CJ 24 Speaker 12v or 110?

[Skulldigger]

I found this speaker today and it has no makings on it. I"m pretty sure it's a CJ24.

My question is did they not make these as PA speakers as well being 110v instead of 12? How would I tell the difference with no markings. The price is good, but I don't want a PA speaker I can't use.

 

[kitn1mcc]

the speaker would need a siren amp to drive it

 

[Stampeed Valkyrie]

PA speaker or not... none of them ever ran @ 110V. The amplifier might have been 110/120V but the speakers are low voltage coming from the amp probably 24V if its a PA speaker. I'd be more concerned with if the driver was blown or not.. 9V battery trick, or hook it up to a 12V Siren/PA unit.

 

[dmathieu]

I don't think it's the Voltage.

 

[Skulldigger]

PA speaker or not... none of them ever ran @ 110V. The amplifier might have been 110/120V but the speakers are low voltage coming from the amp probably 24V if its a PA speaker. I'd be more concerned with if the driver was blown or not.. 9V battery trick, or hook it up to a 12V Siren/PA unit.

I don't think it's the Voltage.

So this is likely a vehicle speaker then right? CJ24?

 

[dmathieu]

I believe you need to know Watts and Ohms.

 

[Stampeed Valkyrie]

Without going too much into it... most speakers are 8,4,2 ohms in rating.. and the wattage doubles every step down..
so 50w @ 8ohms, is 100w @ 4ohms, and 200w @ 2 ohms.. (my math might be wrong on the 2 ohm part.)

Most automotive speakers are 4 ohms.. and I believe PA speakers are 4 ohms usually as well.. but I have seen 2 ohm PA speakers..

 

[cmb56]

It seems to have the normal Atlas SD-70 driver.
Remove the cover and read the tag that normally is on the Atlas drivers and see what it says.
A Atlas SD-70 driver is rated 58 Watt, 11 Ohm.
https://www.atlasied.com/f/932/SL7.1546.PDF.pdf

Michael

 

[dmathieu]

Typical siren speakers were 58, 75, and 100 Watt, and 11 Ohms.

 

[cmb56]

Typical siren speakers were 58, 75, and 100 Watt, and 11 Ohms.

Can you give me an example of a 75 Watt speaker because I have never seen one.
I know Federal stated 75 Watt on some if the early PA-20 sirens but they used speakers with the Atlas Sound SD-70 driver that is rated 58 Watt.

I am not shure of the rating on the Electrovoice speaker, that is very rare.
Maybe it was 75 Watt.

Michael

 

[dmathieu]

Yeah Michael, I remember some 1960s chrome Atlas speakers that were 75. I'm thinking Signal Stat, maybe others.

 

[cmb56]

I have several of these Atlas Sound speakers and they are using the SD-70 driver but they are from the 70s.

Michael

 

[dmathieu]

LOL, maybe I'm thinking too old, LOL.

 

[cmb56]

I made a calculation regarding Ohms law and 58 Watt/11 Ohm is 25,259 Volt/2,296 Ampere at full power.
Remember that current to a speaker is AC and not DC.
Direct current to a speaker coil will destroy it when to much power will go through the coil.
75 Watt/11 Ohm is 28,723 Volt/2,611 Ampere if there is such speaker or siren amplifier.

Michael

 

[MtnMan]

I made a calculation regarding Ohms law and 58 Watt/11 Ohm is 25,259 Volt/2,296 Ampere at full power.

Uhhh... no. Watts = Volts squared / Ohms.
58 W into 11 Ohms is 25.2 V.

 

[cmb56]

25,2 Volt or 25,259 Volt?
Almost the same depending of if you rounding upp or down.
I use the Cressall calculator and it gave me these values.

Michael

 

[Stampeed Valkyrie]

lol I almost just fell out of my chair reading
I made a calculation regarding Ohms law and 58 Watt/11 Ohm is 25,259 Volt/2,296 Ampere at full power.
not low voltage at all.. but then I am assuming you mean 25.259/2.296 I am seeing a comma and not a decimal point.

 

[MtnMan]

25,2 Volt or 25,259 Volt?

OK, we have an international discrepancy over decimal and thousands separators. In the British and US convention, "25,259" reads as "twenty five thousand, two hundred fifty nine."

The answer I think we both agree on is "about 25 and 1/4 volts."

 

[cmb56]

I wrote it as what is common here in Sweden. I assume that common logic give you the information you need.

Regarding the decimals in what I wrote, it came from the Cressall calculator.
Cressall is a very large manufacturer of resistors and I assume that they know of what they are doing.

Michael

 

[MtnMan]

Whatever. I do this stuff in real life on a daily basis, so I'm quite sure I know what I'm talking about. Peace out, folks.

 

[Wailer]

I know Federal stated 75 Watt on some if the early PA-20 sirens but they used speakers with the Atlas Sound SD-70 driver that is rated 58 Watt.

The actual power output of the PA15 and PA20 (both with wail, yelp, and alert tones) is more like 45 watts.