Stagg Electric Uke Hack : Fixing the Buzz

Not too far back I fitted a piezo pickup to one of my ukuleles. It was a cheap and fairly painless exercise. Today I’m going to talk about some of the mechanics of amping the instrument.

First let’s get some technical stuff out of the way:

“Piezoelectric fields result predominantly

from atomic layer displacements along

the nanowire axis within both the core

and shell materials.”

– American Chemical Society

Piezo pickups (AKA Piezoelectric pickups) work in a slightly different way to magnetic pickups. Magnetic pickups rely upon vibrating steel strings affecting the pickup’s electromagnetic field whereas piezo pickups rely upon changes in pressure affecting the pickup’s ceramic core. So in a nutshell, Piezo pickups are reliant upon picking up vibration through contact with the strings. This is why you fit piezo pickups under an instrument’s saddle. And this is why you need a nice tight fit for the piezo to work at its best.

A feature of piezo pickups is that they output a far higher frequency range than magnetic pickups. You need to manage this if you want to get a good sound out of an amplifier. Piezo pickups are famous for producing clipping and buzz. And whilst this might sound ideal if your only interest is in recording punk ukulele, it is actually far from ideal.

If your piezo is passive (i.e. no pre-amp), then the job is all yours to fix. I’ve never managed to get a good sound out of an instrument with a passive piezo. If you have a pre-amp as I have with the UK2000, then you might be lucky.

The conventional solution to this problem lies in a device called a Direct Injection box. There are different flavours of DI box available, but they all roughly do the same thing: to match input/output impedence between pickup and amp, and to deal with pickup grounding issues. I’ve never owned a DI Box and they’re expensive!

A selection of DI Boxes

The King Uke approach to this problem is to experiment with less conventional solutions.

It takes a round 5 seconds when investigating a lot of pickup problems to discover that most hums, pops, clicks and buzzes can be solved by touching your finger onto something metal on your instrument. On my ukulele I can cut out all inteference by touching the jack socket or jack lead plug with human flesh. This is usually a good indicator that I’ve got a grounding problem. Whilst it’s fairly easy to fix grounding issues with magnetic pickups, I haven’t come up with a long term way of doing it with a piezo.

My solution then is to simply make the dirty hack a bit easier; Pressing flesh to the jack socket is not easy to do while you’re on your knees delivering electric ukulele retribution. In the past I’ve used bits of wire, tin foil, basically anything metal to hand that I can use to run a line between the instrument and my body. One end usually ends up hooked inside my pants, but let’s not dwell on that right now…

Today I present a new, more elegant version of the dirty hack.

I recently bought myself an anti-static wristband. It cost 99p off ebay and I had to wait about a month for it to arrive from Hong Kong. And it works!

Anti-static wristband
Wired up and dangerous!

And finally…

Whilst I hope that this post has made you smile, I also hope that it offers some insight to anyone who might be struggling with similar problems. What I’d really like – and the main reason for this post – is for some of the cleverer people out there in internetland to share some specialist knowledge. If you’ve got something to say… If you know how to tame the piezo… then please let me know!

12 thoughts on “Stagg Electric Uke Hack : Fixing the Buzz

  1. I’m not an expert, but I’ve been inspired by your posts to buy the same pre-amp and to go down the same road as you to get an amped ukulele.

    At one point you said you were going to update the site with info on how the uke sounds, I’m very interested to learn how it sounds, so if you have any information or views on how it’s going (appreciate you’re now busy building an electric uke from scratch, though), it would be greatly appreciated.

  2. I’m not an expert either Charlie! Thanks for commenting. You should do this! If I was doing this project again I think that I would invest in a more expensive piezo… definitely, if I was putting it into an expensive uke. I reckon you can get a better sound and it probably is all down to how much money you’re willing to spend. I’m going to look into doing a soundcheck on this amp for you, maybe even today. Watch this space…

  3. Hello again! Thanks very much for the sound test. It sounds great. My UK-2000 has just arrived, and I’m just trying to test it out before getting a drill out or anything. However, I’m not picking up anything. Is there an on-switch or something? The battery’s in, the volume’s maxed, the pick-up and jack are plugged in (the jack is connecting to an M-Audio Audio Buddy), but even tapping the piezo pickup doesn’t seem to be producing any signal at the other end. There’s nothing obvious I’m missing, I suppose? It could be a dead battery – I’ll see if I can find another battery to try…

    • That’s sounding very odd Charlie. This may be stupid, but I seem to remember not really knowing which was min and max on the volume. Try in the middle on all of the sliders just to make sure it’s not that. There is a low battery indicator. It flashes when I plug the jack in. Is yours doing this? Definitely try another battery. I’m still using the one supplied with it. I haven’t used an Audio Buddy before, but I can’t think that this would be the problem. I’ll ask around and post back anything I come up with…

  4. Brilliant! It’s really working! That’s amazing!

    Of course, the smoke alarm now has no battery, but I’m sure that won’t be a problem. The battery’s much happier in the pre-amp.

    • If you’re feeling brave – why not stick some photos of your project together and we can put them up here. Either way would like to hear an update on how your one ends up sounding!
      Rock and Roll!!!!

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