My first layout from schematic. Please check?

[mattpocket]

In light of recent events, I have decided its time I learnt to read and interpret schems to make my own layouts. I have chosen TimE's LofoMofo.



Here is my layout:



Please let me know if it's right, the offboard wiring isnt particularly important, apart from the pots.

Thanks

Matt

[ezanker]

Your Grit pot lugs 1 and 3 may be wired backwards; otherwise it looks right to me.
EZ

[smnm]

The last 0.01uF cap and lug 3 of the vol pot are on the wrong rail - move em down one to the 3rd rail so they are in line with resistors, and it should work...

[ezanker]

smnm, i think it is right as is.  Lug 3 of vol only connects to the output cap in the schematic, nothing else.

[mattpocket]

That's what I thought as well... I think I got it right, and ezanker has confirmed this...

I got confused then, somehow thought i'd screwed up the whole thing, but no, I think it's good.

How do I decide which outside lug goes where? The schematic does not indicate this. I know the pot taper could, in effect (no pun intended), be backwards. But how do you know?

Thanks

[ezanker]

If they are not numbered on the schematic then it is not certain, but most of the schematics here use a convention that the lugs are numbered 1,2,3 from the bottom to the top:

  | 3
  |
  \
  /
  ---- 2
  \
  /
  |
  | 1

Then if you are looking at the back of the pot with all lugs pointing down, they are numbered 1,2,3 from right to left.

Just hook up the pot with clips first and if it turns the wrong way, reverse the outer lugs and you'll be fine.
EZ

[mattpocket]

Just hook up the pot with clips first and if it turns the wrong way, reverse the outer lugs and you'll be fine.
EZ

Yeah, thats what I thought!

[smnm]

The last 0.01uF cap ...

whoops - sorry about that, wrong again.

Simon

[tcobretti]

Not only does it look correct, but I would say you did a nice job.  Also, the post was IMO done correctly because you posted the layout and the schem.  People are less likely to help if they are expected to hunt for the schem.

[newbie builder]

Looks all good to me too! Great work.

[mattpocket]

I actually thought I did ok too, I was pretty chuffed with myself...

There are a couple of things with the more complicated circuits that I could do with some help on. In this schematic there are some IC's RC4558. They are just shown at triangles with a + and - and an output, but an IC has a load more pins, and on other schematics I have seen the pins numbered, but on some they are just shown like this. Can anyone enlighten me to what it means?



Also what are the triangles in the CMOS section labelled IND and INC?

Matt

[pyrop]

This should help you...


The xxx4558 has the same pin arrangement as the TL072 chip which is the standard dual op-amp layout.
Although you need to pay attention + & - inputs on the schematics as the schematic I have posted shows the + input at the top of the triangle & the one you posted has it at the bottom...

paulw

[smnm]

pyrop beat me to it, but here's another image of a typical arrangement with a 4558 that might help



Power and ground connections are assumed on most schematics

[mattpocket]

Are all IC layouts like this or is there any easy way to find out, i.e. searching for IC pinout that is required?

Matt

[MartyMart]

Good stuff matt
IC pinouts, more info in the DIY FAQ above or "search". those mentioned are for a dual opamp, but the
triangle symbol alone can be just a single opamp, such as TL071 or LM741 and their pinout
arrangement is NOT the same as a dual.
Good thing to do is if you're not 100% sure, go download a data sheet, which gives the pinout
and all specs for the particular opamp you want to use, BJT's and Fets also, as their three pins
can be totally different - It'll drive you crazy trying to guess the pinout and possibly damage an
expensive part !
MM.

[mattpocket]

When I see two triangles on a schem at different ends of the diagram, can they be the same IC?

Matt

[MartyMart]

When I see two triangles on a schem at different ends of the diagram, can they be the same IC?

Matt

Can be the same "dual" IC yes, unless it specifies 2x singles .
Dual just has two single IC's in the same sized package.
1 x triangle = 1 x single IC OR 1 x half of a dual IC
2 x triangles = 1 x dual IC OR 2 x single IC's
4 x triangles = 2 x dual IC's OR 1 x quad IC, such as a TLO74