new to pcb design

Did you want to put the switch for power on the PCB? Just checking...

Also why only 9V? Just dont label it.

You have no Rled. Poof.... Do red LEDs emit red smoke (joke, and no they dont)

If you rotate the power input connection 90* you can shorten the power input traces significantly. Depending on what case you put this in it may allow for neater wiring too.

The trace from C1a to pin 3 can be shortened significantly by going directly to the op amp (between the opamp and those resistors) rather than looping all over the board.

If you flip the positions of c2a and r2a(? the 100K resistor next to c2a) you can shorten the trace from the pot to it, and avoid a few turns. This may also allow you better ground plane fill.

The trace from the pin 7 output of the opamp does not have to go under the pot like you did. Route it in front of the pot (between the pot and the front of the case...) After this, the trace from the front/center pin of the pot can be routed more directly to c1a 

Have you considered adding pads for small power supply decoupling caps right near the op-amps? 

edited:

on JP2 if you ground the center pin out towards the top (away from the opamp/resistors) you can get a more direct path from r3a3 (I think thats the part) to pin 3.

Your input/output jacks and volume control may need to

be moved closer to the edge of the board if you want them

to be available outside of the case...

Try running DRC and I think you'll probably find quite a few issues.

It is usual practice, on a single sided board, to put the traces on the bottom

of the board and the components on top. Makes it easier to solder that way.

On a double sided board, the general rule is to put the traces running one

way on the top and the other way on the bottom (say left to right on bottom

and front to back on top). For your application, if you are going to use a

double sided board, put as many of the traces as possible on the bottom

and use the top as a ground plain. It is OK to put a few traces on the ground plain

side to jump over something if you need to. The goal is to keep traces as

short as possible.

Try to avoid sharp corners, use rounded corners. Keep traces the same width

all the way through the radius.

Hope this helps!

We'd love to see how you improve the design.

When you are in the main window, set your Trace Width and Miter to the same value.

If you want to practice, just start a new board with no schematic and practice with

the "wire" function. Sometimes it is faster to just do the whole project this way but

you will not have any cross check to your schematic.

Good luck! 
 

Quote:

Originally Posted by tamu 

Thanks very much. very useful info. however I still need to learn and practice.

BTW having the ground on one side makes alot sense.  I still couldnt fully understand the functions in eagle. I think its gonna take a bit more fiddling.

 

Rounded corners; do I do it in the design rules or in autorouter setup screen?

 

also I totally forgot to add a switch

 

another thing that I was thinking is to remove the pot and jacks from the board and just put terminals or etc instead.

 

Will try to come up with a different one tonite. will do as much as routing on the bottom side and try to have them on one-sided board. if it becomes too messy Ill try having the ground on top side.

 

thanks again. much appreciated

In a side note to your CMoy design...

It might be easier and just as effective

to use a TLE2426 in place of your resistor

divider and Op Amp virtual ground.

It uses much less power and is enough

for a single Op Amp like you have.

What you have is not wrong, it is just

more than you need.

Here is a CMoy I did last year.

The top layer is a ground plain.

All the signal and power traces

are on the bottom. I wasn't sure

what kind of case I was going to

use so I made a jacks off board.

The chip at the left is a Dip 8 TLE2426.

Doing a PCB is an iterative process.  Place, route, decide it sucks, rip-up everything, place, route, decide some parts suck, rip them up, re-route. Repeat.

Try and reduce the cuts in your ground plane.  There is a few places I see where your ground plane is no better than a trace due to other traces causing bottlenecks.  You also have some traces that could be a lot shorter.  Take a look at pin 3 of OP1 for example.

I haven't tried to layout a single sided board, but if you look at the "professional" ones, they use jumpers to try and reduce the lengths of traces and cuts in the ground plane.

http://www.alternatezone.com/electronics/pcbdesign.htm