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-   -   Generic Amplifier PS Board (http://www.diyaudio.com/forums/power-supplies/50024-generic-amplifier-ps-board.html)

jackinnj 21st January 2005 01:29 PM

Generic Amplifier PS Board
 
Your input is requested -- I used some GE Inrush Current Limiters as I always blew the diodes:

http://www.tech-diy.com/generic_brid...wer_supply.htm
http://www.tech-diy.com/LM4780_Bridg...owersupply.jpg

richie00boy 21st January 2005 04:13 PM

Nice board. I'm surprised the diodes blew as they can take large peaks. Did you try limiting the primary of the transformer?

Are there any issues with just switching the live? I mean Class II rules or something that maybe state you need to isolate both? OK this is DIY, but it's always nice to try and meet the standards :)

What are all the little lines 'pointing' to all the components?

Why not try for terminal blocks for the transformer as well?

Maybe add some 'steering' cutouts around the big PSU cap centre part to prevent eddy currents.

jackinnj 21st January 2005 07:48 PM

Quote:

Originally posted by richie00boy
Nice board. I'm surprised the diodes blew as they can take large peaks. Did you try limiting the primary of the transformer?

Are there any issues with just switching the live? I mean Class II rules or something that maybe state you need to isolate both? OK this is DIY, but it's always nice to try and meet the standards :)

What are all the little lines 'pointing' to all the components?

Why not try for terminal blocks for the transformer as well?

Maybe add some 'steering' cutouts around the big PSU cap centre part to prevent eddy currents.

The "Lines" -- some of them are force vectors which point to where the PCB layout program wants the parts placed. I didn't bother to "deselect" them when I did the screenshot.

The lines on the Panasonic THA caps were to allow me to figure out where to mount the auxiliary pins on these caps -- it wasn't a standard package in Ultiboard. They are on a ray which is 30 degrees up from the chord which cuts through the center (is my geometric terminology correct) -- the THA caps have two extra pins for more mounting security (supposedly) but they really prevent you from putting the caps in backwards!

Good point about the eddy currents -- will have to put some "traces to nowhere" in there to avoid the groundplane.

The inrush limiters can just be jumpered.

chipco3434 22nd January 2005 01:47 AM

I built my first regulated supply last weekend, p2p. The top looks OK but the bottom is a nightmare and an embarassment. It does work, but... If I wanted to build a board from your image, where should I start.

I am confused by the positive and negative methods and the exposure methods and the letterset methods. Too many choices. I have read the catalogs and the threads. So a simple question, what will you be using to make these boards.

richie00boy 22nd January 2005 08:56 AM

You are aware that this board is not regulated? And some would say that there is far too much capacitance for an unregulated gainclone? :rolleyes:

To make this board you would need to get the copper side layout from jackinnj. Then you get some positive working photoresist board and expose the board through the layout printed on acetate. Copper will remain where the acetate was blacked out, one you etch it.

jackinnj 22nd January 2005 03:05 PM

you can use whatever capacitance suits your fancy -- that's why there are auxiliary VIAs for the ELKO30_R10-- I will be happy to share the bottom side layout -- i would suggest that anyone who wants one obtain a freeware Gerber viewer like PentaLogix ViewMate -- you can print from the gerber file onto a piece of acetate film (either positive or negative). Positive resist board isn't expensive, very easy to expose, develop and etch.

email me and I will send the gerber file in RS274X format.

I am going to try put the inrush current limiter on the primary side. those I am using have a cold resistance of 2.5 ohms, and a hot resistance of less than 60 milliohms. I will also remove the connectors for fusing and switching -- it will save some space on the board -- and these connections don't have to be on the board anyway.

later today -- we are going to have a blizzard in NJ.

jackinnj 22nd January 2005 04:58 PM

placed an inrush limiter on the primary side -- left the other two in place, they can be jumpered.

cut out some of the ground plane beneath the filter caps, removed some of the islands.

http://www.tech-diy.com/generic_powersupply.jpg

jackinnj 3rd March 2005 11:53 PM

ok, this is how it looks, and it works great!
http://tech-diy.com/LM4780_Bridged/power_supply.jpg


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