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Groups > uk.tech.broadcast > #70623

Re: OT - TV

From John Williamson <johnwilliamson@btinternet.com>
Newsgroups alt.comp.os.windows-11, alt.comp.os.windows-10, comp.os.linux.advocacy, comp.os.linux.misc, uk.tech.broadcast
Subject Re: OT - TV
Date 2026-09-30 11:19 +0100
Message-ID <ni461gFe04aU1@mid.individual.net> (permalink)
References (13 earlier) <119e25d$2ffig$3@dont-email.me> <119g5q3$37679$1@dont-email.me> <119gmur$3e4ln$1@dont-email.me> <j91vomxksl.ln2@Telcontar.valinor> <ni45lsFdufrU1@mid.individual.net>

Cross-posted to 5 groups.

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On 30/09/2026 11:13, John Williamson wrote:
> On 30/09/2026 10:27, Carlos E.R. wrote:
>> On 2026-09-29 17:54, Jan Panteltje wrote:
>
>>> Yes some tube TVs had 800 Ohm speakers without transformers.
>>>
>>> Example of a tube output stage without transformer to drive a 800 Ohm
>>> speaker:
>>>
>>> https://2.bp.blogspot.com/-GaJkZ9klfLw/VOecHjVgPuI/AAAAAAAAA4g/H2qcMWJ3tuA/s1600/Schema.png
>>>
>>>
>>
>> I'm not familiar with valves EZ80 and 6CA4, I don't understand the
>> drawings. :-?
>>
> The EZZ80 and BCA4 valves are full wave rectifiers in the power supply.
> (Equivalent to two diodes in each  valve, with a tapped transformer
> secondary. Back when semiconductors were expensive, I've done similar
> with a pair of germanium diodes, as it was cheaper than a bridge
> rectifier.)i
>
> The relevant stage for this thread is the output stage, which is two
> EL504 pentodes being driven in a sort of push-pull configuration by the
> input triode. The EL504s each have an independent DC supply.
>
> The circuit specifies an 800 ohm load, but I first expected to see a
> more standard 600 ohm load...
>
Sorry, my mistake, the EL504s use the bottom one being driven to conduct 
more which pulls the cathode voltage of the other down, making it a 
class A output stage.

<Note to self. Visit the optician>:-)

The other supply is for the input triode.

-- 
Tciao for Now!

John.

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Thread

Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-26 19:08 +0100
  Re: OT - TV Scott <newsgroups@gefion.myzen.co.uk> - 2026-09-26 19:58 +0100
    Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-26 20:30 +0100
      Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-27 09:39 +0100
      Re: OT - TV JMB99 <mb@nospam.net> - 2026-09-28 08:08 +0100
  Re: OT - TV Frank Slootweg <this@ddress.is.invalid> - 2026-09-26 19:10 +0000
    Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-26 21:02 +0100
      Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-26 21:03 +0100
        Re: OT - TV Frank Slootweg <this@ddress.is.invalid> - 2026-09-27 18:20 +0000
          Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-28 16:26 +0100
            Re: OT - TV Frank Slootweg <this@ddress.is.invalid> - 2026-09-28 15:45 +0000
            Re: OT - TV Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2026-09-28 16:30 +0000
              Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-28 17:46 +0100
                Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-28 22:25 +0100
                Re: OT - TV NY <me@privacy.net> - 2026-09-29 16:40 +0100
                OT - Lehrer (was: Re: OT - TV) "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-29 16:58 +0100
                Re: OT - Lehrer (was: Re: OT - TV) Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2026-09-29 18:19 +0000
                Re: OT - Lehrer "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-29 20:57 +0100
                Re: OT - Lehrer Charles Hope <clh@candehope.me.uk> - 2026-09-29 20:00 +0000
                Re: OT - Lehrer (was: Re: OT - TV) André Coutanche <acoutanche@gmx.co.uk> - 2026-09-29 21:50 +0100
                Re: OT - Lehrer NY <me@privacy.net> - 2026-09-29 22:33 +0100
                Re: OT - Lehrer Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2026-09-29 22:48 +0000
                Re: OT - Lehrer "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-30 01:07 +0100
                Re: OT - Lehrer John Ames <commodorejohn@gmail.com> - 2026-09-30 15:51 -0700
                Re: OT - Lehrer NY <me@privacy.net> - 2026-10-01 10:57 +0100
                Re: OT - Lehrer NY <me@privacy.net> - 2026-09-30 08:10 +0100
                Re: OT - Lehrer "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-30 01:39 +0100
                Re: OT - Lehrer Roger Blake <rogblake@iname.invalid> - 2026-09-30 00:46 +0000
                Re: OT - Lehrer NY <me@privacy.net> - 2026-09-29 22:39 +0100
                Re: OT - Lehrer Frank Slootweg <this@ddress.is.invalid> - 2026-09-30 12:25 +0000
                Re: OT - Lehrer "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-30 13:34 +0100
                Re: OT - Lehrer The Natural Philosopher <tnp@invalid.invalid> - 2026-09-30 14:31 +0100
                Re: OT - Lehrer NY <me@privacy.net> - 2026-09-30 14:47 +0100
                Re: OT - Lehrer John Williamson <johnwilliamson@btinternet.com> - 2026-09-30 14:58 +0100
                Re: OT - Lehrer "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-10-01 02:36 +0100
                Re: OT - Lehrer NY <me@privacy.net> - 2026-10-01 11:12 +0100
                Re: OT - Lehrer Frank Slootweg <this@ddress.is.invalid> - 2026-10-01 14:35 +0000
                Re: OT - Lehrer NY <me@privacy.net> - 2026-10-01 16:14 +0100
                Re: OT - Lehrer Frank Slootweg <this@ddress.is.invalid> - 2026-10-01 17:35 +0000
                Re: OT - Lehrer Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2026-10-01 17:53 +0000
                Re: OT - Lehrer John Williamson <johnwilliamson@btinternet.com> - 2026-10-01 19:03 +0100
                Re: OT - Lehrer "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-10-01 21:50 +0100
                Re: OT - Lehrer The Natural Philosopher <tnp@invalid.invalid> - 2026-10-02 12:25 +0100
                Re: OT - Lehrer The Natural Philosopher <tnp@invalid.invalid> - 2026-10-01 11:13 +0100
                Re: OT - Lehrer NY <me@privacy.net> - 2026-10-01 11:51 +0100
                Re: OT - Lehrer John Williamson <johnwilliamson@btinternet.com> - 2026-09-30 14:55 +0100
                Re: OT - Lehrer Charles Hope <clh@candehope.me.uk> - 2026-09-30 14:15 +0000
    Re: OT - TV Daniel70 <daniel47@nomail.afraid.org> - 2026-09-27 19:58 +1000
      Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-27 12:52 +0100
        Re: OT - TV Daniel70 <daniel47@nomail.afraid.org> - 2026-09-27 22:13 +1000
    [OT] - audio distribution, Rediffusion-style (was: Re: OT - TV) "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-28 16:43 +0100
  Re: OT - TV Max Demian <max_demian@bigfoot.com> - 2026-09-27 11:44 +0100
    Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-27 16:12 +0100
      Re: OT - TV Max Demian <max_demian@bigfoot.com> - 2026-09-27 18:12 +0100
        Re: OT - TV Andy Burns <usenet@andyburns.uk> - 2026-09-27 18:23 +0100
        Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-27 18:34 +0100
          Re: OT - TV Max Demian <max_demian@bigfoot.com> - 2026-09-28 14:03 +0100
            Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-28 15:56 +0100
            Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-28 16:46 +0100
              Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-28 17:16 +0100
              Re: OT - TV Max Demian <max_demian@bigfoot.com> - 2026-09-29 12:01 +0100
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-29 13:05 +0100
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-29 13:25 +0100
                Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-29 14:13 +0100
                Re: OT - TV The Other John <nomail@here.org> - 2026-09-29 16:53 +0100
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-29 17:12 +0100
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-30 10:22 +0100
                Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-09-30 13:36 +0100
                Re: OT - TV "Carlos E.R." <robin_listas@es.invalid> - 2026-09-30 11:23 +0200
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-30 11:48 +0100
                Re: OT - TV Paul <nospam@needed.invalid> - 2026-09-30 07:37 -0400
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-30 14:28 +0100
                Re: OT - TV "Carlos E. R." <robin_listas@es.invalid> - 2026-10-01 00:35 +0200
                Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-10-01 02:15 +0100
                Re: OT - TV Paul <nospam@needed.invalid> - 2026-10-01 00:15 -0400
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-10-01 12:50 +0100
                Re: OT - TV "Carlos E. R." <robin_listas@es.invalid> - 2026-10-01 14:24 +0200
                Re: OT - TV Max Demian <max_demian@bigfoot.com> - 2026-10-01 17:17 +0100
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-10-01 12:48 +0100
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-10-01 13:10 +0100
                Re: OT - TV John Williamson <johnwilliamson@btinternet.com> - 2026-10-01 13:42 +0100
                Re: OT - TV John Williamson <johnwilliamson@btinternet.com> - 2026-10-01 13:32 +0100
                Re: OT - TV Frank Slootweg <this@ddress.is.invalid> - 2026-10-01 14:52 +0000
                Re: OT - TV Daniel70 <daniel47@nomail.afraid.org> - 2026-10-03 21:10 +1000
                Re: OT - TV "Carlos E. R." <robin_listas@es.invalid> - 2026-10-03 13:39 +0200
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-10-03 12:47 +0100
                Re: OT - TV John Williamson <johnwilliamson@btinternet.com> - 2026-10-03 12:50 +0100
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-10-03 13:09 +0100
                Re: OT - TV John Williamson <johnwilliamson@btinternet.com> - 2026-10-03 15:59 +0100
                Re: OT - TV Jan Panteltje <alien@comet.invalid> - 2026-10-03 15:56 +0000
                Re: OT - TV Roderick Stewart <rjfs@escapetime.myzen.co.uk> - 2026-09-30 15:13 +0100
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-29 13:16 +0100
                Re: OT - TV Jan Panteltje <alien@comet.invalid> - 2026-09-29 15:54 +0000
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-29 17:15 +0100
                Re: OT - TV "Carlos E.R." <robin_listas@es.invalid> - 2026-09-30 11:27 +0200
                Re: OT - TV John Williamson <johnwilliamson@btinternet.com> - 2026-09-30 11:13 +0100
                Re: OT - TV John Williamson <johnwilliamson@btinternet.com> - 2026-09-30 11:19 +0100
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-30 11:57 +0100
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-30 13:29 +0100
                Re: OT - TV John Williamson <johnwilliamson@btinternet.com> - 2026-09-30 13:54 +0100
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-30 14:34 +0100
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-30 18:08 +0100
                Re: OT - TV "J. P. Gilliver" <G6JPG@255soft.uk> - 2026-10-01 02:22 +0100
                Re: OT - TV Jan Panteltje <alien@comet.invalid> - 2026-10-01 06:37 +0000
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-10-01 10:32 +0100
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-10-01 09:41 +0100
                Re: OT - TV "Carlos E. R." <robin_listas@es.invalid> - 2026-10-01 00:37 +0200
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-09-30 11:50 +0100
                Re: OT - TV Jan Panteltje <alien@comet.invalid> - 2026-09-30 13:08 +0000
                Re: OT - TV "Carlos E. R." <robin_listas@es.invalid> - 2026-10-01 00:50 +0200
                Re: OT - TV Jan Panteltje <alien@comet.invalid> - 2026-10-01 06:12 +0000
                Re: OT - TV c186282 <c186282@nnada.net> - 2026-10-01 03:29 -0400
                Re: OT - TV "Carlos E. R." <robin_listas@es.invalid> - 2026-10-01 14:53 +0200
                Re: OT - TV Paul <nospam@needed.invalid> - 2026-10-01 03:32 -0400
                Re: OT - TV "Carlos E. R." <robin_listas@es.invalid> - 2026-10-01 14:49 +0200
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-10-01 12:57 +0100
                Re: OT - TV liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-10-01 13:27 +0100
                Re: OT - TV "Carlos E. R." <robin_listas@es.invalid> - 2026-10-01 15:19 +0200
                Re: OT - TV Jan Panteltje <alien@comet.invalid> - 2026-10-01 14:34 +0000
                Re: OT - TV The Natural Philosopher <tnp@invalid.invalid> - 2026-10-01 15:51 +0100
                Re: OT - TV Jan Panteltje <alien@comet.invalid> - 2026-10-02 06:52 +0000
  Re: OT - TV "Carlos E.R." <robin_listas@es.invalid> - 2026-09-27 13:12 +0200

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