[sdiy] OP275 [was: Re: Audio mixers]

lanterma at ece.gatech.edu lanterma at ece.gatech.edu
Thu Jun 23 02:59:26 CEST 2011

Wow, he totally trashes the OP275:


"The Analog Devices OP275 is one of the few opamps specifically marketed as an audio device. Its most interesting characteristic is the Butler input stage; this combines bipolar and JFET devices. The idea is that the bipolars give accuracy and low noise, while the JFETs give speed and "the sound quality of JFETs". This final phrase is not a happy thing to see on a datasheet from a major manufacturer; the sound of JFETs (if any) would be the sound of high distortion. Let us however ignore this and see if the device actually works well. The datasheet includes a dissertation on "sound quality" which is not worth the ink expended in its last full stop. Expensive, and nothing special. Probably best avoided."

- Aaron

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