Here is a modern day, greatly improved replacement for the old Reticon R5609 Anti-Aliasing Low Pass Filter used in the Kurzweil K250 12-channel synthesizer. These R5609 have not been made in many decades and are hard to get. In addition, these original chips were one of the primary limitations for distortion and noise in the K250. MAXIM makes a modern-day part (MAX291) that has been adapted to match the pinout of the R5609 and provides over 20dB lower distortion and 15dB lower noise. Includes one 8-pin socket per module.