teddy_pardo
Trade: Teddy Pardo
While doing distortion measurements on some preamplifiers I discovered incidentally that ALPS (blue velvet, those used by Naim) introduce distortions. The distortion level depends very much on the potentiometer position. At low volume levels 7-12 (o'clock) distortion level is acceptable, but at high volume levels between 12-4 distortion can be very high, it can grow to around 0.5% !!!
Obviously at full volume the distortion level introduced by the potentiometer is near zero.
The results were consistent with several potentiometers that I tried (10K and 20K logarithmic). The explanation may be related to the fact that at high volume levels the surface on logarithmic potentiometer is different (changes more rapidly per mm).
Anyhow, those who reduce the peramp gain, think (or listen) again...
Teddy
Obviously at full volume the distortion level introduced by the potentiometer is near zero.
The results were consistent with several potentiometers that I tried (10K and 20K logarithmic). The explanation may be related to the fact that at high volume levels the surface on logarithmic potentiometer is different (changes more rapidly per mm).
Anyhow, those who reduce the peramp gain, think (or listen) again...
Teddy