Ampdog
R.I.P. 23 June 2022
One sometimes hears/reads about resistors being inductive, as in meant as a warning.
Although well-intentioned, it is a meaningless statement unless qualified. In the limit even p.c. board tracks are inductive, as is the wiring of any amplifier. Sometimes it is obvious that there will be no effect in audio, but to the uninitiated it might cause unnecessary worry. The 'in audio' are the key words. Yes, wire wound resistors suggest themselves, but even there the inductance is mostly too low to play a role in audio. (It should also be noted that in wire wound resistors the windings often 'doubles back' on themselves, thus further countering inductivity. It can however do no harm to be aware and check your build!)
Regarding one specific example: In s.s amplifiers the 'problem' most often concerns emitter resistors in the power stage, even though those are mostly < 1 ohm. However, I have just read on another forum that somebody did apparently have trouble with inductive emitter resistors, although his experience was subsequently questioned.
Thus: Have any members on our forum ever had problems that could be traced to inductive resistors, specifically emitter w.w. resistors - but also other confirmed events? I recall that member Gecko (where has he gone?) specifically mentioned such an incident. I would appreciate discussion on this.
[P.S: In high-gain amplifiers with NFB, problems might arise with stability at super audio frequencies, but which could be easily addressed.]
Although well-intentioned, it is a meaningless statement unless qualified. In the limit even p.c. board tracks are inductive, as is the wiring of any amplifier. Sometimes it is obvious that there will be no effect in audio, but to the uninitiated it might cause unnecessary worry. The 'in audio' are the key words. Yes, wire wound resistors suggest themselves, but even there the inductance is mostly too low to play a role in audio. (It should also be noted that in wire wound resistors the windings often 'doubles back' on themselves, thus further countering inductivity. It can however do no harm to be aware and check your build!)
Regarding one specific example: In s.s amplifiers the 'problem' most often concerns emitter resistors in the power stage, even though those are mostly < 1 ohm. However, I have just read on another forum that somebody did apparently have trouble with inductive emitter resistors, although his experience was subsequently questioned.
Thus: Have any members on our forum ever had problems that could be traced to inductive resistors, specifically emitter w.w. resistors - but also other confirmed events? I recall that member Gecko (where has he gone?) specifically mentioned such an incident. I would appreciate discussion on this.
[P.S: In high-gain amplifiers with NFB, problems might arise with stability at super audio frequencies, but which could be easily addressed.]
