How to read op amps?

[frets]

Happy Sunday Guys,

It’s an away game so I have another week to build the amp. Yay!!

Anyway, I have a question about reading circuits. It didn’t come up in the guitar amp because all the pins were labeled. But as an example, here is a possible simple pedal circuit.




My question comes up as to the op amp.  The pins are not labeled.  Here is a pinout of a typical FET op amp.




Which pins are germaine to hooking up the op amp?  The + and -, is that Vcc + and - and then the circuit continues on by coming out the front of the triangle.  Is that 1OUT or 2OUT?  Very confusing to me.

I would like to push out with making more novel pedals but stuff like this stops me in my tracks.

As always, thanks guys!!😸

[MattB]

Oct 30, 2022 14:25:58 GMT -5 frets said:

My question comes up as to the op amp.  The pins are not labeled.  Here is a pinout of a typical FET op amp.

This is a dual op-amp. It's two separate op-amps, with shared power pins. It would be shown on a schematic as two separate halves, like this:





Note the IC1A and IC1B labels. That tells you these are two sides of the same part.
This shows the power pins added to the first half of the op-amp. Sometimes they aren't included at all, like in the schematic you posted above. Sometime you'll see schematics with power pins on both halves of the symbol.

If an op-amp symbol only has three connections they will be the two inputs, labelled with + and -, and the output at the pointy end.

The inputs aren't always drawn the same way up. sometimes the - is on top, sometimes the +.

[sumgai]

frets,


Matt pretty much covered it, just keep in mind that when you see these kinds of things, some assumptions are almost guaranteed. That's why you have us as a resource for your learning pleasure. 

But what I want to point out is that your posted circuit is a booster of some particular frequency, as detailed in the accompanying chart. I think this might pique your interest in controlling tone. While a battery inside of a guitar might not interest you, certainly one in a powered pedal should be within your wheelhouse, if I'm not mistaken.

HTH




sumgai

[thetragichero]

at that point might as well use an op amp gyrator circuit to get both boost and cut of a narrow (or wide depending on q) band of frequencies (look at the tone control section of the boss hm2 as that's usually my starting point for such a thing)

[frets]

Thanks guys,
I appreciate the help. Newey, I was interested in that simple circuit for a pedal but modifying it using a rotary switch to change cap values; thus, frequency boost changes. Simple enough for me to handle.

[newey]

Not me, thank MattB and sumgai.

[frets]

Oops, my apologies Sumgai😸

[Deleted]

Just edit your post and that way It makes Newey look crazy !!

I do it all the time <evil laugh time>

[newey]

Nov 2, 2022 7:33:42 GMT -5 @angellahash said:

that way It makes Newey look crazy !!

No need to confirm what everyone already knows . . .

[unreg]

Nov 2, 2022 11:09:14 GMT -5 newey said:

Nov 2, 2022 7:33:42 GMT -5 @angellahash said:

that way It makes Newey look crazy !!

No need to confirm what everyone already knows . . .

Pre-confirmed by you playing “Twinkle Twinkle Little Star” shirtless outside in the daylight on a snow day. How does your fingers work well in extreme cold?

[newey]

Pre-confirmed by you playing “Twinkle Twinkle Little Star”

I was most definitely NOT playing "Twinkle, Twinkle Little Star". That photo goes back 10 years or so, so I don't remember if I was playing something specific or just noodling around. But I don't know "Twinkle, Twinkle" so I would have to fake my way through that one.

My best guess as to the song, if there indeed was one, it was probably either "The Man Who Sold The World" or "Badge", those were things I was working on at the time.

How does your fingers work well in extreme cold?

Well, I wouldn't say it was extremely cold, probably around 20°F if I recall. But the bare feet got cold well before the fingers did!