LM3886 Amplifier Board

Community PCB Design
21

bigglez:

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 ‘’. Required 0.1- Actual 0.0+.

Board to Pad Error (B-P) Between (2.4- 1.4-) and (2.4- 1.4-). Layer ‘’. 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

22

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?

leon_heller:
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).

leon_heller:
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).

23

bigglez:

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?

leon_heller:
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).

leon_heller:
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

24

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

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

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

25

leon_heller:
“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…

26

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:

http://www.leonheller.com/Designs/amp2.gif

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

27

leon_heller:
I don’t think I mentioned Pulsonix until you asked me what software I would recommend!

leon_heller:
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?

28

I think this is getting close to an optimum placement:

http://www.leonheller.com/Designs/amp3.gif

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

29

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! :slight_smile: 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 :wink:

(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 ;))

30

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

31

SpikedCola:
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

Just be aware that most of the ‘success’ of that

circuit is the correct PCB layout. You came here asking:

SpikedCola:
this is the first thing I have ever designed/created in Eagle…

If you have any comments, suggestions, etc, please let me know!

You gave the impression that you had created this PCB,

and intended to fab and build it.

SpikedCola:
V=IR Im very familiar with Ohm’s Law

Then why run amperes of current through 25mil pin headers?

Also, why run inputs and outputs from a high gain (26dB) amplifier

next to each other? This has nothing to do with EAGLE.

You are not at a point to understand that such a circuit is doomed.

This has nothing to do with EAGLE.

SpikedCola:
I have done nothing of the sort! :slight_smile: Actually, Im on the last day of my cruise.

Fine. I was addressing leon_heller. His passionate

discussion of his favourite PCB software would scare

away anyone!

SpikedCola:
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

Do some homework. Use the search on this forum to find

"eagle’ and ‘leon_heller’. leon_heller jumps on most PCB newbies to

pitch his bloatware. EAGLE is not easy to learn, but has quite

a good price/performance for hobby needs.

You are one of several new members that have brought a

specific EAGLE problem here, and been told by leon_heller

you are wrong to use EAGLE. (But leon_heller will import your

EAGLE work into another tool and lecture you on your errors!).

By baiting leon_heller we see this behaviour in a better light.

BTW, leon_heller is compensated by the other tool’s publisher.

I’ve purchased my own copy of EAGLE.

32

I don’t get any money from Pulsonix, I get a license free in return for beta testing and consultancy.

As I said previously, there are more suitable programs than Pulsonix for hobbyists. Eagle will get the job done, but there are better programs around and some of them are cheaper.

I think that my component placement will solve most of the problems with the original layout, it shouldn’t be difficult to achieve something similar with Eagle. Perhaps someone else should help the OP with an example done with Eagle. Is Bigglez up for it?

I’ve used these two-part connectors on high-power amplifiers:

http://www.rapidonline.com/Cables-Conne … ocks/74998

Leon

33

Bigglez:
BTW, leon_heller is compensated by the other tool’s publisher.

leon_heller:
I don’t get any money from Pulsonix, I get a license free in return for beta testing and consultancy.

Confirming what I said. You don't need cash money to

have a conflict of interest. You are an official spokesperson

for that product. AFAIK, you also run their third-party

support group on-line somewhere, right?

34

leon_heller:
Perhaps someone else should help the OP with an example done with Eagle. Is Bigglez up for it?

The project has already been done and tested. See

the earlier link. Anyone interested in a 150Watt audio

power amp can download the Gerbers and BOM.

35

leon_heller:
I’ve used these two-part connectors on high-power amplifiers:

…

Leon

In the broadcast and recording studios these

are called [‘Phoenix Connectors’.

An ideal but costly alternative to screw terminals.](http://tinyurl.com/9mmnnd)

36

bigglez:

Bigglez:
BTW, leon_heller is compensated by the other tool’s publisher.

leon_heller:
I don’t get any money from Pulsonix, I get a license free in return for beta testing and consultancy.

Confirming what I said. You don't need cash money to

have a conflict of interest. You are an official spokesperson

for that product. AFAIK, you also run their third-party

support group on-line somewhere, right?

I don’t see a conflict of interest, I use the product, like it and don’t mind mentioning it. I’m not an official spokesperson for Pulsonix. I do run the Yahoo support group, which is independent of Pulsonix.

Leon

37

bigglez:

leon_heller:
I’ve used these two-part connectors on high-power amplifiers:

…

Leon

In the broadcast and recording studios these

are called [‘Phoenix Connectors’.

An ideal but costly alternative to screw terminals.[/quote]

They are a fraction of that price here in the UK. It must be because they are made here.

Leon](http://tinyurl.com/9mmnnd)

38

bigglez:

leon_heller:
Perhaps someone else should help the OP with an example done with Eagle. Is Bigglez up for it?

The project has already been done and tested. See

the earlier link. Anyone interested in a 150Watt audio

power amp can download the Gerbers and BOM.

But the OP has already stated that he wants to design his own PCB as a learning experience. He obviously needs some help, which I didn’t mind giving. Of course, component placement is the easy part. The layout will be quite challenging, given the requirements in the data sheet.

Leon

39

leon_heller:
I don’t see a conflict of interest, I use the product, like it and don’t mind mentioning it.

Mention? Now that's an understatement!

leon_heller:
I’m not an official spokesperson for Pulsonix. I do run the Yahoo support group, which is independent of Pulsonix.

So by definition you're not impartial or even fair.

[conflict of interest](Conflict of interest - Wikipedia)

40

leon_heller:
I don’t see a conflict of interest, I use the product, like it and don’t mind mentioning it.

You don't mind **mentioning EAGLE** either:

leon_heller Fri Jan 09, 2009 9:40 am:
Your use of the (rather poor) Eagle autorouter explains many of the problems with your layout.

leon_heller Fri Jan 09, 2009 2:29 pm:
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.

leon_heller Posted: Fri Jan 09, 2009 9:02 pm:
There are much better tools, of course, like the Pulsonix software I use. Pulsonix uses the Electra autorouter, which is available for Eagle.

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.

leon_heller Posted: Sat Jan 10, 2009 10:44 am:
Ypu might want to look at Easy-PC:

…

I used it for over 20 years, and was one of their first customers.

It’s much easier to use than Eagle, and is more affordable for hobbyists and students. The standard autorouter is better than the Eagle one, and you can upgrade to the excellent Pro-Router quite cheaply (it’s actually Electra). It’ll import Eagle designs and libraries.

leon_heller Posted: Tue Jan 06, 2009 11:37 am:
I don’t use Eagle, but that sounds like the well-known feature/bug with the grid; pins need to be on the grid otherwise you can’t connect to them. They really should have fixed it by now. You probably need to edit the schematic symbol.

leon_heller Posted: Fri Oct 03, 2008 2:14 pm:
Easy-PC is much easier to use than Eagle, and costs about the same:

leon_heller Posted: Sat Oct 04, 2008 1:01 am:

Stevech:

leon_heller:
Easy-PC is much easier to use than Eagle, and costs about the same:

rather pricey for the hobbyist at USD$477
That's actually £477 GBP. It starts at £247 GBP.

Eagle costs about $1,000 for an equivalent version to the unlimited Easy-PC version.

Easy-PC also has an excellent autorouter and support is very good.

leon_heller Posted: Sat Oct 04, 2008 2:41 am:
No, I just like the products. I Used Easy-PC for over 20 years until Pulsonix came along.

Both offer email and telephone support, as well as support via forums.

Easy-PC was developed specifically for the hobbyist and educational market, although it is also used by a lot of professionals.

I get Pulsonix free in return for beta-testing and a bit of consultancy.

The Pulsonix router did it in just over two minutes. It’s done quite a good job. Easy-PC uses the same router.

Both Easy-PC and Pulsonix can import Eagle libraries, schematics and PCBs. I’ve actually helped people who have been unable to finish their designs with Eagle by importing them into Pulsonix!

They tried to get me to use Eagle where I used to work. I refused, because it took about twice as many mouse and keyboard operations to complete a design as it did using my own copy of Pulsonix, and it was aggravating RSI which I suffer from occasionally. It also tended to crash on me, Eagle support didn’t even respond to my request for help.

leon_heller Posted: Sat Oct 04, 2008 9:53 am:
The OP asked for a good PCB package, so I suggested one. What’s wrong with that? If he’s used to Protel, he is much less likely to have problems if he moves to something that operates in a similar manner like Easy-PC than if he moves to Eagle.

For some amusement (or schadenfreude) I just had a look at the Cadsoft Eagle support forum: it’s full of tales of woe about crashes, slowness, and problems with the software. The Pulsonix and Easy-PC forums have very few, if any, posts like that.

leon_heller Posted: Sat Oct 04, 2008 3:12 pm:
I get Pulsonix free in return for beta-testing and a bit of consultancy.

The Pulsonix router did it in just over two minutes. It’s done quite a good job. Easy-PC uses the same router.

leon_heller Posted: Wed Aug 06, 2008 8:55 am:
I used EasyPC for about 25 years:

http://www.numberone.com

It’s about the same price as Eagle and is much easier to use.

leon_heller Posted: Mon Jun 16, 2008 11:04 am:
You should route critical nets like power and ground manually, even with good autorouters. The Eagle one is very poor.

leon_heller Posted: Sun Jun 08, 2008 1:26 pm:
It’s probably something to do with your Eagle settings. I don’t use it so I can’t help you.

leon_heller Posted: Thu Feb 28, 2008 2:53 am:
Pulsonix is far easier and faster to use than Eagle, and competes with more expensive packages like Altium Designer, PADS and OrCAD.

I actually compared Pulsonix and Eagle once, and found that equivalent operations were twice as fast with Pulsonix, primarily because of all the additional keystrokes and mouse clicks required with Eagle. Where I used to work a colleague of mine who knew Eagle very well took two weeks over a PCB that I could have done in a couple of days with Pulsonix.

leon_heller Posted: Wed Jun 25, 2008 10:32 am:
It’s a pity I can’t export footprints from Pulsonix, although it can import designs, footprints etc. from Eagle. I might be able to sell them to lazy Eagle users.

As a lazy EAGLE user I think leon_heller has demonstrated

that he’s far from a neutral opinion on PCB layout tools.

Caveat Emptor!