Is there any way to find out if your aircraft is high or low impendence?

I tried a normal A20 for airplane with a plug converter, and the mic did not work. Do I require high or low impendence?

Thanks

Impedance for C++ and 225
 

Hello

Does anybody know if the Bose A20 needs a high impedance lead for:-

- An S76 C++
- An EC225 (I think it uses low on the 225 but am not sure)

If I fly different types which use both high and low impedance respectively, will I be able to get both a high and low impedance lead for one headset, or will it mean having to buy two headsets?

We operate a few types and just want to make sure before I get a headset.

Thanks in advance

Hi
S76 C++: High Impedance
EC225: Low Impedance.
Cheers
FH

There is no need to buy another headset. It is only the microphone that has the impedence issue. Buy two (one high and one low) and then simply plug in the one you need at the time. Much cheaper ;)

Thank you FH and Epiphany. Much appreciated

Best Price for the A20
 

Does anyone know where online you can get the best deal for a Bose A20 Headset?

Either in the USA or UK preferably and from a reputable supplier.

Thanks

Anyone know if

A20® aviation headset with U174 helicopter plug and Bluetooth®

Will work in R44 and AW139 ? The 139 has the drop down leads with the NATO socket on the end of the cable.

I am guessing they are both high impedance, is this right ?

Cheers

A20 and thick templed eyeglasses
 

I have a set of the A20. I am about to get new corrective lenses and frames. The frames I am looking at though have a relatively thick tremple. the Bose site stipulates that thick temples may interfere with the noise cancelling properties of the headset.

Has anyone had any experience with wearing thick templed glasses with the A20?

Yes, it does affect the ANR a lot.

@Elias.K Thick temples affect noise reduction a lot. I went through a lot of sunglasses to find ones which affected it the least.

@SFIM A20 work in R44/22 directly for me, no idea about AW139 or Hi-Z Lo-Z

They work great in the 139. High Impedance...

@EternalRookie .. How did you test it with so many sunnies? did you take the headset to the store?

Just when i thought I found the glasses i like, I'm going to have to find something else. :(

I bought el-cheapos from various 7-11's and ebay till I found a style that did the job and fit my face. That way I was able to give them a decent try out. Then I ordered a decent pair that matched the cheapies.
I ended up settling on these Quantum Promo Store
The temple is thin enough not to break the seal against my head. Springy hinges seem to help too. Lucked out and got them for half price off ebay with the hard case.

Bose A20 ANR squeal
 

Scroll past the rave "review" at the top of
Bose A20 review. Another leap in ANR. | The Joy of Aviation
to the comments section: "Erin" and "Bob" found their A20s to squeal,
and "Fred" shows how to reproduce that:
I did appr. 10h helicopter training using A20s - hence not qualified to judge - but found that only seriously catching the cord somewhere makes the ANR go crazy, read fail.

Anyone else got that "A20 squeal" and grinding his/her teeth for having to live with that? :confused:

Can someone please repeat "Fred's test" with a Zulu2, preferrably side be side with some A20s? :E

I'm a little bit worried, as I was on the brink of shelling out a grand for an A20.. :suspect:

Never had a problem myself. I fly Robinson, Eurocopter and Bell - just back from a flight today and tried the 'Fred test' but couldn't reproduce the 'A20 squeal' either.. :confused:

I've had the squeal the last two times I've flown. The only difference was I changed batteries. I've gone from the Duracell to Energiser Lithium.

Might have to play around with that.

OK - my A20s have duracell back-up batteries, but are powered by the aircraft (if that should make any difference!)

TTB

Not sure if it helps but some lithium batteries last longer but have a slightly lower voltage, this may be the cause of ANR problems.

I have used my A20s for about 30 hours and they are great, but you do have to make sure the seal is good around your ears.

Have had no such problem with Bose of any model including A20, but a similar problem with Zulu. The ANR as I understand it does somewhat depend a suitable seal between the earcup and head to operate properly.

Had mine for two years now and no issue at all other than the cable problem which Bose replaced! Love them!! :ok: