can you have the ohm rating changed on a speaker?

[vanguard]

if i want to switch a 15 ohm speaker to 8 ohms, is that possible? it would have to be reconed anyway, so i was wondering if i could have this done at the same time?

thanks

[Tonemonkey]

Never heard of changing a speaker's ohms.
Get a new speaker - or an old one; just get one of the right resistance/impedance (or what ever the ohm geeks want to call it) for your OT!

[Tim Armstrong]

Yeah, you're basically just using the basket and maybe the magnet, and building a whole new speaker around it. Probably cheaper and definitely easier to just buy a different speaker!

Tim

[Wally]

Using a large enough resistor...wattage rating....you can wirein series or parallel with the speaker and attain a differeng impedance. I wondered about this after having a certain 8" speaker reconed and then realizing that it would fit perfectly...and might have come from a Gibson amp....but that it needed to be 8 ohms to work in my GA-30. I talked to TEd WEber, and he said that the above remedy would work....and so it did....and still does. I do wish that I had had the speaker reconed at 8 ohms, but I did it before I got the amp. For an 8" speaker, it has a huge magnet. The size of the magnet makes it proper for this amp. I have compared it to another GA-30. Someday I might have the speaker reconed at 8 ohms. Until then, it is working fine and yields the correct impedance when paired with the other speaker in the amp...a 12", 8 ohm.

[Giant]

i dont think you can use resistors to REDUCE resistance. hes talkin about going from 15 down to 8. resistors add resistance, so to go from 8 to 15, then yeah, the right resistors should work...

[Jahmbie]

Originally Posted by Giant

i dont think you can use resistors to REDUCE resistance. hes talkin about going from 15 down to 8. resistors add resistance, so to go from 8 to 15, then yeah, the right resistors should work...

Wired in series adds resistance/impedance (2 @ 8 ohms series = 16 ohms)
Wired in parallel divides resistance/impedance (2 @ 16 ohms parallel = 8 ohms)

So...wire a resistor of at least 15/16 ohms in parallel to the 15/16 ohm speaker (BTW speakers are never exactly 4/8/16 ohms... more like 3.7/7.8/15 ohms) and the effective rating will be 8 ohms.

[pchilson]

Won't that resistor get hotter than fire?

[Giant]

Originally Posted by Jahmbie

Wired in series adds resistance/impedance (2 @ 8 ohms series = 16 ohms)
Wired in parallel divides resistance/impedance (2 @ 16 ohms parallel = 8 ohms)

So...wire a resistor of at least 15/16 ohms in parallel to the 15/16 ohm speaker (BTW speakers are never exactly 4/8/16 ohms... more like 3.7/7.8/15 ohms) and the effective rating will be 8 ohms.

you are correct sir. forgot about that parallel thing. my bad.

[Singin' Dave]

I just had an 8 ohm JBL D130F reconed by Ted Weber for 4 ohms to run with my bassmen and Bandmaster Reverb heads. As I understand it, it's pretty easy to specify voice coil ohmage to whatever you want when reconing. This would be distinct from wiring multiple speakers to certain impedences.

[51Esquire]

Resistors are not a good idea. First of all, you'll be wasting almost half of the amplifier's power in the resistor. I won't go into all of the other pitfalls using resistance in AC circuits.

[gtech]

And btw, you loose the same power no matter if the resistor is in series or in parallel. The resistor will dissipate half the power sent to the speaker/resistor circuit.

[KC]

if you're reconing it anyway, you can specify whatever impedance you want. No sweat.

[frank4001]

I just re-coned some 16 ohm jensens to 8 ohms..Cane out great. I got the baskets fairly cheap. Ended up costing about 90 bucks per. I'd go that rout again in a heartbeat because they came out great. What is really important is who is doing the work and with what parts. I happen to have some repair guys around here who are crazy good, into what they are doing, and have the right parts...

[celeste]

The voice coil gets replaced when you recone, so it is no problem to replace it with the rating you want.