PCB Routing: Tips & Tricks & Building Blocks

[Rixen]

an important factor in mechanical design of the board is how is it going to be mounted, therefore placement of mounting holes (if used).

I've seen too many boards where mounting is an afterthought or not even designed in at all.

Also, consideration of access- once everything is together, am I going to be able to get it apart again to service/tweak, still connected, without breaking wires or having to desolder parts

[vigilante397]

I'm currently working as a PCB design guy so I guess I can throw in my $.02 real quick.

For audio on a double-sided board I rarely if ever use two ground planes. It's just not necessary. The only reason I have ever found for using multiple ground planes in a many-layer board is because ideally every signal layer should be next to a plane. It doesn't matter if it's a power plane or a ground plane, but having a constant DC reference for signals is beneficial for reducing signal noise. For audio circuits like our stompboxes you still might not notice a difference, but for high-speed signals where controlled impedance becomes an issue this is essential. A design I'm working on right now has 12 layers (6 signal layers, 3 power planes, 3 ground planes), and I've been working on it for 3 weeks (1 week schematic + 2 weeks PCB layout) and am maybe 2/3 done. I love dealing with audio PCB's, because high speed signals are a headache

[POTL]

an important factor in mechanical design of the board is how is it going to be mounted, therefore placement of mounting holes (if used).

I've seen too many boards where mounting is an afterthought or not even designed in at all.

Also, consideration of access- once everything is together, am I going to be able to get it apart again to service/tweak, still connected, without breaking wires or having to desolder parts

Hi
I'm going to order the boards at the factory.
I use a lot of SMD components and output components for which I can not find an analog SMD.
All components are located on one side
The wires go only to 3PDT
Looks like a fee for darkglass

[POTL]

I'm currently working as a PCB design guy so I guess I can throw in my $.02 real quick.

For audio on a double-sided board I rarely if ever use two ground planes. It's just not necessary. The only reason I have ever found for using multiple ground planes in a many-layer board is because ideally every signal layer should be next to a plane. It doesn't matter if it's a power plane or a ground plane, but having a constant DC reference for signals is beneficial for reducing signal noise. For audio circuits like our stompboxes you still might not notice a difference, but for high-speed signals where controlled impedance becomes an issue this is essential. A design I'm working on right now has 12 layers (6 signal layers, 3 power planes, 3 ground planes), and I've been working on it for 3 weeks (1 week schematic + 2 weeks PCB layout) and am maybe 2/3 done. I love dealing with audio PCB's, because high speed signals are a headache

Thank you
If it does not do any harm, I'll stay with two ground planes
1) Sometimes this makes it easier to trace
2) I do not like how the board looks without a ground plane

[PRR]

> But why two ground layers?

Here's a sh*tty analogy.

Big apartment building. Run one set of drain pipes for the sinks, another set for the toilets, so the dirty water and DIRTY water are handled separately.

More extreme: an acid processing facility with employee potties. You might want separate pipes so waste acid can not come up the workers' bottoms.

In audio: a class AB power amp throws huge trash into the rails. The "ground" for this path has to be kept separate from most other grounds.

> audio/stompbox circuits, so not OVERLY complicated

Then like I'm doing in a house I am remodding. Shower sink and toilet all in one pipe. Within limits that is how all residential and much commercial plumbing is done. Small-audio can be equally un-complicated.