[NJARC] Tubes for clinic

[Mike Feher]

John -

An 8 ohm resistor will never look like a short at any frequency since it's
reactive component, whether it be inductive or capacitive, will always add
on to the 8 ohm resistive part. For testing purposes for audio amplifiers it
is a good way to go. You will need a lot of inductance to really make any
difference at audio frequencies. 73 - Mike

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960




-----Original Message-----
From: njarc-bounces at mailman.qth.net [mailto:njarc-bounces at mailman.qth.net]
On Behalf Of John Ruccolo
Sent: Sunday, February 21, 2010 10:50 AM
To: njarc at mailman.qth.net; Jim Whartenby
Subject: Re: [NJARC] Tubes for clinic

Just remember 
Reply = Poster
Reply All = Everyone

_________________________________________________________
Hi Jim,

Good point, but I was only tellling what it says on the resistors: 8 Ohm
NON-IND.

I'm out of my league with all the highly mathematical engineering stuff, but
I will speculate: a speaker VC is really a *solenoid* winding of sorts,
(around the PM core), where a normal wire-wound power resistor is merely an
air-wound coil with ceramic filling replacing the air. So, their
characteristics must be a little different.

Perhaps there is a frequency range where an 8-ohm WW resistor will look like
a dead short to the amplifier (at "resonance?"), instead of an 8-ohm load. I
imagine that would be a problem, *especially* for a solid-state amp.

Regards,

John