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From: liz@poppyrecords.invalid.invalid (Liz Tuddenham)
Newsgroups: sci.electronics.design
Subject: Re: big L
Date: Sat, 21 Dec 2024 22:01:36 +0000
Organization: Poppy Records
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Cursitor Doom <cd@notformail.com> wrote:

> On Sat, 21 Dec 2024 11:35:54 -0800, john larkin <JL@gct.com> wrote:
> 
> >On Sat, 21 Dec 2024 16:53:07 +0000, Cursitor Doom <cd@notformail.com>
> >wrote:
> >
> >>On Sat, 21 Dec 2024 11:16:18 -0500, legg <legg@nospam.magma.ca> wrote:
> >>
> >>>On Tue, 17 Dec 2024 06:58:32 -0800, john larkin <JL@gct.com> wrote:
> >>>
> >>>>What's the biggest inductor, the most Henries, that you know of? I
> >>>>seem to recall some audio transformer that was something like 100 H.
> >>>
> >>>The SAFT/Alcatel plant in Scarborough used to have 
> >>>largish inductors for loading. Air-cored - ~10ft 
> >>>on a side.
> >>>
> >>>Your watch would stop, if you were too close.
> >>>
> >>>Large L ? Who needs it?
> >>
> >>In the olde days we used to have audio output transformers  for
> >>impedance matching purposes, but modern amps don't seem to need 'em.
> >
> >And long ago tubes were expensive so it made sense to get voltage gain
> >from interstage transformers.
> 
> Indeed. And that's just one aspect of it. The designers in the early
> stage of toob development deserve huge respect for the performance
> they were able to wring out of a single stage - and all just to save
> the hard-pressed consumer back in the day a few sheckles.

Have a look at:
<http://www.poppyrecords.co.uk/httpdocs/other/AMC5.pdf>
as an example of incredibly efficient design.  It took the output from a
ribbon mic and raised it to 0dBm line level.  By using a mixture of
current and voltage feedback, it terminated the mic correctly without
the need for a terminating resistor, which would have wasted signal
power and generated Johnson noise.

-- 
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk