DIY Scaled-up EBow-type Feedback Device

It has been awhile but I messed around with string exciters with Eurorack in the loop. It would be fun to try driving other objects. What worked best for me was using a permanent magnet wrapped with magnet wire when driving a string. I used an alnico rod magnet and 34AWG wire (1500 turns). The coil was driven with a DRV tile but any little amp will work.


While I do like my eBow, the “static” sound of it is one of the biggest issues I have with it. A wave shape hack for an eBow would be amazing.

Or, a multi string exciter with assignable wave shapes for each string.

I don’t think it’s made anymore, but I think Moog had a guitar that did something like that. Or it might be another company that I’m thinking of, that had this attachment for an acoustic guitar that worked on a similar principle but created “other” tones too.

1 Like

@pulplogic That’s super cool. Thanks for posting.


yeah, the moog guitar, which paul vo designed… 2008 or somethig. it was pretty fun.

Ah right, had no idea it was the same person.

It’s a shame that kind of thing didn’t get more traction. I guess it’s a pretty niche thing.

There’s also this sustainer called The Gizmo which used rotating wheels and spring loaded levers to excite the guitar strings



there’s also the duofluctus by sergey filatov, which produces sound from two strings being resonated by an alternating magnetic field, created by magnets on a spinning disc, which is then amplified via two pickups for a nice stereo effect.

I was very inspired by the duofluctus when making a sound sculpture built into a pillar together with a friend and collaborator last year. It had no microphones or pickups, only the box for acoustic amplification. this is what is looked like:

here’s what it sounded like:

the speed of the spinning disc enhances different overtones. the duofluctus has a knob which changes the speed. the sculpure I made had an arduino built in which varied the speed on the motor.


WOW! this is a great idea. You could probably also play a normal electric guitar with a similar spinning disk with magnets as a handheld device.

it is, isn’t it! sergey also made a small handheld device he calls magnetor using the same principle which can be seen in this video:


So the magnet is pulling at the strings each time it spins past, causing them to vibrate? Sounds amazing in the video.

exactly. very simple but clever design. glad you like it : )

ghost of thaddeus cahill

What kind of pickups are in the duofluctus, or what would be be suitable?

I have a friend looking to diy something like this.

Wow, I love how the different overtones creep out here and there. Would like to hear more.

don’t know the specifics, but it’s some type of single coil. make your own or buy some cheap ones and experiment!

@DanUK thanks : )
wish i had recorded the sound for a longer period of time, only have a 3 minute recording of it. made another one recently though, with a slightly different design and that didn’t drone but played overtonal bursts at regular interval, but i haven’t documented or recorded it yet. will try to get that done soon!


I have the wond V1, and watched Vo try to get v1 backers to commit to buying the v2. The V1 is a lot of fun with acoustic instruments with the right strings — loud, fast/responsive, and a ton of sound shaping power by just moving position along the string length. But the coils interact way too much with magnetic pickups to be a go-to with those instruments for me. After email communications with them, it became clear that this was a known issue for them that they were happy to brush under the rug during the Kickstarter campaign. I don’t know for others, but I wouldn’t be shocked if the lack of transparency around the V1’s known issues put off other V1 backers from supporting the V2. It felt like good tech, coupled with half baked product development, and an approach to customer trust that just isn’t sustainable with a crowdfunding business model.


That’s a bummer, particularly with something that seems like a cool idea like that.

I guess it’s a bit of a classic, too: crowdfunding isn’t sustainable as a cop-out from the challenge of developing a viable business model, product line, and consumer base.

1 Like

I fianlly managed to get a secondhand Piezothing ex Japanese auction site, charged it up & had a quick play yesterday and am really impressed with what it is capable of. It made light metal trays & biscuit tin lid shreik, but on timpani the resonating feedback of the skin was really beautiful. Varying the overall tuning of the timpani as well as touching the skin and applying pressure made the feedback drift with beautiful lag… I’ll record/video some…

I contacted the maker back in April asking to order a couple of them, and he said another batch was coming but I have never heard of any availability so have emailed him again now - will update this when know more.