[Amps] Acceptable ripple on high voltage plate power supply in tetrode amplifiers.

[Lukasz]

On Wed, 18 Dec 2024, 14:26 Ron W4BIN, <ka4inm at gmail.com> wrote:

   Łukasz SP4IT wrote:

> 2uF seems awfully small. From the calculations I did (200hz, 200mH
> inductance) it seems there will ve 300V of ripple at max current of 1A
> (10%!). Isn't that too much and how could the military transmitter work
> like this?

   I suspect the original circuit is a series resonate circuit at the
ripple frequency.


I'm not sure. This is the schematic:

https://ibb.co/KzmLW4C

The choke/inductor is next to R40 with (Russian letters) Dr2. The capacitor
C9 is external to the power supply at the bottom left. It it right next to
the resistive divider used to measure the high voltage (r39 and r48, r41
goes to the meter). The terminal 4 (bottom left) is the minus of HV DC, it
has the overcurrent protection with relay coil P7. And terminal 7 is also
HV DC minus, but with no overcurrent protect (used for the capacitor
minus).

I even recently procured a suitable Russian oil filled capacitor(as per the
manual) . It is the size of a brick and weights the same as one. It is 2uF
4kV.

With my DIY amp I used a bank of electrolytes. I had made few QSOs and all
correspondents said they could hear nothing unusual. So 16uF appears to be
enough.

73,
Łukasz - SP4IT