Estimating speaker power rating

[TheLustyGhost]

Hi!

I've got a 12" EV speaker that has nothing printed on it - no model number, serial number or anything.  It has a pretty hefty magnet on it, so I imagine it is probably designed for at least 100 watts, but I'm not totally sure.  Any suggestions for making a good guess?

[EdBass]

Are you sure it's an EV? Post some pics, I'll bet somebody can ID it.

[basiklybass]

It is fairly easy to make a speaker look big and beefy.

Some of the older EV SRO's were rated at well over 100 watts

I wouldn't make any judgment on a speakers capacity based on how it looks.

Like Ed said: got any pictures?

[TheLustyGhost]

I can put one up soon.

The EV logo is stenciled on the dome, so I am sure it's an EV.  Everything that was stamped on the chassis is missing.  I can post some pictures this afternoon.

Interesting thing is, it has spring-loaded binding posts rather than solder pads.

[basiklybass]

http://cgi.ebay.com/EV-SRO-12-WHITE-COFFEE-CAN-TYPE-NO-RESERVE_W0QQitemZ190106815583QQihZ009QQcategoryZ121165QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
This is a link to EV SRO's being sold on Ebay. They also have binding posts.

Look anything like it?

[TheLustyGhost]

Not really:



It looks like the stock EV speaker in this Acoustic g100T amp:

http://acoustic-amps-usa.privat.t-online.de/14543/14651.html


Which would make it an EVM-12L:

http://acoustic360.homeunix.net/products/main/g100t-112.html

If it is an evm-12l then it is either 200 or 300 watts depending on when it was made.  Think that my '68 Solarus would be able to drive it plus a 50 watt Eminence Cannabis Rex?  I've got a 100 watt Carvin BR-12 in there with the C.R. right now and it's doing fine, but somehow I doubt that a speaker that's rated at 300 watts and is getting hit with 25 watts is going to sound that great.

What do you think?

[TheLustyGhost]

Also, I just tried to do a crude impedence measurement, by measuring the DC resistance from one binding post to the other (9.5 ohms) and multiplying by 1.3, which gave me 12.35 ohms.  Pretty much dead center between 8 and 16.  Any suggestions for figuring out the impedence?  I have a signal generator and multimeter, but that's it for test equipment.

[EdBass]

I'd say it's an EV. It's hard to tell which model with EV's though, they largely share frames and motors, the difference is in the cone assembly.
It's probably a 16 ohm EVM or SRO. EV's are great drivers, even with the big power rating, they are very efficient. I'll bet your Solarus will drive it fine.
As far as pairing it with a Cannabis Rex...
As far as I'm concerned, anything goes with guitar cabinets. Make sure your speaker impedance situation is copasetic with your output tranny and let it rip! You might hate it, or you may discover the new "Holy Grail" of guitar cabinets.

[TheLustyGhost]

It's definitely an EV, like I said the EV logo is stenciled on the dome.

If it's 16 ohms I can't use it in the combo, but I COULD use it in a 1x12 extension cab.  I've actually seen a couple of posts about matching an 80s EVM12l with a Cannabis Rex - the guy REALLY liked the combination.  I'm guessing it's an EVM simply because it was mounted in a guitar cabinet (the SRO line wass marketed more as a PA speaker, wasn't it?).  Thing is, the speaker that I swapped for it was 8 ohms and the cab it's in (with another EV), and it didn't give him any trouble (in fact, it actually improved the tone he was getting, suprisingly).  If the impedence of the speakers was mismatched, I'd imagine things wouldn't sound quite right even if the amp wasn't damaged.

[EdBass]

It's definitely an EV, like I said the EV logo is stenciled on the dome.

Well, it's definitely an EV dust cover anyway. Your speaker had a big, very cool looking finned aluminun magnet cover on it originally, that's what those theaded holes around the edge of the magnet are for.

The speakers don't care about an impedance mismatch, but be aware that the lower impedance speaker will get more juice than the higher impedance one will. Your output transformer will definitely care about the total load.

[JoeArthur]

http://acoustic360.homeunix.net/products/main/g100t-112.html

If it is an evm-12l then it is either 200 or 300 watts depending on when it was made.  Think that my '68 Solarus would be able to drive it plus a 50 watt Eminence Cannabis Rex?  I've got a 100 watt Carvin BR-12 in there with the C.R. right now and it's doing fine, but somehow I doubt that a speaker that's rated at 300 watts and is getting hit with 25 watts is going to sound that great.

What do you think?

Ha!! That's my amp. Here is a closer view of the speaker - 8 ohms, 200 watt.



It is very efficient and great sounding.

[TheLustyGhost]

Your output transformer will definitely care about the total load.

Yeah, that's what I'm worrying about.

Either way, I'm happy enough with my sound now that I might make an oversized 1x12 cab and use it for bass; I just need to figure out whether I have to rewire my 8 ohm 4x10 for 16 ohms or not. 

[TheLustyGhost]

Looking closer, there's a very faint "209" stamped on the back of the magnet

The cone is stamped

Y91 95
Then under that, but upside down, what looks like
4 40
but the zero looks more like an omega turned sideways.

[mckinnon audio]

 Hi there, what you have there is a EVM-12L or B ( can't tell from the back ) made for manufacturers of amps, pa's etc. It has 3 tapped holes in the magnet for the black finned heatsink that would bolt onto it and there would be a EV sticker/decal also, but only if you were to buy it as a raw driver, or in a piece of EV gear. Other than that it's the same as a regular 12-L, might run a little hotter than one with a heatsink if you power it up to max. Good luck Mel.