Watkins Woofer Issue - VC

[tlcasper]

A while back I purchased some spare and replacement drivers for my QLS 1 speakers. A very reasonable deal was reached, and we were both happy. The seller then mentioned he had a spare, but single Watkins woofer that he wouldn't need anymore. He offered it for a great price and I bought it too. It is paper coned and has the smaller magnet, but it would make a good back up, or I could sell it.
In looking it over closer than when I purchased it, I put the meter on the VC leads, and both sides measured 4.9.
Does anyone know what would cause this, and if it's repairable?

Thanks.

 

[slimpikkins]

That's a tough one. May have always been that way. Is it a Watkins for sure? There are other dvc woofers out there but I believe the Watkins is the only one with two different impedances on their vc. Others are for applications which right and left channels can be hooked up to a single speaker. Maybe a picture would help.

I wonder if the windings have shorted against one another making them read the same...
Jim

 

[tlcasper]

It looks like other small magnet Watkins woofers that I've seen photos of.

 

[slimpikkins]

Yes, sure does look like one. Maybe someone else will chime in.

 

[tubed]

The unpainted magnet is something I haven't come across, yet.
The small magnet Watkins I seen always seem to have some nickel sized plates soldered on to the back of the basket.
Other than that, perhaps the driver was already repaired except with equal valued voice coils

 

[slimpikkins]

You could take the speaker apart and pluck a winding or two off one coil. That would decrease impedance on that coil. Not sure if that would change anything else though...it would be a tricky project.

 

[tlcasper]

It has been newly refoamed too.

 

[toxcrusadr]

How different are they supposed to be? I'm not up on Watkins woofers. I assume from the above posts that no one here thinks they can measure the same DCR and still be OK?

How are the solder connections at the terminals?

Are you sure your meter is OK?

 

[tlcasper]

How different are they supposed to be? I'm not up on Watkins woofers. I assume from the above posts that no one here thinks they can measure the same DCR and still be OK?

How are the solder connections at the terminals?

Are you sure your meter is OK?

They are listed as 2ohm and 4ohm, though from what I have read, 2.5 and 5 are what most people measure.

The solder connections seem fine, and both sides measuring exactly the same.

I have 4 other 12" Watkins woofers that all measure correctly with my meter. So I feel it's a possibly damaged VC.

 

[tlcasper]

The unpainted magnet is something I haven't come across, yet.
The small magnet Watkins I seen always seem to have some nickel sized plates soldered on to the back of the basket.
Other than that, perhaps the driver was already repaired except with equal valued voice coilsView attachment 823975

Here is an AK thread with 2 small magnet Watkins that don't have the plates in your photo. His are two different colours though.
http://audiokarma.org/forums/index.php?threads/watkins-woofers-in-quantum-line.87469/page-3
It has been refoamed so a bad repair is not impossible.

Dave

 

[tubed]

Try measuring across VC1(+) to VC2(-) to eliminate the idea of a short between the two.

The only thing I can think of would be a factory goof or a wrong headed voice coil replacement.

 

[tlcasper]

When I measure across VC1+ to VC2-, I get no reading.

 

[tubed]

When I measure across VC1+ to VC2-, I get no reading.

Das ist gut,
no short but one vc reads too high for the Watkins circuit