AW12 1 dial speaker question

[Auroraoldradios]

Sunday I'm looking at an AW12 1 dial with single speaker in an early Tasman- the short leg cabinet. Seller says the speaker cone is damaged. What is the going rate to re-cone something like that? That will be a factor in how much I offer him. It's also missing the escutcheon.

[mike hadley]

Hi,

speakers are relatively easy to recone, it all depends if the voice coil and spider are ok,

otherwise you will be in for a coil rewind, not that bad to do just a little daunting first time round.

as for the escutcheon, if it's the same style as the aw15, I could plate you one from copper, not brass as the original but will look as good the original, please see an earlier post I placed on the subject,

Mike

[Auroraoldradios]

Here's the speaker. At least the chrome is good on both chassis. It appears to be a later AW12 single dial with AVC and single 12" speaker.

[mike hadley]

It looks like congratulations are in order, can you post a photo of the back of the speaker, once the type has been identified you can think about re coming,

the trick is carefully measuring the cone height, that measurement is between the basket flange and where the old cone joins the voice coil, luckily there people selling replacement cones,

my aw15 had no cone and a badly damaged voice coil, i made a new former from paper and epoxy and wound the coil with the correct gauge wire, the end result was a good sounding speaker that has Plenty of volume.

The repair is a lot easier than it first appears, the important thing is to get the voice coil gap shimmed to hold everything in place while you work on the cone.

mike

[Auroraoldradios]

Here's a couple of photos of the back. thanks, Dan

[mike hadley]

Ok,

the next step is to measure the cone height, to do this accurately you will have to remove the old cone, first remove the felt cardboard gasket, this may have a tendency to fall apart, if it does glue the card layers back together with white glue.

now the nasty part, remove the cone from the voice coil and spider assembly, be really careful that you don't damage the voice coil connection, on your Jensen speaker I think that the voice coil wires are terminated on the sides of the voice coil tube and not on the cone itself,

be particular about not getting dirt between the coil and pole piece as there is no dust cover on these speakers.

the gap can be cleaned with the sticky part cut off of a post it note, and a vacuum cleaner, be careful.

I think that your voice coil on this speaker is 2 inches.

next measure the depth of the old cone by using a straight edge placed across the speaker basket where the old cone was mounted and measure down to the old position where the original cone met the voice coil tube,

This is the height you will need,

I found that there is a little room for adjustment here,

don't forget to check the continuity of the old voice coil, now is a good time.

the replacement cone can be dropped in place and tried out for size, if the fitting is a little tight around the voice coil tube a gentle sanding with medium sandpaper is all it takes.

when affixing the new cone, gently shim the voice coil with some thin card or plastic sheet, polyester drawing film is good, make sure that the spider is at its neutral resting place and is not pushed in when you fit the shims,

this holds everything in situ as you work on the new cone.

apply a thin bead of slow setting epoxy to the edge of the cone where it meets the voice coil, drop the cone on and let this set, don't use too much glue here, your're looking for a continuous bead with no gaps,

slow setting epoxy is stronger than quick set,

after this has set, gently lift the edges of the cone and insert some small spacers this should lift the cone edge, thin dowel works here, apply rubber cement or similar to the cone edge and the mating basket surface, remove the spacers and and clamp with clothes pegs, when this glue has set remove the pegs,

the felt and cardboard gasket can now be re fitted back in its original place again glue with rubber cement.

that's about it, you should be good to go

hope this makes sense.

mike

[Auroraoldradios]

Thanks for the info. I have replaced foam surrounds on woofers so this has some similarities.

[mike hadley]

Dan;

looks like you have been down this route before, re-coming a speaker is just as easy,

pare you looking for an escutcheon?

mike

[Auroraoldradios]

Yes, the seller is pretty sure the escutcheon went AWOL. Here's a pic of where I'm at now. I found some cones on Ebay that may work. The voice coil is about 3.8 ohms.

[Auroraoldradios]

[mike hadley]

Dan,

this always looks drastic but you have nothing to loose, good to hear that your voice coil is intact, the as impedance is about 1.4 times the dc resistance.

the cone that I used was eBay number 331792020513, cone number 134905a this may or may not fit, check dimensions first, 

my speaker has a different spider, 

mike

[Auroraoldradios]

I saw your post about the repro escutcheons. They look very nice. I'd be willing to pay for one. Looks like the AW15 is the same or very similar. BTW, I ordered that same speaker cone. It was on my list of "hopefuls". Is anyone still keeping track of serial numbers? Mine is P148 and appears to be made towards the end of the production based on other info I've gathered from here.

[Kent King]

Thanks for the serial number. In this prefix, there are AW12 sets going up to P-234, so I'd gauge it as a "middle" set. However: if it went back to Scott for repair, they often made minor upgrades and improvements as part of the repair process. So earlier sets often show later revisions. It makes dating and doing accurate comparisons very difficult 80+ years later!

Kent