Someone who likes talking about how tube amps might be interested in it.
https://www.ampbooks.com/mobile/amp-technology/hughes-kettner/
"The Hughes & Kettner Switchblade 100 Head has two ECC83/12AX7 dual triodes and four EL34 power pentodes. The triodes implement a voltage amplifier, a DC-coupled cathode follower, and a long-tailed-pair phase inverter in classic Bassman 5F6-A style. Hughes & Kettner then expands upon its Fender/Marshall core to create a switched-channel, MIDI-controlled performance powerhouse:
Relays
The Switchblade uses TQ2-24V relays.
TQ2-24V relay
They are single side stable, so they turn on when the coil between pin 1 and pin 10 is excited and off when it is unexcited. When the coil is deenergized, pin 8 connects to pin 9 and pin 3 connects to pin 2. When the coil is energized pin 8 connects to pin 7 and pin 3 connects to pin 4."
I don't understand much of this but maybe someone might lol.
https://www.ampbooks.com/mobile/amp-technology/hughes-kettner/
"The Hughes & Kettner Switchblade 100 Head has two ECC83/12AX7 dual triodes and four EL34 power pentodes. The triodes implement a voltage amplifier, a DC-coupled cathode follower, and a long-tailed-pair phase inverter in classic Bassman 5F6-A style. Hughes & Kettner then expands upon its Fender/Marshall core to create a switched-channel, MIDI-controlled performance powerhouse:
Relays
The Switchblade uses TQ2-24V relays.
TQ2-24V relay
They are single side stable, so they turn on when the coil between pin 1 and pin 10 is excited and off when it is unexcited. When the coil is deenergized, pin 8 connects to pin 9 and pin 3 connects to pin 2. When the coil is energized pin 8 connects to pin 7 and pin 3 connects to pin 4."
I don't understand much of this but maybe someone might lol.