B

Bob Hoffman

Well Known Member
I have an ANR headset that have the ANR portion powered by a 9v battery pack,the cord has a little plug that plugs into the battery case.

Now,bearing in mind that I'm not an electrican,what do I need to do to convert the aircraft 12v power to a 9v plug so I can eliminate the battery pack.

I was thinking of putting a receptacle next to the head set jacks.

I have a "tilt" so I'm putting the jacks in the rollbar support where the rear window is.

A suggested sorce for the required parts would also be appreciated.

Thanks
Bob
 
Bob,
Go down to the aviation section of your nearest Radio Shack and get a 9v converter. Hard wire this in and put a jack next to your headset jacks. I tied mine in to the avionics master so it turns off the headsets when I turn off the AV master.
 
Last edited:
Another way would be to...

call up your headset manufacturer and get a lemo conversion kit. About $150 for the Bose.

Hans
 
LM7809

A 9V linear regulator would be a very simple solution. The LM7809 is a 3-pin device that will take anywhere from about 11V to 35V input and give you a clean 9V output up to about 1A in a TO-220 package. The LM7809 has been around since the dinosaurs walked the earth, it is made by multiple manufacturers, should cost less than a buck, is available from online distributors such as Digikey, and probably even at Radio Shack (Mel, is that what you used?).
 
Yep, the 7809 works fine (7810 is actually better as a 9.6v supply) and with two additional caps (0.1 and 1uf), you've got a $3 solution. Solder the caps together directly on the regulator with pigtail leads and shrink wrap the whole thing.

And at the low power levels needed, the linear regulator is quiet and works very well.

I have built many of these for friends and their ANR headsets as a ships power unit. Order the right mini jack for the deal and install in less than one hour.

If anyone wants to not deal with the solder, I'll send you one built for $20 ($30 with the jack which you need to specify for your headset).
 
Thank you all for your responses.
Deene -- what are caps (0.1 & 1uf) ??? what do they do ?
Thanks again
Bob
P.S. Is a 9V battery 9V or 9.6V ? (do I need the LM7809 or the LM7810)?
 
Bob Hoffman said:
Deene -- what are caps (0.1 & 1uf) ??? what do they do ?
Click to expand...

Capacitors. Adding input and output capacitors as Deene suggests helps clean up the signal even further, and in some cases is necessary for stability of the regulator. In this application you could probably do ok without them, but adding them is certainly a good idea.

See Figure 7 in the LM7809 datasheet: http://www.fairchildsemi.com/ds/LM/LM7809.pdf

Bob, if you're not electronically inclined, consider taking Deene up on his offer to sell you a complete circuit.

Bob Hoffman said:
P.S. Is a 9V battery 9V or 9.6V ? (do I need the LM7809 or the LM7810)?
Click to expand...

What type of battery is it exactly? An alkaline 9V battery really is nominally approximately 9V (six cells, ~1.5V per cell). A rechargeable battery pack composed of eight NiCd or NiMH cells (~1.2V each) would be more like 9.6V nominally. In either case, there will be quite a bit of variation in battery voltage depending on load and decreasing as the battery discharges. Battery powered devices are therefore generally designed to accommodate a wide variation in input voltage. What really matters is what is the input voltage range that your headset requires? Anywhere within that range should be fine.
 
Last edited:
ken9

I am wiring this elcheapo 9v power supply for my Headsets Inc. ANR. Can anyone tell me where to get the correct mini jacks for the system?
 
The aviation aisle at Radio Shack. Assuming that it's a standard 1/8" jack.
 
Ken9 said:
I am wiring this elcheapo 9v power supply for my Headsets Inc. ANR. Can anyone tell me where to get the correct mini jacks for the system?
Click to expand...

For the 9v power plug... It has a locking thumbscrew on it, so it's nice to have a jack with a long threaded bushing with enough threads exposed past the mounting nut so you can lock the plug in. I went with these from Mouser: http://www.mouser.com/Search/ProductDetail.aspx?R=L722Avirtualkey50210000virtualkey502-L722A

If you don't care about locking the 9v plug to the jack (and it's not really a safety issue, you'll just lose the ANR feature if it disconnects), any usual 2.1mm pin DC jack will work, I think.

--Paul
 
Mel said:
The aviation aisle at Radio Shack. Assuming that it's a standard 1/8" jack.
Click to expand...

I assume you are looking for the power jacks. You need 2.1 mm barrel power jacks.

Search digikey.com and you'll have several choices. It's really hard to find the screw-down types, but there is a school of thought that says you don't want your headset affixed to any structure in the aircraft in case you have to exit quickly.

Vern
 
Check Your Jack Location

Bob:
One of the things I wish I'd done different on my 9A is put the jacks forward of the seats for better access. I thought I was getting the wires out of the way, but the trade-off hasn't been worth it. Realized the problem the first time I tried to get at them in flight - not impossible, but not good, either. Your decision.
Terry, CFI
RV-9A N323TP
 
ken9

Thanks for the help guys. The mouser barrel looks like the closest to those on my ANR box. Will also consider the issue of being "screwed" to the airframe in case of a quick exit.
I did locate my jacks behind the seats but on the outside walls (eg. left side of pilot and right of passenger) but have not flown it yet so we'll see if it is an issue. It seems to keep the cords out of the way of controls.
 
Switchcraft makes a long bushing jack for the locking jack. Look at Digikey p/n's SC1150 or SC1151 depending on the center contact size.

I used one of these for my Headsets, Inc ANR plug (but can't remember which size).
 
ken9

deene, Can you refer me to a circuit diagram for the LM7809 with caps you suggest? I would like to build this but do not know exactly where to put the caps.
 
ken9

Hey thanks. Looks pretty simple. Just wire .33uf cap between 1 and 3 and .1uf between 2 and 3. I assume the caps keep the output voltage more constant as the electrical system voltage varies.
I think I will mount it on a small piece of aluminum for heat sink and mechanical support.
 
Yes, caps improve stability and regulation.

You can mount on aluminum or just solder caps on the regulator leads directly along with the wire leads to connect to your system. Then put it in a piece of larger heat shrink and tie it to the wire bundle. Unless you are using a lot of power the heat sink is not needed.
 
You must log in or register to reply here.