[Amps] Acceptable ripple on high voltage plate power supply intetrode amplifiers

Fri Dec 20 19:50:49 EST 2024

According to Pappenfus, Bruene and Schoenike in their 1964 textbook "SSB Principles and Circuits" the ripple modulation on SSB is typically 15-20 dB lower than the % ripple on the plate DC power for a linear RF amplifier using tetrode. Only during the peak power excursions where plate voltage gets close to screen voltage, and the tube deviates from constant current characteristics does ripple modulate the RF more directly. I am not sure how it translates to grounded grid triode operation. Of course, class C operation, such as for CW or AM, is directly modulated by power supply noise. 
73,
John
K5PRO

On Dec 19, 2024, 10:00 AM, at 10:00 AM, amps-request at contesting.com wrote:
>Send Amps mailing list submissions to
>	amps at contesting.com
>
>To subscribe or unsubscribe via the World Wide Web, visit
>	http://lists.contesting.com/mailman/listinfo/amps
>or, via email, send a message with subject or body 'help' to
>	amps-request at contesting.com
>
>You can reach the person managing the list at
>	amps-owner at contesting.com
>
>When replying, please edit your Subject line so it is more specific
>than "Re: Contents of Amps digest..."
>
>
>Today's Topics:
>
>   1. Re: Acceptable ripple on high voltage plate power supply in
>      tetrode amplifiers. (dj7ww at t-online.de)
>   2. Re: Acceptable ripple on high voltage plate power supply in
>      tetrode amplifiers. (Lukasz)
>   3. Mercado Libre Amplifiers, Transceivers, and More
>      (Juan Pablo Ravinale)
>
>
>----------------------------------------------------------------------
>
>Message: 1
>Date: Wed, 18 Dec 2024 19:59:59 +0100 (CET)
>From: "dj7ww at t-online.de" <dj7ww at t-online.de>
>To: Lukasz <sp4it.mail at gmail.com>, "ka4inm at gmail.com"
>	<ka4inm at gmail.com>
>Cc: "amps at contesting.com" <amps at contesting.com>
>Subject: Re: [Amps] Acceptable ripple on high voltage plate power
>	supply in tetrode amplifiers.
>Message-ID:
>	<1734548399222.1293455.43f118d79777b9935f2258c035245ab12025a4a4 at spica.telekom.de>
>	
>Content-Type: text/plain; charset="utf-8"
>
>I use 2?F and no choke with my 3-phase DB6  power supply and nobody
>hears any hum.
>
>Check with Dr.Alex if you need larger capacitors:
>http://www.ur4ll.net/#caps1
>
>73
>Peter, DJ7WW
>
>
>-----Original-Nachricht-----
>Betreff: Re: [Amps] Acceptable ripple on high voltage plate power
>supply in tetrode amplifiers.
>Datum: 2024-12-18T17:28:55+0100
>Von: "Lukasz" <sp4it.mail at gmail.com>
>An: "ka4inm at gmail.com" <ka4inm at gmail.com>
>
>On Wed, 18 Dec 2024, 14:26 Ron W4BIN, <ka4inm at gmail.com> wrote:
>
>   ?ukasz 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,
>?ukasz - SP4IT
>_______________________________________________
>Amps mailing list
>Amps at contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
>?
>
>
>
>------------------------------
>
>Message: 2
>Date: Thu, 19 Dec 2024 01:16:09 +0100
>From: Lukasz <sp4it.mail at gmail.com>
>To: dj7ww at t-online.de
>Cc: ka4inm at gmail.com, amps at contesting.com
>Subject: Re: [Amps] Acceptable ripple on high voltage plate power
>	supply in tetrode amplifiers.
>Message-ID:
>	<CADuTvfrEQXH5nporz4_MH+w6XYhRN5zS9E1j=K=BuvGTEV=2WQ at mail.gmail.com>
>Content-Type: text/plain; charset="UTF-8"
>
>On Wed, 18 Dec 2024, 20:01 dj7ww at t-online.de, <dj7ww at t-online.de>
>wrote:
>
>> I use 2?F and no choke with my 3-phase DB6  power supply and nobody
>hears
>> any hum.
>
>
>Very interesting.
>
>Have you ever measured the ripple? If so, what is it?
>
>If you haven't, please give some details of the PSU so I can
>guesstimate
>it. What AC/DC voltage and current do you use, is it a normal 3 phase
>full
>wave rectifier (50 or 60Hz?) or something else (like a doubler, or half
>wave etc).
>
>Also, have you had a chance to see a waterfall of your SSB signal? I
>wonder
>if the correspondents can't hear it has to do with the fact everything
>under 300Hz is cut off on their end, or there is no hum transmitted? An
>waterfall would show any 200Hz peak.
>
>>
>>
>> Check with Dr.Alex if you need larger capacitors:
>> http://www.ur4ll.net/#caps1
>
>Thanks, I've got plenty, but no doubt someone else might need it.
>
>73,
>?ukasz - SP4IT
>
>>
>>
>>
>>
>
>
>------------------------------
>
>Message: 3
>Date: Thu, 19 Dec 2024 06:48:45 -0300
>From: Juan Pablo Ravinale <janlu5yf at gmail.com>
>To: amps at contesting.com
>Subject: [Amps] Mercado Libre Amplifiers, Transceivers, and More
>Message-ID:
>	<CAG2VEqAnoqho4LBDw4qDjRbxPRVM8VLGnwestZq+ZAVCjKdwXw at mail.gmail.com>
>Content-Type: text/plain; charset="UTF-8"
>
>Dear People :
>
>Mercado Libre, from Argentina, has started 12/16/2024 to offer U.S.
>products in Argentina.
>For us, it will be more easy to buy something new or in second hand.
>
>Cheers!
>
>Juan, LU5YF
>
>
>------------------------------
>
>Subject: Digest Footer
>
>_______________________________________________
>Amps mailing list
>Amps at contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
>
>
>------------------------------
>
>End of Amps Digest, Vol 264, Issue 14
>*************************************