M1225 External Speaker with Headset Hookup ::Help::

[jc29ems]

Hello All,
We recently installed a M1225 in our engine and need to install an external speaker because the thing just isn't loud enough. We previously had a MaxTrac in place with our headset system hooked up but ended up blowing out the sound card from what we were told there just wasn't enough of output to run it.

Can someone give me instructions on hooking up an external speaker to a M1225 and also let me know if it is possible to hook up the headset system as well without causing any damage.

Thanks,
JC

[witthoft]

Look here : http://www.batlabs.com/m1225.html

[jackhackett]

What type of headset system is it? A decent system shouldn't put very much load on a radio, it would have it's own amplifier to drive the headsets. I can't see a properly connected headset system blowing out a Maxtrac's audio amp.

With the M1225 you have to be sure not to ground either speaker lead. An external speaker should be connected between the two speaker leads, and any connection to something like a headset system needs to be isolated, usually with a transformer (a decent system would have the transformer built in).

[RFguy]

Need more detail on heaset models, interface ype, connection points.

I suspect that one side of the M1225 speaker was gronded and it took out the M1225 audio output (radios and headset don't have sound cards).

[jackhackett]

He said the one that blew was a Maxtrac, which usually have a single ended output so one side of the speaker actually is grounded.. I've seen a couple of radios blown up when someone replaced a Maxtrac with a Radius, they just plugged the old accessory connector in, and the connector had a ground on the (-) speaker lead. You have to watch out for that.

[jc29ems]

We never actually hooked up the headsets again after we changed out the MaxTrac to the M1225. Were afraid it might happen again and blow up another radio.

Here is the specs on the headsets:
Make: Setcom
Model: IM-900
Serial: 3379

Let me know how I need to go about hooking it back up to make sure it won't cause any damage. Also let me know if it would be a problem to hook up the external speaker in the cab of the truck. The headsets are located in the back crew area.

Thanks Again,
JC