Because if you make a large "SMD" pad, the solder connection between the wire and PCB has greater area than if wire is soldered at a hole through pad.....
Further more the "SMD" type pad better accepts all kind of wire sizes.....
Remember that this is not a "standard" commercial PSU, but has to adapt to all kind of wires at hand of fellowing diy'ers.
ACD said:So do I
Right now I'm trying to make the layout....
It's gonna be a quite large PCB though (as to the space reserved to CRC etc....)
Would the best layout be a long PCB suitet to be fitted a long the heat sinked sides of the cabinet ?
It will be quite biggish, in any case. What Dia do you have in mind for the 'lytic's? A Pansonic TSUP 33,000uF 50V is 35mm.. If you want to use 100V 'lytic's, maan......
The board size will be huge.
40mm is good enough for a large PSU. 10W resistors are not really needed. I think that several 3 watters in parrallel takes up less space? 5 pcs in parrallel is perfectly allright. The bleeder also only needs to be 3 watt's at eg 3.3K.ACD said:As stated the caps are 40mm in diameter
And the space for CRC has room for 10W several resistors
And the bleeder resistors are also 10W
Size of components are mentioned in the last schem I posted
(Maybe the solution is to make a three storage high amp with a view
Hi Jan.
You are doing well. I agree with Steenoe, caps up to 40mm dia will allow for a very stiff DC supply particularly if you choose to load all 4 of them per rail.
The fuseholder you specify is good as it allows 20mm and bigger fuselinks. I would still like to see these on AC and DC rails.
The CRC resistor only needs to be 3 watt in size but as Steenoe says allow for 5 of these. See Nelson Pass's PSU designs where he might use 5 off 1 ohm 3watt resistors in parallel to give 0.2 ohms at 15 watt capacity.
Also the bleeder resistor only needs to be 3 or 5 watt. Even with Steenoe's example of 3k3 resistor across a fairly high DC supply of 75 volts = 1.7 watts diss. Stand resistor 5mm clear of board and it will be OK.
Hope this helps.
Regards
Gary..
You are doing well. I agree with Steenoe, caps up to 40mm dia will allow for a very stiff DC supply particularly if you choose to load all 4 of them per rail.
The fuseholder you specify is good as it allows 20mm and bigger fuselinks. I would still like to see these on AC and DC rails.
The CRC resistor only needs to be 3 watt in size but as Steenoe says allow for 5 of these. See Nelson Pass's PSU designs where he might use 5 off 1 ohm 3watt resistors in parallel to give 0.2 ohms at 15 watt capacity.
Also the bleeder resistor only needs to be 3 or 5 watt. Even with Steenoe's example of 3k3 resistor across a fairly high DC supply of 75 volts = 1.7 watts diss. Stand resistor 5mm clear of board and it will be OK.
Hope this helps.
Regards
Gary..
Hi again Jan.
Forgot to comment on size/shape of PSU board.
I would be happy with the board long and narrow ,say 90mm or so wide to accomodate the 40mm caps and then however long it ends up to fit all other components.
I tend to build mono block power amps and always have plenty of room which is usually dependent on heatsink length especially for high bias class A designs.
Regards
Gary..
Forgot to comment on size/shape of PSU board.
I would be happy with the board long and narrow ,say 90mm or so wide to accomodate the 40mm caps and then however long it ends up to fit all other components.
I tend to build mono block power amps and always have plenty of room which is usually dependent on heatsink length especially for high bias class A designs.
Regards
Gary..
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