Question about ST-35 filter supply...

[LowRedMoon]

I'm buzzing around, checking out EL84 amplifier schematics (a current fixation of mine) and would like to ask a question about the version of the ST-35 that is featured on this forum.
I'm very curious to know why there is a 100uF cap between the EL84 plate supply and the driver/phase inverter supply that is not connected to a stage in the audio circuit. Does this improve filtering to the driver/P.I. section? Also, would it take a very long time for the section in question to discharge once the amp is off without a load or bleeder attached?

Thank you for humoring me.

Glad to see that attention is still paid to the ST-35.

Be well,

Adam

[TomMcNally]

Hi Adam -

Can you be specific as to which capacitor in which schematic
you are referring to ? (by C- number) The diytube ST-35
doesn't have any 100 mfd caps ?

... tom

[LowRedMoon]

Sorry about that - my mistake.

I'm refering to c11, which is 120uF, not 100uF.

Adam

[TomMcNally]

C-11 is just additional filtering in an RC network ...
The more filtering the better ...
It would discharge back through R-32 the 3.3K dropping resistor to
the 300K bleeder (R-29) rather quickly.

Bleeder resistors in any high voltage circuit are no
substitute for common sense and respect of electricity.
Always discharge any capacitor to ground before
touching it.

[LowRedMoon]

Thanks for the reply.

Bleeder resistors in any high voltage circuit are no
substitute for common sense and respect of electricity.
Always discharge any capacitor to ground before
touching it.

And safety mantras are no substitue for the severly painful "all of the atoms in my arm feel like they've instantaneously moved twelve inches upward" feeling of accidentally bumping the HV terminal of the bridge rectifier that's connected to the 100uF input cap of an old Grundig radio that's been powered off.
Believe me, I know.

Thanks,

Adam