XPR4550 questions.

[N4KVE]

Hello. I have the TRBO bug, & have a few questions. I recently got a 6550 to use on a local system, & love it. I am considering getting a UHF "Q" split mobile radio, but need to ask a few questions. I don't want to use an ignition sense wire, just battery hot. To do this, are there jumpers on the acc plug, or just a CPS choice. Also to choose between the internal speaker, or external, again a jumper in the plug, or a CPS choice? On a GTX mobile, jumpers on the acc plug would take care of both of these. Thanks. GARY N4KVE

[Dorf411]

Assy power is not required and the radio will operate just fine using the power button on the front without that wire attached. The internal speaker is always enabled and I don't recall seeing an option in the cps to turn it off. You don't need the assy plug to be installed for the internal speaker to work like some legacy radios do. If you want an external speaker hook one up.

[com501]

If you REALLY don't want the front speaker, disasseble the control head and unplug it when using the external speaker.

[N4KVE]

So I got the radio today, connected an external speaker, & it sounds great, but very quietly in the background, the internal speaker is working too. I don't want to take apart a brand new radio to disconnect the internal speaker, & I can barely hear the internal speaker. So my question is am I going to harm anything? I don't mind running the radio with both speakers, as the external speaker is much louder than the internal speaker, so as long as the radio is happy with both speakers on together, I don't mind. The external speaker is 8 ohms. GARY N4KVE

[com501]

I've been running the four in my truck that way since they came out, sometimes at very loud audio when I am near the tracks servicing a rail inspection car, never had an issue.

[RFguy]

So my question is am I going to harm anything? I don't mind running the radio with both speakers, as the external speaker is much louder than the internal speaker, so as long as the radio is happy with both speakers on together, I don't mind.

This is how the radio is designed to work, so the answer is no, you won't harm the radio. The radio is rated for either an external 8-ohm speaker (will produce 7.5 watts of audio) or a 4-ohm speaker (will produce 13 watts of audio). Motorola does not make provision for disconnection of the internal speaker, so it's normal to have both speakers active.

Most people "assume" that the internal speaker is automatically disconnected when the external speaker is connected. The reality is that the internal speaker is a higher impedance speaker, so with an external speaker connected the majority of the audio power comes from the external speaker and it just sounds like the external speaker is the only one operating.

[N4KVE]

Thanks for the help. Years ago I had a Maxtrac, & I tried running it on both speakers, & it sounded like crap, so I disconnected the internal speaker. I realize the XPR isn't a Maxtrac, but I thought maybe it was the same deal. Thanks again. GARY N4KVE