speaker power rating

[markytbass]

How do you find out what power rating of a speaker is? I know it is printed on most units, but what if it isn't?

[Balcro]

[quote name='markytbass' post='326326' date='Nov 10 2008, 09:52 PM']How do you find out what power rating of a speaker is? I know it is printed on most units, but what if it isn't?[/quote]

You could start by posting a couple of pictures. Front, back & sides. If you remove the unit from the cabinet, then you will usually find some sort of serial number or code stamped or cast into the chassis. That info and the pics could be a starter. Then the opinions will come flooding in.

Balcro.

Edited November 10, 2008 by Balcro

[Bill Fitzmaurice]

[quote name='markytbass' post='326326' date='Nov 10 2008, 04:52 PM']but what if it isn't?[/quote]Use it and don't worry about it. You'll hear it farting out from overexcursion long before you approach its limits, if it does, turn it down.

[skankdelvar]

[quote name='Bill Fitzmaurice' post='326413' date='Nov 10 2008, 11:31 PM']Use it and don't worry about it. You'll hear it farting out from overexcursion long before you approach its limits, if it does, turn it down.[/quote]

Er...if there's no info, what if it's 2 or 4 ohms and he's running it off an 8 ohm output? Always thought that was a no-no?

[Bill Fitzmaurice]

[quote name='skankdelvar' post='326451' date='Nov 10 2008, 08:48 PM']Er...if there's no info, what if it's 2 or 4 ohms and he's running it off an 8 ohm output? Always thought that was a no-no? [/quote]
I'm not aware of any 2 ohm cabs, and valve amps aren't bothered by lower loads than the tap rating, only higher loads. But in any event he asked about power, not impedance.

[Musky]

[quote name='Bill Fitzmaurice' post='326457' date='Nov 11 2008, 03:25 AM']I'm not aware of any 2 ohm cabs, and valve amps aren't bothered by lower loads than the tap rating, only higher loads. But in any event he asked about power, not impedance.[/quote]

Are you sure about that Bill? I'm a very long way from being any kind of expert, but I thought it was commonly held to be the other way round.

[Merton]

The easy way I remember it is that valve power stages don't mind short circuits, solid state power stages don't like them.

Solid state power stages can do open circuit, but valves can't.

The lower the impedance, the closer to short circuit, so Bill is right.

[Stewart]

Valve amps don't like higher impedance loads (say 16 ohm, when the output transformer only has taps for 4 and 8)

Transistor amps don't like loads lower than they're rated for (and if they don't have good protection, it can be terminal quite quickly)

(edit - Merton too quick for me !)

Edited November 11, 2008 by Stewart

[Musky]

I'm totally confused now, but with the overwhelming weight of opinion here I'll take everyone at your word.

I'm not going to be using my VA350 with any cabs that don't match the tap anyway.

[markytbass]

The speakers are Fane and label on the magnet says "extra high power, super efficient" they are 8ohms and have the numbers 42/79 & 15381 printed on the chassis of the speaker. I have e-mailed Fane with all the above info and am waiting to hear back.