[Johnson] Carbon composition resistors

Tue, 2 Dec 2003 11:34:46 -0800 (PST)

Thanks Roy for that great post. Where does all this myth about components come from? If anything, today's components are probably made to a higher stricter standard than the old days. FWIW. Cal, N6KYR. 

Roy Morgan <[email protected]> wrote:At 09:42 PM 11/30/03 -0500, Dave and Sharon Maples wrote:
>All: Hope everyone who celebrated Thanksgiving this week enjoyed it as much
>as we did here.
>
>I am now digging further into the Valiant II, and some of the carbon
>composition resistors (1/2 watt, 1 watt, and 2 watt) will need to be
>replaced. ...
>I am looking at some Ohmite ceramic composition resistors in Digi-Key, but
>I'm not convinced that they are the right choice here. Any comments?

They will work just FINE.

>From another post I just made to the Hammarlund list:

...

5) Claims that metal film resistors sound different than the old carbon 
composition ones in radios are also probably pure imagination. Again, in 
high end hi fi applications, they may in fact sound different in some 
spots. The high end audio folks say they do. I've never been in a 
position to hear the difference.

6) The use of resistors in impedance-sensitive RF attenuators is a special 
case, and for attenuators operating at mid-HF frequencies and up, the 
resistors must be of the right sort to perform properly.

7) Claims that metal film resistors, because they are made with spiral 
paths of resistive material on ceramic bodies, exhibit inductance that can 
cause trouble are almost always baloney. True, such inductance can be both 
calculated and measured. But, almost no resistor in any of our radios 
actually operates with significant RF currents. ("Stopper" resistors in 
grids of modulator or high fi power output tubes, and parasitic suppressor 
networks in the plates and grids of RF transmitting tubes are the only 
exceptions I can think of. Even there, the resistance values used are 
unlikely to cause any trouble even if they do have a bit of inductance.)

Roy

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Work: Voice: 301-975-3254, Fax: 301-948-6213
[email protected] --

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