Lm4780 SS PCB

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I just had to knock this up for my own use as a single sided, dual mono board for home manufacture, but I thought I'd post it here just in case it's any use to anyone else. It's based loosely on the work of Brian GT and Peter Daniel, but I've added the soft start mute enable circuit shown in the datasheet. If anyone's interested, I'll post the Eagle files.
 

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I'll post the Eagle files for you all tomorrow, I'm not at home right now.

dfdye, the soft start works well, I used it because I will be using active crossovers and I didn't want any start up twinges in them getting through to the speakers. The power rails are laid out like that because I am using twin rectifiers, so the ground connections at the bottom are for connection purely the a star ground on the chassis.

Mmne, the schematic is virtually exactly the same as the datasheet, so if you download that you will have all the info you need. The PSU is eight MBR10100s in a split bridge configuration, and four 1000Uf Rubicon ZLs. It was one I made a while back, so I didn't do a PCB.
 
Looks very nice and simple.

I don't get why Upupa said the rail traces were too thin. They look to be at least 60 mils to me. Short 60mil traces won't drop much with 3A or so going through them.

Heh, I remember someone's GC using 10,000uF rail caps :)

Question: Isn't 4 X 1000uF of rail cap a bit on the low side for a 2 X 60W amplifier? It is so wierd that the same folks who use weeny PSU caps on their GC's turn to giant banks of PSU caps for their Aleph clones.
 
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My implementation will use the LMs for mid and treble, and an exixting mosfet amp for bass, so I'm not expecting huge demands on the chips, and the highs are better with lower capacitance in the rails. If you were using them full range, then you could usefully go up to about 10000uf per rail, bass would improve, but the top end suffers a little.
 
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Mine is designed for dual mono. It's that way, 'cos that's what I needed!

The schematic may look like Peter's, but has none of the optional other components for different configurations. You could bridge/parallel it if you wanted, but there are better PCB designs for that. Then again, you could just alter the Eagle files to do whatever you you wish. ;)

All the info on the muting is on the datasheet, you have read it, haven't you?
 
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My PCB was designed by me for a specific job. It was never supposed to be universal, and I just posted it here in case it was useful to anyone else. I have no intentions of spending more time changing it, but if anyone else wants to, then feel free. It would be a good learning experience.

I suppose that the mute circuit is just a voltage with a resistance (? ohm?)? and a switch?

As I said, download and read the LM4780 datasheet! ;)
 
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