This is the circuit for the HM-10ª, an instrument sold by Heathkit. The circuit is from a Radio Electronics from May 1963. The indication is by an analog instrument.
This circuit with the CA3130 has a feedback system that works as a lock. The circuit is from a...
This guitar effect circuit uses components that are still common in our market. We found the...
This circuit is from a 1967 US publication. The configuration can serve as a basis for designs...