Why do some manufacturers claim relays are the best way to switch effects?
Relays are a good solution as they are, in fact, remotely controlled mechanical switches. The problem with a mechanical switch, however, is the transient switch noise caused by the contacts arcing as they approach each other. We use relays in several Radial products, but relegate these to applications where the signal will not be an amplified one. For devices that pass audio before a guitar amplifier, we prefer to use opto-couplers. These devices can be used to perform various functions and in this case, we use them like a switch with a programmed ramp-up and ramp-down time. This means that the signal does not ‘click’ on but actually rises to an ‘on’ status, eliminating the transient that causes a click or pop. Some older amps switched channels using opto-couplers (also known as photocells), but today most amps use other electronic switching methods due to the higher cost of opto-couplers and supporting circuitry.
