I had already fattened the large capacitors' pads to 124 mil and used 40 mil tracks at the power amp's supply! But I will follow your advice for the rest of the components as well. It is kind of annoying that you have to manually modify each components pad dimension, but once I make a full modified library, it wont be necessary again.

Thank you very much for the advice.
Offtopic question: Do you think it's necessarry to use these sizes for pedals also? I'm currently using 24 mil tracks, 50 mil pads, and 22 mil clearence.

I think it's time to report my progress so far; I have made a layout for the power supply based on the schematic i have previously posted.
Below are two versions, the differences between the two are the ground and the pilot light. The first version has a common ground and a low voltage pilot light. The second version has seperate grounds for the power amp's and the preamp's power supply (which will eventually meet at some point I guess) and a no pilot light on the board. I think I'll go with the 2nd version and use a 230V pilot light but there is still though some studying to be done on grounding before the actual realization.

So here it is...

Note (Sept 12 2011) that after following J M Fahey's suggestions below, I edited the post leaving only one version which I think is best.

Quote from: J M Fahey on August 29, 2011, 05:02:41 PM
...old trusty DOS...

There are still peolple that use DOS? Now that's something worth an offtopic!
And I thought I was the only one who still plays Daggerfall!

Quote from: joecool85 on August 12, 2011, 08:21:36 AM
Looking forward to seeing your progress.  Are you making your own PCBs?

I haven't made any yet, but I will be making my own from now on. I'm currently designing the layouts to be trasfered. As soon as I get the hang of it, I will procced with this project. It may take some time though because spare time is limitied due to work and stuff. But, as I said on previous post, I will report with my progress ASAP.

Cheers!

Quote from: teemuk on August 11, 2011, 07:55:17 AM
Somekind of filtering in close vicinity of the regulator's input pin might be though, depending how long wiring there is from the main filter caps to the regulator.

Not long. They will be on the same board.

Ok, so I have a "good-to-go" on the power supply! I'll report back when it's done.
Thanks again!

So far I've made a schematic for the overall power supply of the amp.

On the AC side I placed a DPDT switch that connects the Live and Neutral wires from the wall and a fuse on the Live wire before the transformer.

On the DC side:
- I use a standard bridge rectifier to convert ACto DC.
- Optional 10nF caps across the pins of the rectifier. Are these necessary?
- 2x4700uF caps on each rail.
- A bleeder resistor placed between the rails. As for the value, I'm not sure yet, I just saw the particular value on tube amps. I'll propably change the value and place the pilot light there, too.
- C9-C12 were taken straight from the datasheet of the TDA2040.
- On the positive DC rail, past the large filter caps I placed 9V regulator taken straight from tonepad, to supply the preamp and any buffer I may need to place. Is C17 absolutely neccessary, or are C5 and C6 enough?

I hope I have the Caps' polarities correct.

I found a nice 12-0-12 toroidal transformer rated 80VA. I haven't bought it yet, maybe tomorrow I'll go and buy it. I hope it can be capable of powering a 2xTDA2040 amp with 2 preamps and a couple of buffers (although I don't think the preamp section will draw a significant amount of current). Also the store owner suggested using filter capacitors >=3300uF on each rail. I'll post a schematic with the power supply section when I finish it.

Edit: Thank you very much for the support!

Quote from: joecool85 on August 05, 2011, 08:05:24 AM
I personally wouldn't even build it with a 16 ohm load in mind, it just won't put out that much wattage.  Might be worth looking into a different power IC or a different speaker.

Some time in the future I'm planning on getting myself another one of those cabs. This way I can form a mini stack of total 8Ohm load.

Actually, i'm going to use it with a 16Ohm load. I have one cab with a 16 Ohm speaker, so I guess a TDA2040 will give around 8watt@16Ohm. Plz correct me if I'm wrong.

So if one chip draws 3.5A, for a bridged amp I'm gonna need a transformer of around 6 or 7 Amperes. I suspect it's gonna be quite bulky! It may not be THAT worth the effort, but I may go for it anyway.

Thanks a lot BTW! All that info have been really really helpful!  :tu:

Moving on with the theory before trying to build the amp, I believe I should use a 18-0-18 transformer, in order to provide the power amp with +-18VDC. If that is correct then my next concern is how much ampere-rating should the trasformer have (so I can order it from the local store). I don't know how much maximum current the TDA2040 draws, and I'm not sure where I can see it in the datasheet.
Does anyone know the maximum current draw of the TDA2040? Or to be more specific, two bridged Tda2040s powered by +-16 or 18 VDC, in order to provide 30W or so of output power?

I hope I'm not (that) tiresome, and please forgive my english if they are a bit lousy sometimes.

-Adam-

Thanks for the swift reply! After reading it, I took some time and looked at the power supply section of your book.
From what I understand in order to make a bipolar power supply, I have a number of options.
a)Use a center-tapped transformer and wire the center tap to ground.
b)Use a symmetrical dual transformer, which I don't think is quite neccessary in this case.
c)Use a transformer with single secondaries and make a virtual earth circuit.
The best option seems to be a)... right???

Hi everyone!

It's my first post here. I have been messing with electronics for almost a year now, made about half a dozen pedals, another half a dozen waiting on the shelf, and I also have an 18watter in progress.
Recenlty, the only amp I've been using is the Noisy Cricket (my first complete build), and I was amazed at how good a simple solid state amp can sound. So my interest turned to building a SS amp with enough power but still without the need for output transformer. The best option right now seems to be the TDA2040. Also I'm planning on putting a preamp such as the Umble plus an FX loop.

1) Can I use the schematic from general guitar gadgets for a bipolar power supply to power the amp?
If yes, I guess that the appropriate transformer would be one with 12V secondaries, and the regulators should be 7809 and 7909 so I can provide +9V and -9V?

2) If I want to make a complete amp with preamp and poweramp, which I can power straight from the wall, can I use an additional 7809 regulator with the appropriate additional capacitors and diode, to provide an extra power output of +9V to power the preamp from the same supply, or will I need an extra transformer to make a seperate supply?

3) Lastly, If I want to use two TDAs for a 30W amp how could I power it? The bipolar power supply schematic at GGG has an option of +-15V ouptut or 18V, whereas a 30W TDA amp needs +-16V according to the datasheet.

-Adam-