filter caps for twin iron

[Tonegeek]

Can I use a cap rated at 450V for the main (first) filter cap? IIRC the plate V should be around 440 (1970 iron)

[Bob-I]

Can I use a cap rated at 450V for the main (first) filter cap? IIRC the plate V should be around 440 (1970 iron)

I wouldn't. On power up you'll see voltage far higher than that. If you've ever had a filter cap blow in your face, you wouldn't even question this. Very scary.

[butwhatif]

Filter caps scare me to death. I always wear glasses when working on these. I once had one blow in my face into a hundred pieces all over the shop-why it did not take my eyes out I owe thanks to God.

[glasman]

I wouldn't use a 450V there either, use two in series with equalizing resistors.

Actually the scariest cap in the power supply is the screen cap after the choke. Don't scrimp here at ALL. That cap will see upwards of 700volts when the standby switch is thrown due to the choke.

[Tonegeek]

OK, I will revisit my options. Would love to use the doghouse but safety, reliability come first. I am going old style on the PS for this amp so its a new experience for me as I usually do the precision PS. I might be drilling steel for some can caps on this one.

[Structo]

Actually the scariest cap in the power supply is the screen cap after the choke. Don't scrimp here at ALL. That cap will see upwards of 700volts when the standby switch is thrown due to the choke.

Is that true if you you have your first filter before the standby switch?
On the classic power supply (#124) the screen filter is a 20uF 500v cap.
Is that not rated high enough to handle the surge?

[67plexi]

Mallory TVA series are ok listed as 450v but are 525v @ 10%. pre formed.
I have rebuilt more fender power sections than I can count never had a come back with Mallory.