Turtlerock Forum

Years ago someone informed me I could use a AA battery to test the positive or negative of a speaker by the speaker moving forward off the positive end of the battery.
About 6 months ago I tried it on a Rola 12UX and found the positive (speaker moved forward), I double checked it by reversing it, and then went back to the Positive terminal and....nothing... speaker no move no more.
This may just be a coincidence, the speaker may have been on the way out.
Is this safe for an old speaker - can it be damaged by doing this?
I have another nice old Rola in a old film projector box that I want to add a 1/4 inch plug for use with my old amps.
If I am doing something wrong here I don't want to do it twice - These are some of the nicest guitar amp speakers I've ever heard.

You're applying 1.5 volts to the speaker, so assuming an 8 ohm coil, then (P = E squared/ R) the power is 1.5 x 1.5 / 8 = 0.28 watts. So, assuming the speaker is intended to handle that amount of power, it should be no problem, UNLESS, you leave it connected, since the speaker is expecting a complex AC wave form, it is not advisable to leave a DC source connected for an extended perion.

That said, I have checked any number of speakers with a 9V battery without any issues. I'd suggest the Rola was faulty before you tested it.

Thanks Bob,
send the Rola to the doctor

Like Bob, I've checked polarity of quite a lot of speakers that way over the years, without the slightest problem. I keep a few spent 9v dry cells around (they trickle a volt or two) that I use for this kind of thing.