Amplify ALESIS Drum Kit Cymbal using TL082

[Menticol]

Hello guys!

I'm having some issues with my drum kit. The drum kit works as follows: The drum kit has a piezoelectric sensor attached to the pad (see attached photos). When the pad is hit the drum's "brain" module receives a pulse from the piezo sensor, presumably after passing through a voltage divider, and plays a sound. The volume of the played sound is somewhat proportional to the energy of the impact against the pad. The played sound is a pre-recorded file and has no resemblance of the received impact signal.

The problem is that the cymbals of my electronic drum kit are much quieter than the snare drum, and do require an excessive force to play at a reasonable volume, making the playing experience very strange.

Since the "brain" of my drum kit doesn't provide a way to adjust the sensitivity of each pad, I was thinking of putting a little OP amp between the piezoelectric sensor and the brain, with a potentiometer to adjust the gain.

I bought a TL082 Opamp and tried to follow another post on this forum where the OP also was trying to amplify a piezo signal. But my electronics knowledge is very basic and I'm not sure how to calculate the adequate resistor values to reach the specific gain/voltage, or how to run the TL082 on a single rail supply and not have the risk of frying the drumkit brain (the brain uses a singe rail 12V supply).

Attached is the output of the cymbal connected to an oscilloscope, showing the quieter signal and how much gain would be needed.

Any tips will be very appreciated

 

[Jake-moly]

Hey I am interested in this. So just to clarify. You ended up removing both resistors and found that the “perfect” setting on the POT was at 100k?

 

[Menticol]

Not exactly. The pot type "100K" allows you to dial in a 0 to 100K ohm value. After you find the perfect value you can either leave the pot there (like mine, looks very ugly) or measure at what resistance the pot was set in with a multimeter, and replace it with a fixed resistor. Sorry if my previous response was confusing.

Hey I am interested in this. So just to clarify. You ended up removing both resistors and found that the “perfect” setting on the POT was at 100k?

 

[Jake-moly]

Ok I re read it and understand now.
What about the original resistors? Have they both been removed and just using the pot?

 

[Menticol]

That's correct. I got rid of them, then connected the leads directly to the jack, as shown on the following photo. Very gruesome, but no SMD soldering required.

Amplify ALESIS Drum Kit Cymbal using TL082

Hello guys! I'm having some issues with my drum kit. The drum kit works as follows: The drum kit has a piezoelectric sensor attached to the pad (see attached photos). When the pad is hit the drum's "brain" module receives a pulse from the piezo sensor, presumably after passing through a voltage...

www.electro-tech-online.com

 

[Jake-moly]

Awesome. Parts are ordered. Did you do that with all the cymbals? Or just the high hat? This is for my son’s kit. I know nothing about drums. I am just a low life mechanic ha ha.

 

[Menticol]

Only the high hat, the other ones had a good volume / impact force ratio for my taste. That puzzles me, because I suppose the hi hat and cymbals have the exact same hardware. I guess it's a software bug. Oh don't worry, my musical experience is almost zero! But luckily there are lot of proper musicians here. Let us know your son's opinions about this hack

 

[Jake-moly]

Alright I ordered the parts removed both original resistors. (Amazon messed up and didn’t send me the pot.). So I tried a 47k resistor and my boy said it is way better. Thank you. I think I will put the pot in when we get it and fine tune it for him