The 808 in particular has an additional twist. The transistors used in it were out-of-spec rejected parts as a cost savings measure. So recreations and repairs

The 808 in particular has an additional twist. The transistors used in it were out-of-spec rejected parts as a cost savings measure. So recreations and repairs can have difficulty recapturing the signature sound if they go only by part number. https://secretlifeofsynthesizers.com/the-strange-heart-of-the-roland-tr-808/ https://secretlifeofsynthesizers.com/the-strange-heart-of-th...