Pavel Dudek's (Upupa Epops) LM4780 amp

Pavel Dudek's LM4780 amp

Pavel, your schematics has been downloaded 220 times. :up: EDIT: 9191 times 2004-09-20!

From that I can see a lot of curiosity. Several of us have stated that this design is a case of good solid engineering. For instance the Zobel network and output filter are put into focus. Safety is also at top priority even though it may not be totally necessary due to all internal protection of the LM4780.

Schematics can be found here
 
Thank you guys

I like very much precision work ( when I see motors from Mascom, my soul is singing :eek:) ). I mean, that good designed PCB is base of well working machine and when is it at this time nice too, your enjoy will be more than twice . :) Work on good designed PCB spend only little bit more time then work on worse one. ;) Little joke : devices get to know it and theirs reward is adequate - good function :clown: . Do you can to know my design philosophy, not only PCB's ?
 
mandat said:
Have a look at PCBs layout and the way of elements arrangement.
I use this arrangement (parts in a row) only when it's suitable, otherwise I place the parts where I think they should be. If the pcb would be manufactured it can be an advantage of parts in a row especially if you have pick and place machines. But over all I like Pavel's work. It shows that he has done this before.
 
peranders said:
Did you notice the absence of esoteric parts. This can't be high-end. :no: In fact, it must be rubbish. :nod:

Peter Daniel said:

I'm not sure what some of you mean by those comments, but Pavel's board reminds me very much of a board I made 10 years ago. It was very precise and without any exotic components;)

http://www.diyaudio.com/forums/attachment.php?s=&postid=411988
This is infact a rumour, my statement. I have heard it rather often.

Another rumour is " few parts are good, many parts are bad". The persons that repeat this doesn't know that a LM3886 is not one part. It is made of hundreds of parts....

My statement is: It's good if it's proven to be good. Period. 5 parts, 50 parts, 1000 parts I don't care.
 
More or less

When you look at recomended connection in datasheet, you will realy see there only a few devices and most of DIYers do it like this. But you must realize, that it is only simplest connection for quick testing. My connection is similar, but I had try it optimalise for lower noise and for low distortion, what signify, that Rg in both inputs must be approximately the same. If you can low current noise, you must to use higher value of resistors ( in input and in feedback ). For low voltage noise you must to use on the contrary lowest values. This seemingly opposite demand you can easy solve by separating DC and AC part of feedback only by one capacitor. Low value resistors in feedback have understandable higher power dissipation , so I get there three in parallel, 'cos overdimensioned value is good for lower thermal distortion. I know Vishay's bulk metal or Caddock resistors with low themal coeficient for space and military using, but this amp will be made by DIYers, not by Hughes Aicraft Company :cool:. This parts isn't easy to get and they are very expensive. I'm using parallel connection of resistors many years, 'cos they have more lower price and much more better reliability than power ones, they have more accuracy and they are easy to get all around the world. Which cost only one Caddock ? Which cost 83 pcs of 0207 resistors us, which is used here ? The same. Most of DIYers use this LM's without any protection, 'cos they think, that they have 100 % reliability, but it have only God's work ;) . What cost this protection, used here ? Only about three euro, price of two hamburger. Can you explaing more ?
 
Re: More or less

Upupa Epops said:
Can you explaing more ?
Probably :nod:

Your considerations aren't exactly at top priorty at most DIY'ers. I see nothing wrong in using exotic parts as long as you have good motives for it. Many, many times it's all about the coolness factor :cool: ... sometimes it can be other reasons.

If I think it's cool with Electronic Concept caps (the best in the world?) I would make room for these but also add holes for plain caps, just not to make the pcb hard to build in some parts of the world.

When I think about, nearly 1000 downloads in a few days, this clearly shows that you have a silent fan club. I think you should make at the pcb's available. :nod:
 
Motives

to Per - Anders : Yes, when I will know, that some part is necessary for best result what I need, I will use it and I will not thinking about, that other ones are are enough too - best is best and have not two alternatives :cool: . By the way, is possible use in this connection the best Vishay's bulk metal resistors ( they have small ones too ), but I think, that result will be not adequate to the price ;) .