http://www.circuitstoday.com/audio-distortion-meter An Authentic Resource on Electronics Wed, 08 Feb 2012 02:09:28 +0000 hourly 1 http://wordpress.org/?v= http://www.circuitstoday.com/audio-distortion-meter#comment-10018 Dom Wed, 17 Nov 2010 12:44:05 +0000 http://www.circuitstoday.com/?p=137#comment-10018 A utc vc 15 variable inductor refers to vintage variable inductor circa 1950's and would require a 1300mH variable inductor to attain 1 Khz. I would suggest that a C value of 0.33uF each and a variable inductor centred around 38.4 mH should give a high Q with a high R (250K) therefore notch at 1 Khz according to parallel resonant circuit calculation. The 1 Khz signal input to the amp under test could be built using the op amps from National Semiconductor LT1115, the pdf spec sheet gives an application for a sinewave oscillator with 5 ppm distortion. A utc vc 15 variable inductor refers to vintage variable inductor circa 1950′s and would require a 1300mH variable inductor to attain 1 Khz. I would suggest that a C value of 0.33uF each and a variable inductor centred around 38.4 mH should give a high Q with a high R (250K) therefore notch at 1 Khz according to parallel resonant circuit calculation. The 1 Khz signal input to the amp under test could be built using the op amps from National Semiconductor LT1115, the pdf spec sheet gives an application for a sinewave oscillator with 5 ppm distortion.

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