farvorite ways to start a pcb design?

Frequently asked question on the subject of designing, creating, producing printed boards, veroboards or perfboads and on point-to-point construction techniques.

Re: farvorite ways to start a pcb design?

Postby lolbou » 24 Jan 2011, 11:40

RnFR wrote:is that bad practice?
This I don't really know (no expert either! :wink: ), but I'd rather avoid it. It might be more important in higher gain and higher power stuff (like amps)...
RnFR wrote:the ground is running everywhere the pour is, it's not like it's running down wires. :?:
It is to me... Look at the righthand side 10k resistor shown on your PCB above: it's connected to ground. Now look at the 1M one, lefthand side. It's grounded too. But there are actually two path to go from one resistor to the other (on top of your ground loop, or on the bottom). Not really star-groundesque, right? Opening it somehow would solve this. I remember Francisco Pena from tonepad doing so...
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.
User avatar
lolbou
Old Solderhand
 
Posts: 2697
Joined: 18 Nov 2008, 22:38
Has thanked: 341 times
Have thanks: 230 times

Re: farvorite ways to start a pcb design?

Postby Greg » 24 Jan 2011, 12:33

lolbou wrote:
RnFR wrote:is that bad practice?
This I don't really know (no expert either! :wink: ), but I'd rather avoid it. It might be more important in higher gain and higher power stuff (like amps)...
RnFR wrote:the ground is running everywhere the pour is, it's not like it's running down wires. :?:
It is to me... Look at the righthand side 10k resistor shown on your PCB above: it's connected to ground. Now look at the 1M one, lefthand side. It's grounded too. But there are actually two path to go from one resistor to the other (on top of your ground loop, or on the bottom). Not really star-groundesque, right? Opening it somehow would solve this. I remember Francisco Pena from tonepad doing so...


I think the danger of grounding problems and ground loops in effects is sometimes overstated.. I certainly tie component ground points to the ground plane all the time.

For there to be a ground loop issue there must be a difference in potential between the grounding points.
I have to question whether there'd be any significant potential difference on the ground plane of a single and relatively small pcb..

As far as Star Grounding goes, I've always followed the advice of R.G.... this :
"In PCB based effects, you generally don't have to resort to star grounding on the effect (as I mention in my book on PCB layout)."
and this:
"... stompboxes are so small and have such small currents that
(a) the area of a ground loop is too small to pick up much radiation and
(b) the currents are so small compared to the conductivity of the grounds that you have little trouble."


I hope R.G. doesn't mind me quoting him on this.. or taking one comment out of a more complete explanation.
If he does, maybe he could leap in and explain it all better.
:thumbsup
culturejam wrote: We are equal opportunity exposure artists.
User avatar
Greg
Old Solderhand
 
Posts: 3324
Joined: 03 Nov 2007, 10:35
Location: Australia
Has thanked: 71 times
Have thanks: 192 times

Re: farvorite ways to start a pcb design?

Postby Dirk_Hendrik » 24 Jan 2011, 18:10

ppluis0 wrote:I agree with Dirk about the fact to keep signal tracks as short and direct as possible.


Eeeh, I did not exactly say that ;)
Keep high impedance lines as short as possble. Like the 2 resistors going to the inverting pin of an inverting opamp aplifier. When a high impedance pin is connnected to a low impedance source they can be longer if that makes the PCB layout easier.
Sorry. Plain out of planes.

http://www.dirk-hendrik.com
User avatar
Dirk_Hendrik
Old Solderhand
 
Posts: 4088
Joined: 03 Jul 2007, 09:44
Location: Old Amsterdam
Has thanked: 244 times
Have thanks: 971 times

Re: farvorite ways to start a pcb design?

Postby snmavronis » 24 Jan 2011, 18:55

Doesn't in theory making PCB traces wider (when possible) lower the impendance as well? I'm not even sure if it matters that much on these low voltage stompbox circuits.
Guitar > Boss NS2 Noise Suppressor > NS2 Send > MXR Custom Comp > Neo-Classic 741 Overdrive > NS2 Return/Output > VHT Special 6 Ultra Amp Input > Amp Send > MXR Carbon Copy Analog Delay > Boss RC3 Loop Station > Amp Return
User avatar
snmavronis
Solder Soldier
 
Posts: 209
Joined: 13 Jan 2010, 05:39
Location: Maryland, USA
Has thanked: 3 times
Have thanks: 19 times

Re: farvorite ways to start a pcb design?

Postby Duckman » 25 Jan 2011, 01:55

A very interesting article below
Point 12 talk about how wide traces reduces inductance and 15 about how corners increases it. Point 17 is about component orientation.

http://www.analog.com/library/analogdia ... ounce.html
User avatar
Duckman
Opamp Operator
 
Posts: 1526
Joined: 20 May 2009, 02:45
Has thanked: 364 times
Have thanks: 121 times

Re: farvorite ways to start a pcb design?

Postby snmavronis » 25 Jan 2011, 02:22

Ah, I always get impedance and inductance confused.
Guitar > Boss NS2 Noise Suppressor > NS2 Send > MXR Custom Comp > Neo-Classic 741 Overdrive > NS2 Return/Output > VHT Special 6 Ultra Amp Input > Amp Send > MXR Carbon Copy Analog Delay > Boss RC3 Loop Station > Amp Return
User avatar
snmavronis
Solder Soldier
 
Posts: 209
Joined: 13 Jan 2010, 05:39
Location: Maryland, USA
Has thanked: 3 times
Have thanks: 19 times

Re: farvorite ways to start a pcb design?

Postby Duckman » 25 Jan 2011, 05:41

User avatar
Duckman
Opamp Operator
 
Posts: 1526
Joined: 20 May 2009, 02:45
Has thanked: 364 times
Have thanks: 121 times

Previous

Return to Veroboard, Perfboard, PCB & Point-to-Point

Who is online

Users browsing this forum: No registered users and 1 guest