Q-LATCH – Quad Voice Controller for Guitar Amps

CAD $88.00CAD $168.00


London Power’s Q-LATCH voice controller is the heart of the Q-system of switching kits for guitar amps.

  • provides a 1-of-4 voice selection
  • expandable to any number of voices
  • use as front-panel control
  • use as remote foot-switch control
  • use for multiple foot-switch stage locations
  • 2-way communication between all switch stations
  • voice LED driver (4 LEDs)
  • internally regulated voltages
  • operates from positive or negative 12Vdc

The Q system of switching kits allows for direct random access from any system voice to any other voice. The ‘voice’ of a guitar rig might be the combination of the preamp channel plus reverb plus other effects. Each time you add one new feature or function, the number of combinations and thus the number of voices are multiplied. For example, a two-channel preamp obviously only has two voices. Add reverb and now there are four voices; add an effects loop and there are eight voices; add a third preamp channel and there are twelve voices.

Combine Q-LATCH with our Q-SW push-button to have a modern front-panel interface for up to four selections. Add Q-LED for a glowing indication of what has been selected, or mount the LEDs individually with LED mounting hardware.

Combine Q-LATCH with our Q-FSW foot-switch to create a sturdy interface for foot-actuated switches. The Switchcraft elements used here also make nice panel switches. Use a six-wire cable and connector to wire this to the amp.

Q-LATCH can be combined with our Q-RLY relay controller, Q-SR single-relay controller, Q-SF jfet controller and/or Q-FET series switching jfet shunt, in any quantity to control jfets, relays, voice LEDs and function LEDs. In such a system, Q-LATCH can be located inside the amp chassis or in a remote position. With Q-LATCH mounted in a remote foot-switch, the voice LED driver on the Q-FET and/or Q-RLY provide LEDs on the front panel of the amp.

Two or more Q-LATCHes can be wired in remote locations with another Q-LATCH inside the amp. The internal Q-LATCH provides front-panel control, where the remotes may be two foot-switches. Two-way communication ability means that hitting a button on one control panel changes the status indication on all the panels. Such sophistication is rarely offered in production foot controllers or even system controllers.

When more than four voices are to be accessed, Q-LATCHes can be ganged “sideways” using the LNK connection and lifting one resistor on each added Q-LATCH. This allows the first Q-LATCH to set the default and for all of the Q-LATCHes to interact as required.

Q-LATCH is quick to assemble with its high-quality PCB and kit notes.

Available configurations:

Standard DIY Kit (Q-LATCH-COMP) – requires assembly; includes notes.
Built Kit (Q-LATCH-BLT) – PCB is pre-assembled; includes notes.

PCB size: 3.7 x 2″, 94 x 51mm

For more information:
– see our page, About Our Switching Kits
– download our informative PDF: London Power Switching Kits Selection & Application (135 kB, 22 pages)