Peavey Black Widow Speaker Impedance

[TomCarlos]

Friends...

I pulled a Peavey 15" Black Widow from a KB300 keyboard amp. The owner's manual states the amp is 4 ohm. There is a sticker on the side of the speaker that shows 1505 DT - 4 ohms. HOWEVER, the back side of the paper is stamped 10018 and the speaker measures 5.4 ohms DC resistance.

Do you think someone did a recone job on this speaker? I thought it would be typical to measure between 3.2 to 3.8 ohms DC on a 4 ohm speaker?

Tom

[Leo_Gnardo]

Peavey sold replacement baskets for BW's to enable easy field fixes, pre-loaded with cone and voice coil. All it took to repair one was undo the 3 bolts, remove magnet, clear voice coil gap, carefully place a new basket/cone on the magnet then tighten the 3 bolts. Cake! Someone may have not been able to get a 4 ohm basket/cone, but could get an 8 so they went with it. And the show went on, on time.

As you observe, the DC resistance of a voice coil is typically less than the rated impedance of a speaker. I haven't measured too many Peaveys but a similar speaker, EV, typically measures 5.6 ohms for an 8 ohm speaker. Expect 3 or a little less for 4 ohm speaker. We could look up the specs & see what they say, but that's my seat of the pants explanation.

At 8 ohms the amp will deliver a tad bit less power to the speaker, but if it sounds loud enough, it's good enough, no worries.

[TomCarlos]

Thanks Leo....

I too am thinking someone replaced the basket somewhere along the line and this is now an 8 ohm speaker. No biggie... I have a good use for it and yes it sounds fine.

Tom

[tedmich]

On older BWs removing the foam plug inside (if present) before it turns into greasy dust is a good idea.

[Enzo]

The factory sticker is on the basket, not the magnet, so if someone substituted the wrong basket, they would have had to pull the sticker off the old one and stuck it on the new. Seems unlikely. I'd suspect it is still a 4 ohm, but even if it is an 8 ohm, you only lose 3db at most. And the amp works half as hard.

[g1]

Sticker on the side of basket or magnet?

[tedmich]

Does PV sell the 4 ohm or 8 ohm magnets?

[52 Bill]

Does PV sell the 4 ohm or 8 ohm magnets?

I don't know about the magnets, but the listing on the website sez:
Model 1505 4DT dc resistance 3.2 ohms
Model 1505 8DT dc resistance 5.2 ohms.

[TomCarlos]

Sticker on the side of basket or magnet?

The white sticker was on the basket.... That is why I was confused. Peavey recone is the entire basket. So the best i can think of is what Enzo mentioned... Someone might have used the wrong paper cone assembly when dropping it into the basket or they grabbed the wrong sticker.

[Tom Phillips]

Did you check your meter? What resistance reading does it show if you short the test probes together? If it doesn't show 0.0 Ohms then you need to do the math to calculate the actual voice coil resistance.

[TomCarlos]

Yes.... I checked the (digital) meter. It is .2 ohms shorted.