ebow HELP!


last year i got a lot of help from you guys regarding an ebow circuit design. i ended up building a slightly modified 18v LM386-4 circuit like this ::

its an "electronic bow" for strings, basically a pickup and driver coil that feedback through a string, making it sustain a note for as long as the circuit is turned on. i made a micro-controlled electromagnetic harp that has 13 circuits like the above, switching strings on and off....

the project was great, but now i want to improve the circuit, and make it more powerful.

any thoughts on the TDA2030? i have it laying around, but don't really have the proper knowledge to implement it into a working design....

the LM386 distorted the signal a lot, and was only returning around 9v into the driver coil - resulting in very slow attacks on the tones of the string, or just no response at all.

the circuit needs to be compact to fit inside the new instrument, and not too expensive... powerful, for better response and less distortion.

any ideas? ANYTHING is helpful, my knowledge is limited, but im resilient as hell.


To make it more powerful you can add a transistor after the opamp which can switch a higher voltage feeding the output giving you a stronger response, although mke sure the output capacitor is rated for that voltage

OT - A bit anyway - What kind of music are you making with this ?

Duane B

@ winner, that sounds like a great idea... could you show me a quick example schematic? 4 times the energy would suffice... it would help out a great deal for version 2 of the instrument!!!

@duane :: this is a prototype running on a piano - prototype #2 on Vimeo

here is a picture of the final instrument, and some sound as well...

acoustic recording - http://snd.sc/LGy24i

live through 6 guitar amps, along with some processing, samples etc - http://snd.sc/OLgcQm

I was hoping for something a bit more Alice Coltrane :wink:

She playing piano and harp on this track -

Duane B

I can't make a shematic on my phone but get a suitable transistor(not sure how much 4x current is, idk what it is now), the base pin would go to the pin 5 thru a suitable base resistor, the collector to that cap(which should be larger if possible), the emmitter pin to ground
and connect that output coil to the higher supply voltage