Resistor type, quality, location. ???

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David Root
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Re: Resistor type, quality, location. ???

Post by David Root »

IIRC, (I could be wrong) CC resistors need around 200V across them to generate the prized 2nd harmonics. If that be so, then indeed the only place you're likely to find that is in the PI.

Also IIRC, 1/2W will generate more such harmonics than 1W in the same spot, but I would not undercut the rating to do that. I like 3.0 SF or better on quiescent DC power though, and higher on power tube screens or cathodes. And I don't use 1/4W resistors ever.

I've used Takman, Riken CF, Mills and Dale wirewounds, PRP MF, and also 20 cent "Stackpole" CF 2W, which are OK specwise but have thinner leads than the old stuff, and the leads are steel, and the caps are magnetic, (but I don't worry about the last two parameters).

I've also built amps using whatever was on hand, and they sound OK too.

Voltage and wattage rating is the basics, the rest is "to taste".
When I was a boy I was told that anyone could become President. I`m beginning to believe it--Clarence Darrow
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Leo_Gnardo
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Re: Resistor type, quality, location. ???

Post by Leo_Gnardo »

Phil_S wrote:
cbass wrote:I only like resistors that you can't get anymore
I can get you some of those. :shock:
Me too, got bags of 'em. All out of spec but so what. "Dog bones" from the 20's on up. For hysterical porpoises of course, not recommended for actual builds.
down technical blind alleys . . .
Firestorm
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Re: Resistor type, quality, location. ???

Post by Firestorm »

Fun topic. Resistors are just noisy little things and depending on type can add one or two or three types of noise. Mr. Keen is smarter than me by at least an order of magnitude, so I'll defer to him. But, cosmetics aside, resistors perform a function. No mojo, no magic. Anything Class A will be predominantly 2nd order harmonics. Every preamp you've ever seen, every SE output. The quirky thing is the DC coupled cathode follower, designed, I think, by Alan Blumlein, analyzed by Merlin Blencowe (both Brits, appropriately).

Design it wrong and lovely things happen.
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Gainzilla
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Re: Resistor type, quality, location. ???

Post by Gainzilla »

Hi all,

Thanks for all the great contributions to this thread. I think I got exactly what I needed. A little bit of tough love coupled with some solid experience-backed guidance! So it sounds like, for this build, I'll just stick with the solid .20 cent metal film (or Carbon film for 350v + applications - great tip!). resistors from recognized manufacturers (though I'll probably play around with CC in the PI area).

Ok, now what about capacitors? J/K. 😜
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