Hi


Ruud Broens:

Found a site with loads of tubes in the $ 0.25 - 0.35 range.
All sorts of Vfil and Ifil on these .
So what about using these baby's as series resistor in a
------R-----|------R-------
C
|
power supply filter ?
At somewhat below it's rated Vfil and Ifil you'll get
It will Rhotfil lower resistance as Isupply rises
and Rcoldfil will raise it's resistance at lower current
making for a nice local grid fluctuations and weird
out of spec juice regulation.

Anyone tried that yet ?
Hope so, tell us,
Rudy


Are you sure? I thought R went up as temp increased.

Your idea sounds like baretters, which were used in the 30s. Iron wire
in hydrogen I think, they had a region where i was more or less the
same for varying V, so were used to stabilise supplies.

Regards, NT

Yes, flushin' cheeks,
realized that just after.
But then thought about using 'm as
loads in a parallel regulator scheme.
Still in the !todo! i'm afraid, as it
turned out the us vendor didn't want
to ship out to europe, too much bother
at the time to arrange through US
family. Let me check that link:
http://www.moyerelectronics.com/index.html

some of my notes:
11CF11 compactron 12 pins!; triode 1 driver Ia=7mA, Ra=15K,
+170Va

0,35 USD
17AX4 octal, 16.8V 450 ma =~ 37 Ohm filament damper diode
0,25 USD

eg, this last one, use 5 in parallel (filaments) as an
interesting amplifier load

Happy searching there !
Rudy

"N. Thornton" wrote in message
om...
: Hi
:
:
: Ruud Broens:
:
: Found a site with loads of tubes in the $ 0.25 - 0.35 range.
: All sorts of Vfil and Ifil on these .
: So what about using these baby's as series resistor in a
: ------R-----|------R-------
: C
: |
: power supply filter ?
: At somewhat below it's rated Vfil and Ifil you'll get
: It will Rhotfil lower resistance as Isupply rises
: and Rcoldfil will raise it's resistance at lower current
: making for a nice local grid fluctuations and weird
: out of spec juice regulation.
:
: Anyone tried that yet ?
: Hope so, tell us,
: Rudy
:
:
: Are you sure? I thought R went up as temp increased.
:
: Your idea sounds like baretters, which were used in the 30s. Iron wire
: in hydrogen I think, they had a region where i was more or less the
: same for varying V, so were used to stabilise supplies.
:
: Regards, NT

"Ruud Broens" wrote in message news:3fc00a2b$0$217: :
: :
: :
: : Are you sure? I thought R went up as temp increased.
:
yep, does so, my mistake
: : Your idea sounds like baretters, which were used in the 30s. Iron wire
: : in hydrogen I think, they had a region where i was more or less the
: : same for varying V, so were used to stabilise supplies.
: :
: : Regards, NT
:
Group, going back to lurkin' mode for a while now,
work piling up here.
Filaments, damn things fascinate me

Something worth scouting perhaps:

- Klaus' site, some interesting results with lowering
heater power - reducing the space-charge promising
more linear triode operation see russian curves

- Neuman micr. discussion ?, not sure,
take a new pre-amp stage triode (or-strapped),
initial 'ritual' 5 minutes of 4V to 7V filament voltage
(nom. 6.3V type), 1Hz oscillator. this causes barium
cathode layer 'refreshment', a bit like thorium works
in a DH power triode. reduces cathode generated
noise part in total noise. subsequently operate it
with a slow upramping regulated supply,
for you to experiment with supply voltage.
Svetlana
tech says it works fine,
esp. with NOS.

Happy Xperimentin',
Rudy