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Pilot Console Model #1239

Here are the details on the speakers. I was able to remove the grill by using a small punch and driving the small finish nails (2 per side x 4) further inward until the grill would slip off the cabinet. The woofer is sealed in it's own chamber which consists of the area underneath it as well as half the area under the tweeter/mid array. The sealed area of the woofer chamber is about 1.25 cubic feet less driver displacement. The two tweets and two mids are wired in series. The tweets appear to be sealed-back, but I might have felt a small hole in them. The mids are open back. I have no doubt the angled mounting and over-lapping cones does some very strange things to the dispersion pattern and couldn't be a good thing, but sometimes things that look terrible on paper can sound surprisingly good. I hope that's the case here. I have drawn the schematic and included below. All drivers are crossed using a simple 6dB circuit. The cabinet is quite solid with all panels measuring (a real) 3/4". There is no particle board - only solid walnut (grill frame) and veneered plywood.

As for my concern about the "Accoustimatic Turret" sealing properly, only the mounting shaft extends thru the sealed woofer enclosure, and I would assume there is some material underneath the bottom plywood that provides a seal when the large wing nut is tightened and pulls the assembly tight to the cabinet. The woofer is attached with 8 machine screws into blind nuts. I pressed and released the cone and it seems well dampened indicating a good seal.

The two crossover capacitors are wax sealed paper types and both measured slightly over spec and well within tolerance. I found it interesting that all drivers were wired reverse, with the negative input lead going the the positive terminal on the driver. All drivers had one terminal marked in red and I used a AA battery to verify the woofer is correctly marked. I guess there is no problem with them wired this way, it just seems unusual. The 12" woofer has a large, almost modern looking dustcap. I read somewhere on the Internet where someone said these have 4" voice coils. This is not true - I suppose they were guessing based on the cap size. The VC appears to be about 1-1/2".

I have not decided whether to replace the capacitors or not. They are currently perfectly functional, but it's not a simple task getting to them, so it might be prudent. I have also not listened to them either, which I think it's now time to do!

IMG_5071.JPG IMG_5072.JPG IMG_5074.JPG IMG_5075.JPG IMG_5077.JPG IMG_5078.JPG IMG_5079.JPG IMG_5083.JPG IMG_5084.JPG Crossover.jpg
 
I'd swap the caps. Its the ESR that I'd be slightly more concerned with than the value. If that increases, the output will drop. Also, you're there so it won't be easier.

Are the mids and tweeters actually mounted to anything? Almost looks like they're just laying in a "bucket".
 
Good point on the caps. The drivers are mounted by special magnet structures that are drilled and tapped, and then bolted to angle-cut blocks of wood.

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ah. that makes more sense. Still an interesting design. I wonder how much audible difference it makes if you rotate the drum without turning the whole speaker.
 
those are pretty cool. and given how difficult it was to figure out how to get the faces off, i'm not surprised they get short shrift these days. i'll be interested to see how different they sound with a recap, and if the drum-turning actually makes a difference as well.

beautiful console, too. they made some fine instruments back in the day.
 
I just got a pair of these from the thrift store. I will need to make new grills as the previous owner butchered the frame, and the veneer needs some work. From looking at you pics, it appears you access the xover through the woofer opening, which is good \ to know before I dive into these things. Interestingly, the grills have a baffle with a whole bunch of holes. I assume this is how they originally came although the reasoning behind his eludes me. These seem to be pretty rare as there is not much info on them. I was also shocked to see what was behind the grills after I got them off, all sorts of ugly, maybe not AR level of ugly but ugly never the less.
 
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