Oddball acoustic pickup?

[Mike Kolb]

Doing some TLC work on an '70's Harmony Model 566 (D35 knockoff) and someone along the line had installed a pickup that I've never seen before.

There's a brass slug mounted into the bridge and it terminates to a jack on the end of the guitar, but the jack is integral with an aluminum 'can' of some sort. No battery involved and no vol/tone controls either. 

It sounds alright, nothing special but decent. No markings of any kind on either the brass slug or the cylinder/jack combo.  Wondering if anyone can ID it? 

[Paul Verticchio]

I believe those were called "Hot Dots" and were marketed by either DiMarzio or Barcus Berry. They're simply encased piezo elements.

Hope that's a.) correct and b.) helpful

Have a good'un, Mike :)

[Mike Kolb]

Good thoughts ... but I sure can't find any Barcus Berry Hot-Dots that looked like this one.  Ditto for anything made by DiMarzio.  

Maybe it'll just have to remain a mystery!  The brass element itself seems to be the actual piezo (just by tapping it with a little screwdriver) and what's in the sealed 'can' is unknown, unless it's some sort of passive frequency network to smooth the output?   

My curiosity abounds ...but maybe I should default to the "if-it-ain't-broke-don't-worry-about-it" mode of thinking :)

[Paul Verticchio]

There were plenty of 'here today, gone tomorrow' transducer makers back then, Mike. It was a growing field and everybody came up with their version of "the world's best acoustic pickup".  Today's analogue would be the 145,753 clones of the Ibanez Tube Screamer that are available. Here's where old copies of Guitar Player Magazine come in handy. I love to review old issues (when I see them at flea markets) to see which "groundbreaking products" survived and which ones were "snake oily" colossal failures. Unfortunately, I gave away my 1969-1991 complete collection.

Now I DO know about that can. It's a standard shielding can which is still available from Switchcraft. http://www.switchcraft.com/productsummary.aspx?Parent=403

Some coaxing will allow you to separate the larger part of the can from the top. There should be alignment detents and a small screwdriver can be used as a gently manipulated can opener. The jack is "welded" to the can and if the jack has to be replaced, you have to drill out the old jack. The can is reusable.  I bet you'll only find a jack inside. There wasn't a whole lot of finesse with acoustic pickups back then.

I would concur that that dot pickup is appropriate for that particular guitar.

Let us know if you get a positive I.D. on that dot. It will be good historical info.

Best regards :)

[Kerry Krishna]

It's in the exact same camp as the HotDots anyway. These style of pickups were pretty darn easy to make from scratch. That is what this looks like.

[Mike Kolb]

Got it.... probably homemade.  OK, the mystery is "solved enough" for me!  I won't be digging-into the can for further clues as the whole package seems to work well-enough without my additional meddling!  

Thanks for the info, folks!