Hi !
So I’m trying to make a circuit to boost my guitar to synth level. @Ctorp showed me this schematic. I want to keep the boost section only. But the main problem is that I don’t know how. I was wondering :
-is it necessary to keep the portion circled in red (the offset section) ? can I delete it and plug the input right before R4 ?
-Is invertinput important for boost ?
-Also, can I cut the link between boost and attenuvert section to plug the output ? (small red circle)
-Is there a chip with less legs that does the same job as TL074/72 ? Because I don’t think I will need this many legs. (like 1,2,3,4,5 that’s it)
-Should I replace the 6 pins header (J6) by a 4 pins header?
You might want to take a look at Tom Whitwell’s Electrophon module, which is a synth module that has a guitar pickup mounted on the front. (You can wave magnets or electronic devices at it. Demo here:
and Github repo (converted for Kicad) here:
) Anyway, he uses two gain stages, a fixed 5x and a variable 1–26x. JP2 below is a connector to a panel potentiometer, JP1 connects to an output jack. He also has a fuzz circuit in there but you can ignore that unless you’re interested.
If you are going to bread board the circuit by Tom Whitwell, you might as well bread board the circuit you showed in the first post.
Leave out the left circled bit and build it using a TL071 and tap the output signal from the red circled tag on the right. A TL071 is a one op-amp chip. It is as big as a TL072, so you won’t save a lot of space using that.
Note: for amplification purposes C5, D1 and R7 are not important
TL071 pins:
pin 2 minus signal input of op-amp
pin 3 plus signal input of op-amp
pin 4 negative power supply
pin 6 output of opamp
pin 7 positive power supply
pin 8 not connected
pin 1 and 5 are for offset correction, you can ignore them for your application
Bread boarding this circuit as well seems more work, but you will be rewarded with learning something about op-amps. Also have a look at these op-amp tutorial videos by W2AEW.
