PA install question?

[alex4659]

If this thread is in the wrong spot... please let me know, Thanks

Anyway, I'm going to install a systems 9000 (already have the spectra hooked up) in my intrepid (police package) and was wondering if the wires that are going to the PA speaker are a certain polarity... because the speaker i got from radioshack has the polarity on the wire them selves... (black wire :: black wire with white stripe).

I'm getting it installed early next week and need to know what to do?


thanks,
Alex

[ILMRadioMan]

I am pretty sure you can splice them either way, you should be fine.

[alex4659]

is there a source that you know of that i can use?... maybe a link or something?

thanks,
Alex

[ILMRadioMan]

I would check batlabs.

But I have installed many systems 9000 and they have all been non-polarized.

[alex4659]

thanks for the quick replies but I think i might have a little problem...

I have a motorola A9 spectra (NON-ASTRO) and a motorola (ASTRO) systems 9000 PA amp with DEK box; will these 2 different pieces of equipment work well together or am I going to have to baby-sit... in other words am I going to run into some problems; if so what might I run into?

Also, on the back of the DEK box and the A9 head are a VIP jack, Mic jack, and a i think the main cable jack (ON BOTH) correct me if I'm wrong... anyway there is an extra cable a short one that goes from the mic to the vip jack from either the A9 head to the DEK or vice-versa; what is the proper way to connect this very short cable so that everything works properly?

thanks,
Alex

p.s. -- I'm asking this because i don't want to spend like $100 to find out that my set up is not going to work.

[alex4659]

and one more thing, my speaker has a max of 50 watts will this speaker blow?

I was reading around on bat board - bat labs and read something that said:


by bellersley » Mon Apr 16, 2007 7:18 am

"Well, most sirens are either 58, 100 or 200 Watts, so a..."

let me know if I need to exchange my speaker for a 100 watt because I can if necessary.

[firetaz834]

To play it safe, I would exchange your speaker to a 100 watt speaker.

[alex4659]

ok, ill do that... better safe than sorry right?

but will my astro amp work with my original spectra? not the astro one.

thanks,
Alex

[ILMRadioMan]

I do believe so.

Now this is not something I have tried, but the pinouts on those connectors should be the same (they didnt re-engineer the wheel when they made astro spectra)

The small wire you are are talking about goes into the VIP connector on the back of the control head to control it.

[alex4659]

Originally Posted by ILMRadioMan

I do believe so.

Now this is not something I have tried, but the pinouts on those connectors should be the same (they didnt re-engineer the wheel when they made astro spectra)

The small wire you are are talking about goes into the VIP connector on the back of the control head to control it.

then does the mic hook up be hind the DEK or the control head?

[jparks29]

The speaker you pick up @ rat shack is 8 ohms or 4 ohms. Siren speakers are 11 Ohms.

Mic can be plugged into either DEK or control head. DEK switches audio regardless.

Why do you need PA? Radio rebroadcast I can see, but PA?

[code3cowboy]

Originally Posted by jparks29

Why do you need PA? Radio rebroadcast I can see, but PA?

To talk to people. Radio rebroadcast is not needed because of the advent of portable radios.

"Dont jump its not worth it"

[linkinpark9812]

Ok I have a couple questions as I may get the Siren/PA (Siren disabled of course).

I am cheap and don't have money to just throw around so i don't want to get a FedSig, etc. Siren.

I was looking at the ohm calculations for speakers and how it works and I was wondering. On Batlabs, it says u can set the PA to 65W, 100W, and 135W. This is assuming you have a 11 ohm speaker. Well the RadioShack ones are 8 Ohm. Since that is less resistance, more watts are going to go to the speaker. If my calculations are correct, if you set the PA to 65W, the RadioShack 100W speaker would see just under 90 Watts.

Now if I am right, that would be OK for the speaker. HOWEVER, RadioShack "advertises" 100 W, and they aren't lying, but that is the MAXIMUM output. Its RMS is 50W. Now does this mean if I am pumping 90 W to it occasionally it will be messed up?

If someone on here is good at the ohm/watt calculations, please correct me if this is wrong on hooking a 8 ohm speaker to an amp expecting a 11 ohm speaker.

Also, I have been searching and really couldn't find anything on changing the power of the PA (65W,100W,135W). Is there a switch on the PA somewhere or what?

Thanks!

--linkinpark9812

[linkinpark9812]

Originally Posted by linkinpark9812

Ok I have a couple questions as I may get the Siren/PA (Siren disabled of course).

I am cheap and don't have money to just throw around so i don't want to get a FedSig, etc. Siren.

I was looking at the ohm calculations for speakers and how it works and I was wondering. On Batlabs, it says u can set the PA to 65W, 100W, and 135W. This is assuming you have a 11 ohm speaker. Well the RadioShack ones are 8 Ohm. Since that is less resistance, more watts are going to go to the speaker. If my calculations are correct, if you set the PA to 65W, the RadioShack 100W speaker would see just under 90 Watts.

Now if I am right, that would be OK for the speaker. HOWEVER, RadioShack "advertises" 100 W, and they aren't lying, but that is the MAXIMUM output. Its RMS is 50W. Now does this mean if I am pumping 90 W to it occasionally it will be messed up?

If someone on here is good at the ohm/watt calculations, please correct me if this is wrong on hooking a 8 ohm speaker to an amp expecting a 11 ohm speaker.

Also, I have been searching and really couldn't find anything on changing the power of the PA (65W,100W,135W). Is there a switch on the PA somewhere or what?

Thanks!

--linkinpark9812

bump. Anyone?

[stateboy]

Originally Posted by code3cowboy

Radio rebroadcast is not needed because of the advent of portable radios.

That is the most ignorant statement I've read in a long time. My bum, it isn't needed. I've used radio rebroadcast more times than I can count, and yes I've got a portable radio...a vehicular repeater too. Just because you don't see a need for it, doesn't mean someone else doesn't.

To the OP: You need a speaker rated for 100w at 11 ohms, i.e. nothing you can buy at RadioShack.

[stateboy]

Originally Posted by linkinpark9812

Also, I have been searching and really couldn't find anything on changing the power of the PA (65W,100W,135W). Is there a switch on the PA somewhere or what?

There is a jumper inside the unit to select low (65w) or high (100w) output. If you connect two 100w 11 ohm speakers, the unit will provide the 130w output. Mind you these are for siren tones. When the PA and RRB are selected, the audio output is less...somewhere around 30w IIRC. However, use an 11 ohm speaker.

[linkinpark9812]

Originally Posted by stateboy

There is a jumper inside the unit to select low (65w) or high (100w) output. If you connect two 100w 11 ohm speakers, the unit will provide the 130w output. Mind you these are for siren tones. When the PA and RRB are selected, the audio output is less...somewhere around 30w IIRC. However, use an 11 ohm speaker.

Great! Thanks!

Ya, i have looked at ebay and you can get a used siren speaker pretty cheap. Since I have no need for a siren, I won't be programming it (unless it is to just try it out in the garage). Wouldn't want siren tones programmed and have the cop question about it since I have no reason to have them (two words, stupid and illegal)

All I want it for is Radio Rebroadcast and PA. So 30W is the maximum for the PA and Rebroadcast then? I know it is adjustable like the regular spectra speaker (aka the volume control on the control head), but 30W is the loudest correct?

Thanks again for the response!

[ke7joi]

Originally Posted by alex4659

If this thread is in the wrong spot... please let me know, Thanks

Anyway, I'm going to install a systems 9000 (already have the spectra hooked up) in my intrepid (police package) and was wondering if the wires that are going to the PA speaker are a certain polarity... because the speaker i got from radioshack has the polarity on the wire them selves... (black wire :: black wire with white stripe).

I'm getting it installed early next week and need to know what to do?

Ok I just did what you are trying to do so Iwill try to anwser all the questions once and for all.

#1 as other have have said the speaker does not care about polarity it does care about impedence it must be 11 ohms and the power rating of the speaker must be at least 100 watts or the PA unit will report speaker short.

#2 the dek box plugs into the A9 head at the VIP connector with the short black cable. The mic remains in the mic connector on the A9 head

#3 when the s9000 unit is placed in extrad or pa mode the volume is controlled by the volume rocker on the control head but output power is not limited to 30 watts it is still capable of 100 watts only limited by the volume level set by the operator.

Just for those who have to take a stab at putting other peoples projects down. I also use radio external and PA function all the time to monitor the radio when out of vehicle. As it is not legal to rebroadcast public service traffic over ham channels.

[linkinpark9812]

So Connecting a Federal Signal BP100 would work then correct?

I am pretty sure it is 11 ohms (as it is a siren speaker) and rated at 100 watts.

Their manual say about risk of running with other amp, blah blah blah.

I guess it should still work with the Spectra PA right?

[ke7joi]

Yes that will work just fine