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Old 2nd March 2013, 06:14 AM   #1
Hikari1 is offline Hikari1  United States
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Default F5 increased capacitance

I am in the beginning stages of an F5 build, next up is power caps.

I have a 600va transformer, any harm in bumping the 8 x 15,000uf caps to say 8 x 22,000uf? the cost difference is not much and they will fit on the board. The caps I am looking at are Panasonic TSUP 35v.

ECO-S1VP223DA Panasonic Electronic Components | Mouser

Will the CL-60 thermistors still be enough or do I need to look at soft start? Planning on running a 35amp bridge.

Also, the Pass schematic specifies 25 volt caps. There's 24 volts on the rails. Wouldn't 35v be a better choice?
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Old 2nd March 2013, 08:42 AM   #2
Zen Mod is offline Zen Mod  Serbia
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with 18Vac secondaries , you'll have aroundish 22Vdc under load

if you are not sure how to maintain voltage under 25Vdc during setup procedure , then buy 35Vdc caps

22mF isn't critical ; I'm having 33mF-0R1-33mF on each rail in FW based sort of monoblock (common 800VA xformer , with 4x18Vac )
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Old 2nd March 2013, 10:48 AM   #3
WalterW is offline WalterW  Netherlands
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Hikari no problem at all, i used the exact same capacitors, see here:

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Old 2nd March 2013, 12:25 PM   #4
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You're better off with a softstart that bypasses the CL60 after some seconds.
Plenty of those can be found on ebay
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Old 2nd March 2013, 05:56 PM   #5
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ApexJr has these 33mF 50V caps for $4 each. Get some Teflon coated wire and some big rubber feet while you're ordering.

For soft start, next time I want to try something with an AC relay like 'Fig. 2' in the attached article.
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File Type: jpg Softstart1.jpg (330.9 KB, 361 views)
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Old 2nd March 2013, 06:02 PM   #6
Zen Mod is offline Zen Mod  Serbia
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CL60 alone is perfect
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Old 2nd March 2013, 06:44 PM   #7
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Quote:
Originally Posted by Zen Mod View Post
CL60 alone is perfect
For a normal amount of PS capacitance, I agree.
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Old 2nd March 2013, 07:34 PM   #8
Zen Mod is offline Zen Mod  Serbia
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it's covering fine 800VA Donut , 8x33mF , all that on 220Vac

4A fuse
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Old 2nd March 2013, 10:23 PM   #9
Hikari1 is offline Hikari1  United States
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Zen: That's good to know. I'd rather user the Cl-60 than a softstart board.

Apex Jr. looks like a great shop. I may order some wire from them. Don't know if I am ready to point to point a power supply yet though.

I know it's been done to death but you guys have any opinions on IRF vs Fairchild vs Toshiba outputs? It will be a standard F5, One pair N/P per channel.

I am leaning towards IRFs becasue they are easy to get. The Fairchilds seen to be unobtainium and the Toshibas scare me with the different pin out and possible resistor change needed.
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Old 2nd March 2013, 10:27 PM   #10
Zen Mod is offline Zen Mod  Serbia
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best thing after wheel is - soft start circuit but filled with series NTCs , instead of fixed resistors

that will give you really soft start

whatever - that's better in just one instance - behavior in case of mains blackout - when you'll need maybe every 10-th time to change fuse

which Toshibas exactly ?
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