Folks,
Some things to consider using toroids with tube circuits.
As Monty's neat ALTOOB rig demonstrates, modern components and tubes do mix.
I'd suggest using only iron powder cores for tuned circuits. Ferrite will
be magnetically charged when a voltage is applied to the winding. Might be
OK for RF chokes but any resonant inductance you have with ferrite will
change with the level of magnetic charge.
Even with the use of modern wire coatings, the sharp edges of some toroids
will cut through the insulation. Edges seem to be sharper with ferrite than
with iron powder too. You could end up with the core being shorted to your
B+ voltage.
Chuck Carpenter, W5USJ, Point, Rains Co., TX - EM22cv, NETXQRP #1
QRP-ARCI #5422, QRP-L #1306, SOC #57, 6 Club #201, SMIRK #6275
Zombie #759, QRPp-I #115, COG #11, NETXQRP http://www.netxqrp.org
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