Re: LTSpice model for a SiC MOSFET

john larkin <jl@glen--canyon.com> wrote:

On Thu, 22 May 2025 16:50:25 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
 

john larkin <jl@glen--canyon.com> wrote:
>

On Thu, 22 May 2025 09:44:30 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
 

john larkin <jl@glen--canyon.com> wrote:
>
[...]

Going from 1KV to 3.3v has interesting possibilities. The easy way is
a resistor and a zener. Efficiency about 0.3%.

>
Roughly 1W dissipation per mA , so if the current requirement isn't too
high, that is probably the most straightforward system with very little
to go wrong.
>
>

More efficient would be a resistor and a zener and then a buck
switcher. 5% maybe.

>
That's a lot of extra complication for very little improvement, the
resistor still has to carry the full load current.
>
For a cult market you could use an 807 and tap the 3.3v off the cathode
bias resistor.  (or better still, rectify the heater supply and use a
linear regulator but don't tell the customer).

 
I never liked 807's. Ugly tubes.

>
Ah yes.  For that market, appearance is everything. 
>
A much better-looking bottle would be a PY81 but, although it is
specified to withstand a peak anode voltage of 7 kV, the maunfacturers
only allow that under cutoff conditions.  It also uses a standard B9A
base, which is still easily obtainable.

 
A great audiophool prodcut would be a power amp with a pair of 833's
and lots of custom transformers and oil caps and things. Figure about
100 lbs and $30K.

I have recently been told of one - the output transformer alone cost UKP
9,000 and was wound with silver wire (probably spun by virgins at
midnight).

It amuses me that there is great prestige value put on using triodes
"with no negative feedback", completely ignoring the fact that triodes
have built-in non-linear negative feedback because of the influence of
the anode potential on the grid-cathode potential gradient.  A triode
with the negative feedback removed is called a 'Pentode'  ..but they are
condemned for being non-linear and "unmusical".


--
~ Liz Tuddenham ~
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www.poppyrecords.co.uk