SparkFun Forums

[leon_heller]

A good autorouter wouldn't work very well on a board like that, you should be routing it manually. Your use of the (rather poor) Eagle autorouter explains many of the problems with your layout.

Leon

[bigglez]

Your use of the (rather poor) Eagle autorouter explains many of the problems with your layout.

Could you suggest a better PCB layout tool?

[leon_heller]

Eagle will get the job done, albeit with some difficulty, but autorouting a board like that is a mistake. There are much better tools, of course, like the Pulsonix software I use. Pulsonix uses the Electra autorouter, which is available for Eagle. It's very good, but I wouldn't use it for that type of board.

Leon

[bigglez]

There are much better tools, of course, like the Pulsonix software I use. Pulsonix uses the Electra autorouter, which is available for Eagle.

Is this Pulsonix free? Is this Electra free?
If not what does it cost?

[FartingMonkey92]

There are much better tools, of course, like the Pulsonix software I use. Pulsonix uses the Electra autorouter, which is available for Eagle.

Is this Pulsonix free? Is this Electra free?
If not what does it cost?

Lol, here we go again...

"And yes, I will still need caps and a big transformer, but those can be case mounted, they dont need to be mounted on the board"

That's why i said "in your enclosure"...

[leon_heller]

There are much better tools, of course, like the Pulsonix software I use. Pulsonix uses the Electra autorouter, which is available for Eagle.

Is this Pulsonix free? Is this Electra free?
If not what does it cost?

Pulsonix starts at about twice the price of Eagle Professional (2,000 GBP, IIRC, vs $1494 for Eagle). It's good value, as designs can typically be completed in a fraction of the time it takes with Eagle.

http://www.pulsonix.com

Electra starts at $645:

http://www.connecteda.com/

It's far better than the Eagle autorouter, typically routing to 100% completion even on complex boards.

I've just imported the design into Pulsonix, and run the Design Rule Checker on it. It showed some placement errors:

DRC Errors Report
-----------------

Report Written : 10/01/2009 05:05:40
Design Path : C:\Documents and Settings\User\Desktop\Sub_Amp_Board\Board.pcb
Design Title :
Created : 10/01/2009 04:53:59
Last Saved : 10/01/2009 04:56:53
Editing Time : 11 min

Board to Pad Error (B-P) Between (2.2- 0.0) and (2.2- 0.0+). Layer 'Top'. Required 0.1- Actual 0.0+.
Board to Pad Error (B-P) Between (0.0 1.4-) and (0.0+ 1.4-). Layer '<Through Board>'. Required 0.1- Actual 0.0+.
Board to Pad Error (B-P) Between (2.4- 1.4-) and (2.4- 1.4-). Layer '<Through Board>'. Required 0.1- Actual 0.0+.
Component to Component Error (Cm-Cm) Between (0.4 0.2) and (0.9+ 0.3+). Layer 'Top'. Required 0.0 Actual 0.0.
Component to Component Error (Cm-Cm) Between (1.5- 1.3-) and (1.6- 0.9+). Layer 'Top'. Required 0.0 Actual 0.0.
Board to Component Error (B-Cm) At (1.4- 0.2). Layer 'Top'.
Board to Component Error (B-Cm) At (1.8 0.2). Layer 'Top'.
Component to Component Error (Cm-Cm) Between (0.9+ 0.3+) and (1.3- 0.7-). Layer 'Top'. Required 0.0 Actual 0.0.
Board to Component Error (B-Cm) At (0.4 1.5-). Layer 'Top'.
Board to Component Error (B-Cm) At (1.2 1.5-). Layer 'Top'.
Board to Component Error (B-Cm) At (2.0 1.5-). Layer 'Top'.

Total:
5 Board to Component Error (B-Cm)
3 Board to Pad Error (B-P)
3 Component to Component Error (Cm-Cm)


Number of errors found : 11

The following rules were not checked:
All On Grid Rules
All Keep In/Out Rules
All Manufacturing Rules
All Net Rules

All acceptance rules were checked.

No net class spacing rules defined.

No net class pair rules defined.


---------------- End Of Report ----------------

The board-component errors probably don't matter, the others probably do. They should have been flagged by Eagle.


Leon

[bigglez]

Pulsonix starts at about 2,000 GBP, IIRC
Electra starts at $645

That's great! The OP who modded a working design to
save some cost on BatchPCB will no doubt want to
start over with your software suggestions.

Let's see, BatchPCB fees are:
$10 setup fee (incorporated into the shipping fees), 2 layer - $2.50/sq. inch 4 layer - $8.00.
How long will it take to break even?

It's good value, as designs can typically be completed in a fraction of the time it takes with Eagle.

How fast? I'm wondering if labour costs savings will
close the deal on your new software tools?

Even at 50 USD/hr net (not bad for a silicon valley
engineer with five plus years of experience), we'd
need to save about twenty hours.

Can your software be mastered from cold in twenty
hours?
(I know that it took me two hundred hours to get
anything out of EAGLE and I'm just under average IQ).

It's far better than the Eagle autorouter, typically routing to 100% completion even on complex boards.

Amazing, I'm very impressed. In earlier posts you
said:

(a) you'd only used EAGLE once and resorted to
doing your day-job work at home on the Polsonix
software, because you could get EAGLE to work for
your needs.
and

(b) you've never used BatchPCB.

Please read this post as it is written. I mean you
no harm or insult, but please consider staying away
from the EAGLE users that don't want to hear your
endless matra about how bad it is as a product.

Before we know it these hobbyists will start to feel
you're so superior and they're so wrong, they're stop
coming to this kewl place to share their work and ideas.

Thanks In Advance (and Belated Happy New Year to you).

[leon_heller]

Pulsonix starts at about 2,000 GBP, IIRC
Electra starts at $645

That's great! The OP who modded a working design to
save some cost on BatchPCB will no doubt want to
start over with your software suggestions.

Let's see, BatchPCB fees are:
$10 setup fee (incorporated into the shipping fees), 2 layer - $2.50/sq. inch 4 layer - $8.00.
How long will it take to break even?

It's good value, as designs can typically be completed in a fraction of the time it takes with Eagle.

How fast? I'm wondering if labour costs savings will
close the deal on your new software tools?

Even at 50 USD/hr net (not bad for a silicon valley
engineer with five plus years of experience), we'd
need to save about twenty hours.

Can your software be mastered from cold in twenty
hours?
(I know that it took me two hundred hours to get
anything out of EAGLE and I'm just under average IQ).

It's far better than the Eagle autorouter, typically routing to 100% completion even on complex boards.

Amazing, I'm very impressed. In earlier posts you
said:

(a) you'd only used EAGLE once and resorted to
doing your day-job work at home on the Polsonix
software, because you could get EAGLE to work for
your needs.
and

(b) you've never used BatchPCB.

Please read this post as it is written. I mean you
no harm or insult, but please consider staying away
from the EAGLE users that don't want to hear your
endless matra about how bad it is as a product.

Before we know it these hobbyists will start to feel
you're so superior and they're so wrong, they're stop
coming to this kewl place to share their work and ideas.

Thanks In Advance (and Belated Happy New Year to you).

I don't think I mentioned Pulsonix until you asked me what software I would recommend! The OP said that he'd autorouted his PCB, and I merely pointed out that autorouting that type of PCB was a waste of time, even with a good autorouter:

A good autorouter wouldn't work very well on a board like that, you should be routing it manually. Your use of the (rather poor) Eagle autorouter explains many of the problems with your layout.

Pulsonix users are typically productive within a few hours of first using the software, but they are usually experienced PCB designers already. I wouldn't recommend it to most hobbyists, as it's a full professional package with far more features than they will ever use, like matched length pairs and embedded components. Pulsonix does a good job of importing Eagle designs and libraries, and I have helped a couple of people complete their designs by importing them into Pulsonix. A good alternative to Eagle for hobbyists and educational users is Easy-PC, it's cheaper and much easier to use. I used it for over 20 years.

I don't remember saying that I used Pulsonix at home for my day-job. I think I said that I got permission from management to use my own copy of Pulsonix at work, because all the extra operations needed with Eagle were aggravating my RSI. A colleague of mine that knew Eagle well spent two weeks designing a PCB with it that I could have done in a couple of days with Pulsonix. Even with an employment cost of $100 an hour (it would actually have been much higher), the cost of the time saved on that one job (I make it $6,400) would have paid for a Pulsonix seat.

A Happy New Year to you as well!

Leon

[leon_heller]

I've just checked the component placements against the schematic, and there are several problems. Here is an example:



You should see that several highlighted parts that should be associated with U3 are in completely different locations. There are similar problems with U1 and U2. The SM capacitors don't matter in an electrical sense, but it will make it difficult to follow the circuit when debugging.

A useful technique when designing this sort of board is to concentrate on one of the amplifiers first, get an optimum layout for it, and then use an identical layout for the other amplifiers.

I noticed other problems with component orientation. You should be consistent and orientate all the capacitors, for instance, the same way, as I have done. It makes construction much easier, and you are less likely to make mistakes when assembling the board.

Leon

[FartingMonkey92]

"A useful technique when designing this sort of board is to concentrate on one of the amplifiers first, get an optimum layout for it, and then use an identical layout for the other amplifiers."

Yup, it looks like the OP on the diyAudio Forum used that same block layout technique for his boards...

[leon_heller]

It looks a lot more professional, as well as minimising any problems with stability. It can even be worth prototyping a single stage first, and testing it, before designing the whole system.

This is the sort of layout that I'd use for each amp:



I created a "tight group" of the parts for that amp in the schematic. This grouped the parts in the PCB, making it easy to identify them. Eagle probably has something similar.

Leon

[bigglez]

I don't think I mentioned Pulsonix until you asked me what software I would recommend!

Your use of the (rather poor) Eagle autorouter explains many of the problems with your layout.

Exactly my point, Leon. You have railroaded this thread to
promote a product that is not appropriate for the OP, or
many of us that do similar projects as a hobby.

You have even given your own data to show your product is
superior in every regard, yet much more costly.

Here's the bare facts from the OP:
(1) Layout was attempted in EAGLE, a hobby product
(2) This was done to reduce the one-off PCB expense
(3) The OP only admitted the design was copied
form another source when challenged by another poster.
(4) The OP doesn't understand ohms law, and is
struggling with the concept of adequate conductor
width and parts placement. EAGLE can solve all these
issues with a bit of coaching.

Here's the result:
(1) If you had checked your ego at the door, quit
the sales pitch for Pulsonix, and accepted the OP
was going to use EAGLE, you would have had a
good opportunity to address their immediate needs.
(Basic electronic circuit layout, and good practices
for high power audio amplifier design).
(2) I baited you into pitching Pulsonix, knowing it would
do nothing for the OP. (Who hopefully has not left us).
(3) You don't seem to connect the dots from the OP's
needs and your fascination with a software tool
well beyond the average hobbyist.
(4) Even if Pulsonix "made toast and did the laundry",
it's not a good fit for the visitors of this forum.

We appear to be going over old ground. I'm
wondering why you have to trash the more popular
PCB tool at every chance?

[leon_heller]

I think this is getting close to an optimum placement:



The inputs and outputs are on opposite sides of the board, and all the parts for each of the amplifiers are correctly grouped together matching the schematic. Lining things up will make each amp stage identical.

Here is a better image (after a bit of tidying up):

http://www.leonheller.com/Designs/amp4.gif

Constructive criticism welcomed.

Leon

[SpikedCola]

Exactly my point, Leon. You have railroaded this thread to
promote a product that is not appropriate for the OP, or
many of us that do similar projects as a hobby.

You have even given your own data to show your product is
superior in every regard, yet much more costly.
I personally dont mind - while he's giving me the option of another product, I dont have that kind of money just kicking around (nor will I for awhile), but it doesnt offend me that he suggested another tool

Here's the bare facts from the OP:
(1) Layout was attempted in EAGLE, a hobby product
Right
(2) This was done to reduce the one-off PCB expense
Yes and no. It would reduce the cost of this PCB, but I would also like to learn how to use Eagle for future use
(3) The OP only admitted the design was copied
form another source when challenged by another poster.
True, however I never claimed to have designed the circuit - in fact, I used a previously designed and tested circuit because I know that it will do what I want, and it has been tested (this saves me having to troubleshoot schematic errors and just leaves me with design errors )
(4) The OP doesn't understand ohms law, and is
struggling with the concept of adequate conductor
width and parts placement. EAGLE can solve all these
issues with a bit of coaching.
V=IR Im very familiar with Ohm's Law, and just finished my first of eight trimesters in my Electrical Engineering Tech Bachelor's program. My issue lies not in my lack of understanding of electronics in general, rather, in not knowing how to use Eagle. Rather than making large traces and doing a ground pour right off the bat and things like that, I would first like to become comfortable with the program and doing basic layout first. Im starting to think that this project has become a bit over my head as a beginner project - perhaps I should have started with a board that used a single LM3886 and progressed from there

Here's the result:
(1) If you had checked your ego at the door, quit
the sales pitch for Pulsonix, and accepted the OP
was going to use EAGLE, you would have had a
good opportunity to address their immediate needs.
(Basic electronic circuit layout, and good practices
for high power audio amplifier design).
(2) I baited you into pitching Pulsonix, knowing it would
do nothing for the OP. (Who hopefully has not left us).
I have done nothing of the sort! Actually, Im on the last day of my cruise, and internet is 75 cents per minute from the ship - that should explain my less-than-frequent posts
(3) You don't seem to connect the dots from the OP's
needs and your fascination with a software tool
well beyond the average hobbyist.
(4) Even if Pulsonix "made toast and did the laundry",
it's not a good fit for the visitors of this forum.

We appear to be going over old ground. I'm
wondering why you have to trash the more popular
PCB tool at every chance?
Again, not trying to defend leon, nor bash you, but it sounds to me like he was simply saying that Eagle isnt the best tool to use to autoroute my board at this time (however, it is all I can afford, so I plan to stick with it )

[leon_heller]

Actually, I was advising against using any autorouter on a board like that, it just won't do a good job. Analogue circuits like that should always be routed manually. Autorouters can do a good job, but they are almost exclusively used on digital circuits.

A board like that is a bit ambitious if you haven't done much PCB design, but it isn't out of the question. Your suggestion of starting with a single amp is a good one, it'll reduce the complexity and you'll have something that will have a good chance of working straight off. You can always make three of them and connect them together for testing, before you go ahead with the full PCB.

Leon