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Old 13th November 2008, 08:05 PM   #221
Thomo is offline Thomo  United Kingdom
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Hi guys.

I've finally got around to working on that board!

I know that star grounding is a good idea, but is it critical in this application? I am trying to do a board layout which will enable C1 100nF to be a Mundorf Supreme or some other nice polypropylene cap. This is large though, and making things tricky to work around.

Cheers, Lee.
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Old 13th November 2008, 08:09 PM   #222
SimontY is offline SimontY  United Kingdom
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Quote:
Originally posted by Thomo
Hi guys.

I've finally got around to working on that board!

I know that star grounding is a good idea, but is it critical in this application? I am trying to do a board layout which will enable C1 100nF to be a Mundorf Supreme or some other nice polypropylene cap. This is large though, and making things tricky to work around.

Cheers, Lee.
What about the range down, it's much smaller isn't it? ZN?

Simon
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Old 13th November 2008, 08:45 PM   #223
Salas is online now Salas  Greece
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Quote:
Originally posted by Thomo
Hi guys.

I've finally got around to working on that board!

I know that star grounding is a good idea, but is it critical in this application? I am trying to do a board layout which will enable C1 100nF to be a Mundorf Supreme or some other nice polypropylene cap. This is large though, and making things tricky to work around.

Cheers, Lee.
Me I have used a U shaped peripheral copper wire busbar with the arm and RCAs grounded at its one end, and I have no ground loops at all. Star is theoretically better though.
The Supreme is the biggest one, its good to allow space, but if its really tricky, just make space for chunky radial ones or smaller axial like the Auricap. I use a Soviet radial Polystyrene that is very neutral and big enough but no monster.
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Old 13th November 2008, 08:51 PM   #224
Salas is online now Salas  Greece
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Quote:
Originally posted by cygnus x1
Hi Salas,
Thanks for the info. I'll wire one up and give it a try. I don't have the BC parts, but the PN2222a and PN2907a should come close enough. I'll stick with the IRFP9240, in the past when I've tried faster Mosfets, they oscilate. I'll let you know how it works out.
Good one, thanks! Keep us posted. For what kind of circuit are you going to use and test the shunt PSU?
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Old 14th November 2008, 09:48 AM   #225
Thomo is offline Thomo  United Kingdom
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Hi guys.

I managed to get this drawn up this morning. I haven't yet had chance to finalise it, or check for errors.

I just thought I'd show progress so far. Any suggestions welcome as always.

Regards, Lee.
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Old 14th November 2008, 10:07 AM   #226
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add elettric schema....
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Old 14th November 2008, 10:11 AM   #227
Thomo is offline Thomo  United Kingdom
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Schematic was posted here

Cheers, Lee.
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Old 14th November 2008, 10:17 AM   #228
SimontY is offline SimontY  United Kingdom
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Lee,

Perhaps he means add a power supply.

Simon
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Old 14th November 2008, 10:21 AM   #229
Thomo is offline Thomo  United Kingdom
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LOL. Oh yeah.

I was thinking of keeping the psu either on a separate board, or in a separate case.

I could add the regulator Salas posted, but I don't have the time to test if it works before implementing into the layout.

I have just double-checked my layout against the schematic and everything seems in order. (I think the fets are the correct way round, lol).

Regards, Lee.
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Old 14th November 2008, 10:25 AM   #230
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seems ok !
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