This circuit is placed between the instrument pickup and the amplifier input. The same version can be found from other sources in this section. This is from an English magazine from the 80s.
This circuit was found in an old Electronic Design. It makes use of sidacs and operational not very...
Although it was found in a British magazine 1976, this circuit can be easily upgraded with the...
This circuit that uses only transistors that are still common was found in a 1995 documentation. The TIP41...