I have a (cheap) electric violin I use for practice. The violin requires a 9V battery to be amplified. After a couple of times I left the violin on (and hence I consumed the battery in like one night) I decided to buy a small AC adapter capable of 9V output. I amplified the violin this way for a while, connecting the violin with the adapter with a simple wire (3 meters of cable are more than enough for my room).

Yesterday, for some reason, I was not able to amplify the violin any more. The LED on the violin still turns on when it is connected to the adapter, but there seems to be no line out and the violin is not amplified, neither if I plug the headphones on the violin nor if I connect the violin with an external amplifier. I also tried a new 9V battery but the result is the same.

I'm not sure whether there is a difference between an AC adapter with 9V output and a 9V battery (I would say no, but I only have some notions in electronics, I'm definitely not an expert).

Did I actually ruin the electronic of the violin? What may be other problems that can cause this issue? I'm having some troubles in finding shops in my hometown that deal with electric violins, so I would appreciate if you could suggest some other test I can do myself to check whether the electronics is still working.

  • Post the specifications of the DC adaptor: Somewhere on it will be written its rated output voltage and amperage limit.
    – feetwet
    Nov 6, 2019 at 18:15

1 Answer 1


If depends on the adapter. A cheap adapter rated a fairly high power, say 9 Volts 1 Amp, will probably output 9 volts at 1 amp as it says on the box, but if your violin pickup only draws 0.1 amp (or even less, which is quite possible) the voltage may be more than 9 volts. It could be anything up to about 12.7 volts. That might or might not damage your violin - depending how "cheap" the violin electronics design is!

Another possibility is that you had a power surge (e.g. a lightning strike that hit the mains supply) which somehow "got through" you adapter and fried the violin electronics (but it left the LED working - that is probably independent of anything other electronics in the violin).

But the most likely cause is something mechanical, like a broken lead or loose connection from the violin pickup to the circuit board, or from the board to the output connectors, or the on/off switch is broken. Have a good look using a magnifying glass, and try waggling any wire connections about to see if that fixes it, or at least makes some clicking or crackling noises.

You could also try touching the connections to the pickup transducer (at both ends of the wires) with your finger - if you that produces a humming noise, the electronics is working but the connections are bad or the pickup itself may have failed.

A music shop that repairs electric guitars should be able to help. The basic principles are the same for an electric guitar (or an electronic pickup for an acoustic guitar) and an electric violin.

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