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previous: Dai Hirokawa You know, if carbon comps were as b... -- 7/5/2003 11:00 PM View Thread

Re: What type of resistors are best?

7/6/2003 6:04 PM
Re: What type of resistors are best?
"old Fender amps would never have been the success that they were and still are. By this theory, they would have been too hissy and crackly right from the get go "
That's right, bring home an old Fender amp that has been used regularly over the years and it will be too hissy and crackly from the get go. To get rid of the noise you have to change out the carbon comp plate resistors, and maybe the screen resistors and voltage dropping resistors.  
"or gone quickly into a hissy, crackly, noise hell existence."
Not quickly, but eventually.  
I realize we're talking about what to put into an amp that you're going to build new, from fresh parts. So, maybe the builder won't mind using carbon comps because he'll have a good 10 to 15 years before he descends into a hissy, crackly, noise hell existence. But why bother getting carbon comps in the first place? According to the article on Geofex, they don't make any difference in tone except for creating asymmetrical distortion when you use them as plate load resistors in the second gain stage or higher. That's no reason to use them throughout the amp. Besides that, you'd probably have to get the old Allen Bradleys to hear that difference because the thermal coefficient of new carbon comps is much lower than it was in the old days. And I still don't see much reason to get them, because there are other ways to get second-order harmonic distortion that will never be the cause of hissing and crackling, not even twenty years from now.  
I have read one short post on Ampage suggesting that carbon comps might be preferable to metal films for grid stoppers because carbon comps have zero inductance, but I haven't read anything else to support or confirm that theory.  

Ben N FWIW, I have three SF Fenders, two ... -- 7/7/2003 7:02 PM