Alan .. first of all thank you... second you are completely right and i figured that out by discussion with members .. i was fascinated with the Pro look of the PCBs of Sprint .. and then i realized that Eagle Can do the same but i just simply still can't achive that pro look .. i'm using Eagle for years since Version 4.0 but discovered i'm not professional yet....
about the Track width exactly as you said i need to read a lot to answer .. that's why i asked that question to have a quick answer or tip to just be able to design right amp pcb ....
Regards
M.H
Sorry, there is no quick answer on the loop thing. You have to look at the pcb. Layout a simple stage, post it. I can look at it for you. It comes with experience to look at the pcb. I troubleshoot layout problem with eyes.
One point ground is not solution for all. I actually fixed a Twin Reverb in another forum because they guy put the return of the driver stage onto the star ground of the preamp. I would be very very careful to work on the star ground. One wrong star and is trouble.
I've had to use many of the high-end programs for work and played with the rest over the years to pick something for home use.
DIPtrace is my current favorite and I recommend that for DIYers, primarily because pf the integrated schematic capture.
However, Sprint Layout is, without question, the easiest/fastest to learn & use PCB layout program I've ever seen.
For folks that don't care about integrated schematic capture, Sprint Layout is impossible to resist.
Bottom line is just pick a tool that has the price and support options you want and STICK WITH IT.
All these tools have a learning curve; the fun begins once you get over that hump.
And after you play with enough of them, you'll find they are more similar than different once you get over the hump.
Any of the tools can be used to make a great board; the tool you use is NOT the "secret sauce", YOU are.
mlloyd1
DIPtrace is my current favorite and I recommend that for DIYers, primarily because pf the integrated schematic capture.
However, Sprint Layout is, without question, the easiest/fastest to learn & use PCB layout program I've ever seen.
For folks that don't care about integrated schematic capture, Sprint Layout is impossible to resist.
Bottom line is just pick a tool that has the price and support options you want and STICK WITH IT.
All these tools have a learning curve; the fun begins once you get over that hump.
And after you play with enough of them, you'll find they are more similar than different once you get over the hump.
Any of the tools can be used to make a great board; the tool you use is NOT the "secret sauce", YOU are.
mlloyd1
You too ... can be like this - become the circuit
.That was humor .... consider grounding. Mentally visualize each signal
flowing back to a common point.
Would you want a peaceful stream entering the maelstrom of a
high current decoupling return (no longer peaceful) ?
If it had to ... would it not be best to do so at a point where
two " maelstrom's" cancelled each other out.
That describes a star ground with analogies. Visualize that.
OS
You too ... can be like this - become the circuit
That was humor .... consider grounding. Mentally visualize each signal
flowing back to a common point.
Would you want a peaceful stream entering the maelstrom of a
high current decoupling return (no longer peaceful) ?
If it had to ... would it not be best to do so at a point where
two " maelstrom's" cancelled each other out.
That describes a star ground with analogies. Visualize that.
OS
Yes, visualizing is the best way to describe it. Think as if you are the current, how does it want to go. It is hard to come up with a cook book formula how to route ground and power, visualization is important.
The important thing to get very good with the pcb program are the padstacks and creating copper planes. Forget about auto routing, you don't need it for audio boards. I never use auto routing even for complicated digital boards. They are too stupid and you end up wasting more time checking and correcting. Practice, make it become part of you. I can route so fast I am sure I save time if I have to check and correct the auto route. they are very stupid.
The key to a good board design is component placement, that drive the whole design. In a good layout, you hardly see any trace because most connections are point to point. Look at post #5602, it's my design of the OPS section. http://www.diyaudio.com/forums/solid-state/171159-bob-cordells-power-amplifier-book-561.html
I use power and ground planes and output planes to lower the loop area. If you look at the signal traces, there are only 4 long traces. Two have to drive all the big transistors, has to be long to reach all 10 of the transistors. the other two traces are the +ve and -ve input that have to drive the bias spreader and the pre-drivers. Other than that, all the other traces are short, most are point to point.
To me, the best layout is one that looks very simple, very few traces that you can see. But if you look at my schematic, it's not a simple circuit by any stretch. If you see a lot of traces running around, then you have a lot more chances of creating current loops.
The key to a good board design is component placement, that drive the whole design. In a good layout, you hardly see any trace because most connections are point to point. Look at post #5602, it's my design of the OPS section. http://www.diyaudio.com/forums/solid-state/171159-bob-cordells-power-amplifier-book-561.html
I use power and ground planes and output planes to lower the loop area. If you look at the signal traces, there are only 4 long traces. Two have to drive all the big transistors, has to be long to reach all 10 of the transistors. the other two traces are the +ve and -ve input that have to drive the bias spreader and the pre-drivers. Other than that, all the other traces are short, most are point to point.
To me, the best layout is one that looks very simple, very few traces that you can see. But if you look at my schematic, it's not a simple circuit by any stretch. If you see a lot of traces running around, then you have a lot more chances of creating current loops.
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You too ... can be like this - become the circuit
That was humor .... consider grounding. Mentally visualize each signal
flowing back to a common point.
Would you want a peaceful stream entering the maelstrom of a
high current decoupling return (no longer peaceful) ?
If it had to ... would it not be best to do so at a point where
two " maelstrom's" cancelled each other out.
That describes a star ground with analogies. Visualize that.
OS
OS ... Your humor is the best explain i have ever heard .... your words gone the high way to my brain ... i realy love that ..thanks a lot you are the man
Regards
M.H
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Alan i like your design a lot .. it's neat , space efficient and look so simple while it's not .... just let make a good use of your experience wit heagle and ask a question in eagle ... how can i make such thick tracks like if they were planes ? does they really are ? ... if i just change the width of the track it may interfere with the next one... and if it's a plane for that signal such that in ground planes how can i make many signal planes say one for ground , one for -ve rail one for +ve rail and one for output signal??
Regards
M.H
Audio pcb's need very careful grounding.
I got caught out seriously wit ha USB mixer I designed.
I just got my CAD software to convert to a pcb then I just connected up tracks as they came. The result was 1 volt peak to peak of hum on the output with the input shorted !
The charging impulses into the smoothing capacitors were modulating the ground line and injecting hum everywhere.
I re-laid out the pcb totally separating the power supply from the audio.
I used star grounding as much as I could and the new pcb was much better.
You really need a decent PCBCAD package. One that does schematic to pcb conversion.
Design rules are also a must. One track touching another etc and the pcb is junk.
I also like forward annotation for if I make changes to the schematic, this updates the pcb for me.
I got caught out seriously wit ha USB mixer I designed.
I just got my CAD software to convert to a pcb then I just connected up tracks as they came. The result was 1 volt peak to peak of hum on the output with the input shorted !
The charging impulses into the smoothing capacitors were modulating the ground line and injecting hum everywhere.
I re-laid out the pcb totally separating the power supply from the audio.
I used star grounding as much as I could and the new pcb was much better.
You really need a decent PCBCAD package. One that does schematic to pcb conversion.
Design rules are also a must. One track touching another etc and the pcb is junk.
I also like forward annotation for if I make changes to the schematic, this updates the pcb for me.
Those are not done by routing traces, those are copper pour.
I have not been using Eagle for a while, I just learned it and layout one board before. So I am not going to steer you wrong on anything.
That's the reason I mentioned before the important two things to be expert at are copper pour and padstack. you need to learn how to nip and tuck the coppor pour to go however which way you want it to. Learn how to set up clearance from pads. How to make sure the pour continuation between pads so you don't accidentally create a big rip on the copper plane because of too many pads in the same area. This is mighty important. You always have to look at the plane to made sure there is no accidental cut.
You have to know and be very careful in the padstack of EACH component. Make sure you have large enough drill size, enough meat around the drill hole to make the pad stronger. Always check the thermal relief, make sure you have at least 3 spokes connected to the ground plane if not all 4. I use 25mils spoke width for small thermal and 40 for large.
Last and most important, it's not the routing, it's the component placement that set the routing and the tone of the overall layout. For example, the OPS board shown, I spend over two days just dudoling with the component placements. After the placement, the first past routine is less than 30mins. For some routing on different boards, I can complete the routing in 5 minutes.
Don't hesitate to rib up all the routing even you finish and redo the placement again. a lot of times, even the placement looks good, some how, the routing end up cutting up the ground and power plane too much. Those might not be apparent just looking at the placement without the route. don't compromise, be patient and never hesitate to start over again. After you do the first attempt, you have a much better feel of the layout, the second try is going to talk less than 1/4 the time of the first try. Never compromise. Biggest mistake of a lot of pcb designer I encountered was they were too lazy to start over and try to patch it instead.
I assume you are doing 2 layers as it's a lot cheaper to fab. Try to put power planes and as much traces on the bottom, put the ground plane on the top layer where it is the most effective in shielding. Whenever you put a trace on the top layer, check very careful on the continuation of the power plane. You do not want to have over 1/2" cut on the ground plane. If so, the current has to go around the cut to complete the circuit and you create a loop.
keep doing layout, you'll gain experience and get good at it. I really like layout pcb. This is my jigsaw puzzle, but instead of putting up a picture, I design with the best circuit in mind. I was the manager of engineering before and I had pcb designer working for me. BUT I layout all my own boards. I like it that much. It's the biggest enjoyment in my job. I even got contracted out to KLA tencor to design and layout a test pcb for their 4G pixels CCD chip in 2003.
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Thank you all ... these all are great advices and nots to learn ..... but my question for you "jwilhelm" i do copper pours by making ground plane all over the pcb ... then i decided not to make a ground plane to can obtain the star ground ... is there a special way to make many power signal planes or just make many power signals planes
jwilhelm ... In Eagle .. if you use sprint just tell me the procedure i think it's all the same
Regards
M.H
I got very used to EasyPC, then found it wasn't compatible with Vista/win7.
I then switched to ExpressPCB. I have used Ultiboard which was nice too.
Now I'm using Design Spark6, mainly as its so similar to EasyPC with the 3D board view of Ultiboard, but free.
I have no idea if it converts schematic to layout, if so ive never found put how to use it.
Never used Eagle or Sprint. Maybe I'm missing out?
EasyPC or Design Spark seems to work well enough for me (even ExpressPCB is good for free software)
I then switched to ExpressPCB. I have used Ultiboard which was nice too.
Now I'm using Design Spark6, mainly as its so similar to EasyPC with the 3D board view of Ultiboard, but free.
I have no idea if it converts schematic to layout, if so ive never found put how to use it.
Never used Eagle or Sprint. Maybe I'm missing out?
EasyPC or Design Spark seems to work well enough for me (even ExpressPCB is good for free software)
So i just make many planes and name each one to the power signal i want ... why i didn't do that before
... i used to make a ground plane never thought to make many plans .. but i think it's made this wayThank you
Regards
M.H
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