[Amps] Plate modulation from power supply ripple?

[Markku Oksanen]

Hi Gary, All
I was thinking about your statement and looking a typical tube anode characteristics (curves).If I read this correctly, change in plate voltage does cause a change in plate current.Is this not plate modulation?  I am not sure if the operating class changes this.Perhaps I need to simulate this too...
Thanks
MarkkuWW1C

> From: garyschafer at comcast.net
> To: ww1c at outlook.com; amps at contesting.com
> Subject: RE: [Amps] Plate modulation from power supply ripple?
> Date: Wed, 2 Oct 2013 12:36:06 -0500
> 
> You don't hear the ripple because it does not modulate the linear amplifier.
> If you were to run the amplifier in a non-linear mode such as class C then
> it would plate modulate it.
> 
> 73
> Gary  K4FMX
> 
> > -----Original Message-----
> > From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Markku
> > Oksanen
> > Sent: Wednesday, October 02, 2013 12:40 AM
> > To: amps at contesting.com
> > Subject: [Amps] Plate modulation from power supply ripple?
> > 
> > 
> > All
> > I was simulating (with LTspice) a three phase power supply where the
> > secondary is in star configuration with full wave rectification. You can
> > get also a second voltage from this by connecting to the center of the
> > star, this voltage is half of the full wave rectified voltage and is
> > only half wave rectified (per phase), 3 pulse in stead of 6 pulse for
> > the higher voltage.
> > It turns out that even relatively high value (tens of uF) filter
> > capacitors would leave some 10% of ripple on the lower voltage.  Now the
> > question is: How much plate modulation this make?  The ripple frequency
> > is 150 Hz and to me this looks like your regular high level, plate
> > modulated AM transmitter.  Why do we not hear this on a typical signal
> > if it is there?
> > 
> > MarkkuWW1C
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