New life for an old speaker?

[David]

I cadged an old speaker in a cheesy plywood cabinet from my church.  It looks like one of those PA speakers that might be found in an elementary classroom.  It's got a 10W speaker with a transformer and a volume control.  I'd like to use the speaker (and transformer if needed) in a low-power amp project.

Does anybody know:

If I could use the speaker alone with a LM386 or TDA2030 type of amplifier?

Or, failing that...

How to connect the transformer to the amplifier and speaker (of course there's no schematic)?

Thanks!

[Arn C.]

David,
The speakers you are talking about are most likely, like the ones I take care of at my job.  The transformers take 70v or 25v?, not sure about the 25v, something like that, anyhow, the transformer has one of those inputs and the other side is knocked down to 8 ohms.  Mine have several taps, for different wattages.  

I take the transformers off and I have a 10 watt 8 ohm speaker to use!
Some of the speakers are cheap and some are real nice!
You can always ohm the speaker connections to see what ohm value it is.  Generally they are 8 ohms.

Peace!
Arn C.

[petemoore]

I don't know exactly what the transformer is for
 Could be for a passive Xover, or some kind of voicing notcher[just guessing. someting to alter the ohmage...
 I would try connecto to ampo just to see what comes out...probly won't burn the amp doing that, but I keep dirt $ amps around for just such occasions.  Like an old computer speaker amp or whatever console stereo/ 386 thing I have there. A cheep test amp...yes.
 Just start with the volume low and work up.
 Might want to throw the ohmmeter on it to see what it reads.
 Some of those type speakers have very high ohmage.

[Mark Hammer]

I've bought a number of these PA speakers and they do a great job for small practice-type amps.  The speakers generally have a fairly wide frequency response and are efficient enough to produce decent volume from even a modest power amp.  

The transformer is there for the purposes of stringing several dozen units together for a school or business-wide announcement system.  Obviously, it also serves the function of isolating speakers from each other.  Or more importantly, isolating those wirewound fader controls in each cabinet from each other.  

When used as individual speakers, the transformer is superfluous.  The fader pot *could* serve as a kind of amp attenuator "power brake" thing, but you'd need to be careful with respect to the power you feed it.  Normally these things are only rated for maybe 2-5W before heat gets the better of them.

A decent cabinet can make them sound terrific.  There is one of these speakers in a Gorilla amp I picked uplast weekend and I'm impressed with how well this thing works as a low power (15W or less) bass amp.