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quadtech 4th March 2008 06:47 PM

chipamp PCB files
It would be good to have one thread as a repository for
all the free PCB chipamp designs.
Specifically, I am looking for a nice single sided lm3886 layout suitable for
toner transfer. And a nice Power Supply board too.
In addition to pdf of copper/silks, it would be great to make the CAD files available too.

The ones I found -


(not sure if this is free)


Minion 4th March 2008 07:44 PM

The LM3886 Circuit is so simple there is no reason why you can"t just design your own PCB ,Even if you have never designed a PCB before it should still not be very hard ,There are usualy less than a dozzen components for a simple Chip amp ,and even less components for the power supply ,That might be the reason why there are so many chip amp builders but so few PCB designs out there as anyone should be able to design a Chipamp PCB ,I usually build my Chipamp and the Power supply on the same PCB which avoids there being a lot of Off board wireing and less chance of grounding problems.....


gootee 4th March 2008 10:42 PM

Hi quadtech,

That might be a good idea.

But I would not limit it to single-sided. The toner transfer method is well-suited to easily making two-sided boards, especially for such relatively-simple layouts.

I have described one easy way to get good alignment between the two sides, on my toner-transfer PCB-making webpage, at ("As seen on TV" :-).

A two-sided pcboard would be able to have a better layout than a single-sided one. Not only could it possibly be smaller, it could also be electronically better-performing, since you could do things like run signal and power traces that have their return paths directly opposite them on the other side of the board, for minimum 'enclosed loop area', for example. Or, you could use one whole side for ground plane(s). At the least, your layout options would be much more flexible, since traces could then cross each other, by having one of them on the other side of the board.

I'd actually like to see someone design a MULTI-layer PCB layout for a chipamp (i.e. >= 3 layers), that could be made at home, so that at least a 'real' groundplane layer could be available, while still leaving at least two layers for power and amp circuits. I might have to finally try that, myself.

The idea would be to add at least a third layer to a two-sided board, by using an additional single-sided board (or maybe even by using three single-sided boards, I suppose).

The boards would be stacked on each other; probably glued together. To access an 'inner' layer, for soldering, you would just drill a large-enough hole in the board that was covering it, wherever needed, before assembly began.

PCB layout software would make it relatively easy to design like that, once a person got accustomed to adding access holes for 'buried' pads and vias, etc. For such simple types of layouts (such as chipamps), even four or five layers, or more, should not be difficult, especially since each layer that was added should simplify some things on the other layers. I can even imagine wanting six layers, i.e. maybe with a topmost layer used only as a 'shielding plane'. PCB blanks are cheap. And they can be very thin.

Imagine what a chipamp PCB layout could look like, if there didn't have to be any traces for V+, PGnd, and V-, for example, and two complete layers were still available for everything else.

BWRX 4th March 2008 11:10 PM

There really isn't any need for more than 2 layers due to the simplicity of the basic chip amp circuits. Using one layer is actually easier with through hole parts since there is plenty of room to run multiple traces under parts. You can make a great layout with just 2 layers and surface mount parts. Using 2 layers and through hole parts is not as good because the through holes can break up the ground plane on a two layer board.

BWRX 5th March 2008 08:14 AM

2 Attachment(s)
Since everyone seems to be talking about the LM1875 lately, I just came up with a very compact layout for a simple circuit using the LM1875. Here's the thread:

rehanabid 6th March 2008 12:29 PM

2 Attachment(s)
here you go, its a single sided 3886 board designed in Protel DXP. Feel free to distribute, edit.

kalmara 10th March 2008 01:19 AM

2 Attachment(s)
Hello. I am practising my PCB Design skills and I wanted to ask you for comments and reccomendations about my STK4040 PCB layout...I haven't built it, and eventually will not build it, it's all about an educational purpose. (and maybe to help some people, who want to hear the sound of the STK :D )
Here it is. After a few comments on it, and then I will post the original PDF, for making the PCB by the laser toner method, mentioned a few posts above.

kalmara 10th March 2008 01:25 AM

2 Attachment(s)
Here's the schematic I used. Notice that the little more powerfull filtering resistors R8 and R9 are not marked on the circuit, but are thought about on the PCB. :D (same thing about the boucherout cell resistor)

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