flat low z pickup

[Hans Bezemer]

I've build a prototype of a thin low impedance pickup.
Which is basically a regular pickup with only a few turns. The output is a lower then a regular pickup but when connected to a microphone input I get a very decent sound.

I used:
4x 25x5x3mm Neod. magnets
2x piece of 1.6mm cardboard
appr. AWG 44 / 0.05mm copper wire from a salvaged inductor

I've put two staples on the side of one piece of cardboard to use as soldering points. Then I glued the magnets on the first piece of cardboard. I let the magnets provide their own pressure by placing a metal piece under the cardboard. When the glue dried I glued on the second piece of cardboard.
I've wound 250 turns and got a dc resistance of 274 ohm.
I then soldered the ends of the wire and a microphone cable on the staples.
The height of the pickup is around 8mm, but could be made lower by using less (thicker) tape and smaller magnets.

The sound is very good and because of the balanced input their is hardly any noise / hum.
I'm planning to use a slightly thicker wire (0.1mm) and experiment with the number of turns, although I want to stay under the 300 ohms.

Hans

References:
http://music-electronics-forum.com/t38114/
http://music-electronics-forum.com/t5447/#post384975

[Jason Rodgers]

Nice work, Hans! I, too, have been following the low-Z pickup discussions on the MEF. They're on my list of pickup types to try out.

[Hans Bezemer]

I find it really interesting.
Next week I get some hpl-plate cutoffs of around 1/16 of a inch thickness, when using this as a bobbin I can get an pickup with a height under 3/16 and would fit under the strings without having to rout a cavity.

Of course it is done before: http://www.cigarboxnation.com/photo/100 ... e=activity

[Pete Halliday]

Can you post sound clips?

[rob bowen]

Yes...sound clips would be great ! Hans .... I want to mount a pickup in my acoustic build .... think this would pickup nylon classical strings?

[Jason Rodgers]

Rob, this is still a magnetic pickup, not a piezo or some other contact pickup: it needs metal strings.

[rob bowen]

Ahhhh ...thank you so much for telling me Jason.

[Hans Bezemer]

Can you post sound clips?

Alas, I just took of the strings of the instrument where I had the pickup mounted on. I'll make some clips, but it may take a while.

[michael o'malley]

where do you hide the transformer? Or am I misunderstanding the design?

[Michael James]

is that balanced, or single-ended?

[David King]

Michael,

I believe it's a balanced design - just like a low impedance dynamic microphone coil so you can plug it directly into a sound board or mic preamp via XLR etc.

[Hans Bezemer]

It is balanced indeed and there is no transformer (although I've made some with a single loop wire and a 1:500 current transformer, check here, here and here) .
I've made a couple of more pickups using 0,1 mm wire and around 800 turns and a DCR of 300 Ohm.
There's a short soundclip here