On Sun, 21 Mar 1999 21:32:48 -0800 Vic Rosenthal <rakefet@rakefet.com>
writes:
>
>OK, I'm planning the 3000v supply for my 2 x 3-500Z amplifier. I am
>going to
>use a FW doubler, like the SB-220, with a string of 8 capacitors.
>Looking at
>the Mouser catalog, they have
>
>Mallory CGS, 210 mf 450v, 85c $93.60 for 8
Take a look at what the big boys use, not one -off ham crap.
Even MFJ uses the CGS style caps. Does that sorta tell you something??
>CDE 380LX, 220 mf 450v, 85c $57.68 " "
>CDE 381LX, 220 mf 450v, 105c $78.16 " "
I have had no failures with the 381LX in SB-220 level amps. I have not
tried them in something with handles.
>
>There are also the All Electronics capacitors mentioned here before.
>I haven't
>called them to find out if they are still available, but these were
>270 mf /
>450v 85c, and were reported to be selling for $20 for all 8!
I suggested weeks ago...buy a bunch and test them on the bench in the ckt
you want to use. If they do not show a huge temp increase at 800ma key
down for say 30 minutes they are OK.
>
>Also, Harbach has a module containing 8 210/450 capacitors (I don't
>know what
>kind) for $115. It includes the mounting plates (easy to make) and
>the bleeders
>(pretty cheap). However, he matches the capacity within 1-1/2%.
Harbach does that in order to maintain long term reliability with a high
value equalizing resistor. If you start off with a very close tolerance,
it should hold over temp and time. Cheap caps are known for value drift
with temp.
>
>I am *very* tempted to get the All Electronics capacitors, if they
>are
>available. But I'm wondering if matching the capacities is a good
>idea? I
>could buy a few extra of the All Electronics caps in order to get
>them
>reasonablely close. But... it's often true that one gets what one
>pays for.
>
>Comments?
Play cheap or play smart, its ur choice. Sometimes both can coincide if u
know what you are doing.
73 Carl KM1H
>73,
>Vic, K2VCO
>Fresno CA
>
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>
>
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