Clear com cc26 compatable with tech protalk back plus home made cans

[stringman]

Hi Guys,

 

top forum.

 

After trying to find a cheap right eard head set and following various links and info from this forum I found myself a used clear com cc26 headset from the states.

It was $100 inc shipping which I thought to be a bargain.

 

Just wanted to confirm that this should be compatable with the tech pro talkback system (4 pin XLR)

 

all help appreciated.

also as an aside I wondered about making my own headset using the following bits

 

panasonic rp hc70 noise cancelling headphones and the microphone (its a clip on mic) from this unit

 

http://cpc.farnell.com/CS10243/computer-pr...equestid=155248

 

is there any way this would work ( I would make a 4 pin XLR to 2 mini jack cable adaptor)

 

I am not optomistic!

 

if not any ideas where I could get a suitable mic to go with these ear phones

 

many many thanks in advance

 

Andy

[mackerr]

Yes, the CC headset will be fine with the Tech Pro system. AFAIK all the major comm systems wire the headset connector pin 1 mic shield, pin 2 mic hot, pin 3 ear low, pin 4 ear high. With a 2ch 6 pin headset connector pin 5 is R ear low, pin 6 is R ear high. With a 5 pin RTS headset pin 3 is ear common, 4 is L ear hot, pin 5 is R ear hot.

 

Mac

[stringman]

thanks for that

 

I thought £50 was a bit of a bargain!

 

any thoughts on my home made idea?

 

cheers

[weatherhead]

I don't see any reason why it shouldn't work in principle... the only thing is sometimes the impedance of these kind of mics and headphones is different than the pro type ones I think, which might mean you end up with massive level discrepancies and/or terrible quality

[stringman]

hhmmm just what I was afraid of

 

if its just impedance could I not just "throw a resistor or two in line " to cure that?

 

I think I will have to suck it an see. if it all goes horribly wrong it will be either

 

a) a tax write off

or

b) a listing on ebay!!

 

cheers

[peternewman]

The computer mic probably wants a bias voltage to make it work too, certainly the socket provides it and I believe a lot of them use it, so you would have to work out how to implement this too (perhaps a lead to borrow power from the Techpro or similar ring?

[stringman]

Peter,

When you say a lead from the techpro ring what exactly do you mean?

 

I was intending to make a 4pin XLR to 2 x mini jack lead so that I could connect into the belt pack.

 

would this be sufficient or would I need to make an additional lead to connect to the system- if so where?

 

I am starting to think "a little knowledge......." may be applying to me here!!

 

thanks

[peternewman]

Its not a particular area of expertise of mine, just something I've read about before. There is a bit more information about mic powering here and as mentioned above you may have impedance issues to deal with. When I mentioned the Techpro ring and additional cables I should perhaps have been clearer, but essentially if you find you do need to supply a bias voltage to the microphone, you could use the 24V DC present on the Techpro ring to supply the bias voltage, stepping it down as necessary, for which you would need to make some kind of lead to "tee" the power off, while still passing power and audio through to the beltpack.

[FullRange]

The mic you are going to use has an impedance of 2.2k ohms, whilst the Tecpro system wants to see around 200ohms (as from a dynamic mic).

I once tried to solve this mismatch using resistors etc, I never got it to work even vaguely well.

Tapping a bias voltage off the main comms line could produce quite a mess of cabling. I don't know what would happen if the wiring failed and there was a short on the comms power line. Would that bring down the whole system?

Instead of tapping off power you could build a battery box to supply the voltage or use a mic that has a built in battery (CPC stock a Sony tie mic that has this). You could also try looking out for an old dynamic clip mic.

[boatman]

These headsets from CPC have a 200 ohm dynamic noise cancelling mic which can be rotated. The headphone impedance (64 ohms) is lower than the recommended 100R for Tecpro beltpacks, but they work fine. They are mono headphones and it's easy enough to remove the unwanted earmuff. I've been using mine since January with no problems.

[stringman]

These headsets from CPC have a 200 ohm dynamic noise cancelling mic which can be rotated. The headphone impedance (64 ohms) is lower than the recommended 100R for Tecpro beltpacks, but they work fine. They are mono headphones and it's easy enough to remove the unwanted earmuff. I've been using mine since January with no problems.

 

 

Now that is interesting.

If I could somehow get the microphone off those cans and somehow connect them to my noise cancelleing earphones I could be in busines.

The headphone impedance of the my headphones is 30 ohn is that too low?

if so is there anything that can be done?

 

thanks