Music made with computers is where it started with the MTU products.
Hal Chamberlin wrote many articles in e.g. Byte (see this page with his publications) and a hardware product supporting this is the K-1002 D/A 8 bit converter. It is to be connected to the application connector of KIM-1, SYM-1 or AIM 65.
Later a variant for the PET 2001 was produced with the name K-1002-2

The hardware is simple and uses standard components of the period, 1979.

K-1002 8-bit audio Digital to Analog Converter, for KIM-1, SYM-1 or AIM 65

The K-1002-2 8-bit audio Digital to Analog Converter for Commodore PET-2001.

	K-1002-2 8 bit audio Digital to Analog Converter Hardware Manual July 1979. With older MTU logo. For KIM-1, SYM-1, AIM 65 Application Connector
	K-1002-2 8 bit audio Digital to Analog Converter Hardware Manual Other version with new MTU logo. For KIM-1, SYM-1, AIM 65 Application Connector
	MTU k-1002-3 Source PET Music Software for PET 2001
	K-1002-2 8 bit audio Digital to Analog Converter for Commodore PET-2001 Hardware Manual
	MTU K-1002-L 8 bit Digital Music Software Simplified Interpreter Notran Interpreter Notran Compiler