Yes, I realize there is thermal inertia, so we wouldn't get any distorsion in the normal sense, like THD. However, what if there is a fortissimo passage so the resistor will dissipate a high power for a while. It will warm up slowly and if it is the feedback resistor, that means the gain of the amp will change slowly. Whether such an effect would be audible is another issue.
Carbon comps absorb humidity over time -- and the values change -- particularly true if you are using a carbon comp for the plate resistor in a preamp -- where it's going to get heated.
Carbon comps resistance becomes non-linear above a few hundred volts.
If you have a problem with the "drill-size" for the Allen Bradley cc resistors, just create a new component in your pcb software with the proper drill size.
The 1/4 and 0.4 w Yaego metal film resistors sold by Digikey use a 21 mil drill. A 1/2 W AB uses a 27 mil drill, 1 Watt AB use a 39 mil drill, for 2W use a 49 mil drill.
Carbon comps resistance becomes non-linear above a few hundred volts.
If you have a problem with the "drill-size" for the Allen Bradley cc resistors, just create a new component in your pcb software with the proper drill size.
The 1/4 and 0.4 w Yaego metal film resistors sold by Digikey use a 21 mil drill. A 1/2 W AB uses a 27 mil drill, 1 Watt AB use a 39 mil drill, for 2W use a 49 mil drill.
A lot of good info about different resistors can be found in Ben Duncan article "Piece de resistance" (recommended):
The Audio Amateur, 1994, 2-4, (revised and expanded).
Reprinted from: Hi-Fi News & Record Review, 1987, March.
Every good local library will have them.
You can find useful info about carbon composition resistors in "Art of Electronics" (Horowitz & Hill), p. 372, fig. 6.53.
The Audio Amateur, 1994, 2-4, (revised and expanded).
Reprinted from: Hi-Fi News & Record Review, 1987, March.
Every good local library will have them.
You can find useful info about carbon composition resistors in "Art of Electronics" (Horowitz & Hill), p. 372, fig. 6.53.
Dear Christer:
In the past, I have posted about nearly the same thing as you and Upupa Epops. Please see the following:
NFB resistor types vs. THD.
hth, jonathan carr
In the past, I have posted about nearly the same thing as you and Upupa Epops. Please see the following:
NFB resistor types vs. THD.
hth, jonathan carr
Sorry Jonathan, I had either missed that thread or forgotten about it. Of course, if I get an idea or make an "invention", I never assume I am the first or the only one to do so, just because I cannot remember ever reading about it before. This issue is however, obviously not a commonly observerd phenomen on this forum, so it seemed interesting to bring it up. The reasons why it is not more widespread knowledge could be many, perhaps many of the professionals already know and practice this but prefer to keep it their secret, for instance? You would then obviously be an exception, since you have mentioned it before.
Vishay (the very expensive ones): You cant hear them!
Caddock: US style lower registers - loosen and woody, not much detail but clean.
Holco: Slow, dull, very woody bass.
Riken (new carbon): Correct rhythm, strong but clear. Sweet highs.
Roederstein, Beyschlag (metal film): Highs are a bit problematic - tad too much and not very clear. Dry bass & much detail. Could be more organic.
Old carbon types: Slow, muddy, dull, lifeless, missing treble, loosy bass, missing space & 3D. Hissy with high distortion factor. I will never understand the people using this crapp.
Caddock: US style lower registers - loosen and woody, not much detail but clean.
Holco: Slow, dull, very woody bass.
Riken (new carbon): Correct rhythm, strong but clear. Sweet highs.
Roederstein, Beyschlag (metal film): Highs are a bit problematic - tad too much and not very clear. Dry bass & much detail. Could be more organic.
Old carbon types: Slow, muddy, dull, lifeless, missing treble, loosy bass, missing space & 3D. Hissy with high distortion factor. I will never understand the people using this crapp.
ElectricHead said:
I notice you didn't mention the date codes of the resistors to which you listened. Some of them mellow nicely with age, and if you store them properly, they make great investments!
I find the Rikens to age well at 55 degrees F for at least 3 years when stored in French oak crates (NOT hillside oaks, but valley oaks- something about the extra moisture adds fragrance to the finish).
Caddocks on the other hand are as bitter-sweet as bitter-sweet can be. Nice cinnamon overtones. Best used within 6 months of production.
Finally, the Beyschlags- they remind me of a girl I dated in college- they start sweet and attentive only to come to a cloying and bitter finish. Best not to even start with them....
I_F
Upupa, please drop the personal stuff. People get their kicks in different ways.
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