably two cables are necessary then:
One High-imp mic w/ bluetooth and a second cable with low impedance mic w/o bluetooth.

[hueyracer]

I´d just jump on to that with my questions...

I fly both-(ex)military and civil helicopters....

I have the Bose Aviation X with (i guess by the shape of it) an electret microfone.

How do i get it to work in both helicopters?
Just changing the mike (as suggested above)?
Where do i get the mike, what´s the part number?

Wouldn´t it (theoretically) be possible to install a "low/high impedance" switch (as one of the DC´s seem to have)....?
As far as i understand, the difference in impedance is a difference in resistance-right?

To answer some of my own questions:

Here is a low impedance cord:
Bose X Military Coiled Cord Cable - 5 ohm mic - U/174U Plug - Marv Golden Pilot Supplies
But this one is for "dynamic" microfones...so where do i get a Bose Aviation X dynamic microfone?

I think the best way would be just to alter my headset to military standard (low impedance cord and dynamic microfone), and then use this adapter:
Low to High Impedance Adapter (Helicopter) - MyPilotStore.com

The other way arouns, the adapter needs a battery (unreliable in my opinion)....
Any comments?

[re-ject]

Bose A20 High Imp Mic

Good day


I am changing office from Airbus to AW, and I need the purchase a Bose A20 High Imp Mic to fit my A20, and was wondering if anyone knows of a place/store in either the UK or New York area?

I have spoken to Bose UK, and they don't sell separate Mic's!

Thanks in advance

Re-ject

[md 600 driver]

All that is available from Bose is the mike kit which includes a new lead and control box

[re-ject]

Cheers, I was not aware I needed the whole kit (i.e. new lead and control box)

[griffothefog]

Originally Posted by re-ject

Cheers, I was not aware I needed the whole kit (i.e. new lead and control box)

I just replaced mine at a cost of €200 😱

[Linda787]

Was told by Bose tech that only the no Bluetooth box is compatible with low impedance mike. If you have a Bluetooth system on your A20, you ll have to change the box (and the mike of course) ! There is also a converter box available at certain pilot shop. It works fine but the battery drain rather fast !