Popsicle pickup for acoustic instrument

[Hans Bezemer]

I made a simple pickup to fit my modified baritone guitar (tuned it in fifths, and adjusted it accordingly).
My wife made me promise that it would be a "non-destructive" pickup, so no drilling allowed.

I came up with this:

I sandwiched two 25x5x3mm strong magnets between two popsicle sticks. I made a single loop around the magnets using some electric wire which I had lying around, keeping it in place with two tie wraps. I coupled the single loop with a 1:500 current transformer (Talema AS-104). Finally I soldered a microphone cable to the transformer.
The result is a low Z pickup with a balanced output suitable for a microphone input.
The distance between the two sticks is just a bit wider than the thickness of the top, with the use of two screws the pickup is clamped in the soundhole.

I've made two short soundclips, one with only a wee bit of reverb, and a second one with the highs rolled off around 2kHz.

I'm still pondering over a better way to retain the cable (besides using black tape instead of grey )

Merry Christmas!

Hans

[Jason Rodgers]

This is really cool, Hans! Do you have progress pictures, or could you take some closeups of the pickup from different angles?

[Hans Bezemer]

I've made a sideview shot.

I don't have any "building in progress" pictures, but it is a pretty straight forward process.
1. Predrilling the holes for the screws (the hole of the top stick is bigger then the hole in the other stick).
2. Gluing the magnets between the stick (I lay the stick on a metal ruler, so the magnet clamps itself down), and screw in the screws.
3. create a loop, adding the transformer and twisting and soldering the ends together
4. fastening the loop with tie wraps.
5. Soldering the wires

btw. in the US a CSE187L current transformer is more common, but does the same.

Hans

[Alan Peterson]

A current-sensing feedthrough transformer.... you loop the wire through the body instead of soldering it to leads coming off the component. Gotta admit that is pretty clever.

Now I want to try it myself.

[Hans Bezemer]

There's a very useful (but lengthy thread) on the MEF) about this subject (where I got this idea).
An advantage of a transformer with a build in primary loop (like the CSE187L) is that you can connect the ends of the thick wire loop directly to the primary loop, that would remove the kind of crude connection of the single loop. See here for an example.

One note: the primary loop has to be fixed or else it will get very microphonic (just as a regular pick ups needs potting to fix the copperwire).

[Glenn Ohman]

Thanks for sharing Hans. I've been pondering how to electrify an almost completed steel string parlor guitar build - I think this is the ticket.

Glenn