Noob: am I laying this board out right?

[benallison]

I'm still trying to wrap my head around schematics and electronics theory in general. So I thought I'd take a simple-ish schematic, and try laying it out for assembly on a stripboard.

I'm sure it's sloppy and could be more efficient, but is this even close to being right? What am I royally messing up?

BTW, there was no switch or led in schematic. I'm just focusing on translating it to a board layout.

The schematic I worked from:
http://www.roestudios.com/dump/gear/a_mbb.gif

The stripboard layout I made:
http://www.roestudios.com/dump/gear/render.gif

[raulgrell]

Although that's 100 times better than my first attempt, it doesn't look right.

The input jack doesn't take the signal anywhere, and from what I can tell, neither does the output jack. The 4.5V bias shouldn't actually go to the jacks - It's just meant to be signal and ground (and 9V to the ring of a stereo jack if you want it to turn off when no cable is plugged in)

I'm also not sure about the pin-out of your op-amps.
- If you use a TL072, you only need one, as it is a dual opamp. If you want to make the layout easier to make, you could use two single op-amps (eg TL071)
- You're not providing any power to the opamps. It isn't written on the schematic, so it makes sense that you forgot. You have to provide 9V to the op-amps, and you have to make a bias network for you to achieve the 4.5V

Basically, you should look up: op-amp pinouts and bias networks. Here's a nice page: http://www.generalguitargadgets.com/richardo/distortion/index.html

[raulgrell]

Sorry, double post.

[frequencycentral]

This will get you the v-ref not shown in your schemo - I stole it from the MXR Distortion+

Put 9v in the top, 4.5v comes out the bottom.

[benallison]

Thanks gents!

Yeah op amp pins are making my brain explode.

"There's 8... but on the schem, there's only 3... BLAM!"

[leonhendrix]

EDIT: Already been said... sorry 





Yeah The TL072 has been split in two for the schem 

..anyway this one is easier to understand dealing with the IC pins.

[benallison]

Ok...

lenonhendrix, that helps a bunch. What's the difference between the tiny circle termination and the 1/2 vcc? Also, what's the -Bar (?) thing that the input goes to?

frequencycentral; ok, so the + from my DC in goes to V+, and the - goes to ground?

So with input/output, sleeve always goes to voltage, and tip always goes to ground?

[frequencycentral]

frequencycentral; ok, so the + from my DC in goes to V+, and the - goes to ground?

Correct, + from DC goes to V+, - goes to ground.

So with input/output, sleeve always goes to voltage, and tip always goes to ground?

Not quite sure what you are asking here - are you talking about a DC input socket - if so you are correct.

[benallison]

Sorry. I meant of the 1/4" input and output jacks.

[frequencycentral]

Sorry. I meant of the 1/4" input and output jacks.

Nope - other way around - sleeve is ground, tip is your signal.

[benallison]

Ok. Attempt two:

Original schematic:
http://www.roestudios.com/dump/gear/a_mbb.gif

My layout, version 2
http://www.roestudios.com/dump/gear/render-b.jpg

Any closer?

This page REALLY helped my understand opamp pins: http://www.diystompboxes.com/pedals/FAQ.html

There's a good walkthrough right at the bottom.

[dxm1]

1) I'm kinda confused with the horizontally placed resistors - are there trace cuts under each?  If so, they are hard to see in the rendered JPG... It is usually a good idea to point out all trace cuts in comments on the layout so folks won't miss them.

2) The TIP of the input jack looks like it goes to +9V, unless there is a trace cut under R3... It should go to the junction of a 2M2 resistor (R5?) and a 0.01uF cap (c3?).  That would put it on row D.

[benallison]

Thanks dxm 1!

There are trace cuts under all of the horizontally placed items.

About the tip, i just thought that sleeve was ground and tip was signal... but I guess that doesn't mean that tip is directly related to voltage. R5 is 2M2 and C3 is .01uf as you suggested they should be. So input goes just before that R5 or by junction did you mean it goes in between the two?

Does the output tip stays where it is?

And why does input tip go there (my theory is severely poor -- as I said, I'm a noob!).

[Jered]

  Please don't take this the wrong way, but your going about this all wrong. Start with something simple like a single transistor booster. That way you will learn about input/output, switch wiring, power, adding an LED, etc. Then do a layout for that, and get it working.
  Over the years I've seen a lot of new guys try to do what your doing and they just get frustrated and discouraged, and eventually give up.
  You want to understand the basics, as you do in any new semi-technical adventure. Every bit of info you need to start is in the beginers section and you will be glad you did. It will make building pedals so much more enjoyable.
  And of course, as I'm sure you already know, if you have any questions, just ask.
  Jered