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Need help - What's the ohm & power rating on my cab?


amcka

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:confused: Anybody mind giving me a little help?

 

I have a Peavy cab that I think is probably from the 80s maybe early 90s - picture on the left. It's got 2 15's. I looked inside last night and also noticed the speakers have square magnets - but nothing printed on them as far as ratings. Anyways - just trying to figure out how many ohms and watts it's rated at. Anyone know off hand, or could direct me to a site that would have info?

 

Any help much appreciated!! :)

"...I'm working fast food now... but, hey, at least it's better than my last job."
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Can't help you on the power rating, but by using an ohm meter and a little logic you can determine the impedance of the cab. Since 4 and 8 ohms are by far the most common impedances for bass cabs it will be easy to identify which you have.

 

An ohm meter can't read impedance directly, but it can read static resistance. Plug one end of a speaker cord into the speaker jack and measure the resistance at the free plug. You will be also measuring the resistance of the cord, but that's negligible for our purposes here. An 8ohm cab will read less than 8ohms, but greater than 6ohms on the meter. A 4ohm cab will read less than 4ohms, but more than 2ohms.

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Yeah, what Mudbass said is essentially it. An 8-ohm load will typically read above 6 or so, and a 4-ohm load maybe as low as 3.2.

 

But. With older cabs its always wise to measure each speaker separately using that method. Because some peeps will just nilly-willy put any old drivers they can get their hands on into a cab - cosmetic match or not (and then wonder why they keep blowing their head up). That's one thing I've seen countless (or at least 10) times in old cabs.

 

So, just to be safe, disconnect the speaker wires from the terminals on the speakers (note orientation of + and -) and place the meter leads on each speakers' terminals to get your measurements.

 

Then (and this is the tricky part) connect the speaker wires again before closing everything back up. That saves some frustration ; }

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Judging by the dustcaps over the voice coils, what's in there could be rated at 200-300 watts RMS. But there is no sure way to tell except a part # for each speaker. Actually what is in there could be ANYTHING - guitar, PA (which is usually close for bass), etc.

 

It seems to me Eminence used square magnetic assemblies in the dim dark past, on many of their guitar and bass speakers. So, could be anything.

 

Parts # are sometimes stamped into the metal somewhere, or on a small paper label on the side of the manet assembly, or stamped in white paint on the cones, or... To find ones not easily seen, take the speakers out, and sometimes you will see one of those things somewhere.

 

Than, it's internet and/or phone time. Or you could just make sure you aren't breaking any ohms rules, and use them until they give out, or you can't stand the sound of the farting any more ; }

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haha 37 - dudes - thank you for the info. Arright... I'll try the ohm meter as soon as I can pick one up somewhere.

 

BTW - it actually doesn't sound too bad. I have been using it a lot lately. Big fat bastard to haul around tho :)

 

At some point I think I will replace the speakers in it... yes maybe when the farting finally drives me batty.

 

again - thanks everyone - have a good day!

"...I'm working fast food now... but, hey, at least it's better than my last job."
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