QRK-VX - Voice Selection Expander


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 QRK-VX is required when more than four system "voices" must be controlled in a guitar rig, but where the user interface is remote.

  • up to four incoming voice control lines
  • up to four output function control lines
  • can use DIPs for programming (order up to four QRK-DIP)
  • voice LED driver(4 LEDs)
  • 12Vdc required if LED driver is used

In a guitar system, the combination of preamp channels, effects, reverb, etc comprise the "voices" of the system. QRK-LATCH provides direct random access to those voices, but only up to a choice of 1-of-4. Adding more QRK-LATCHs allows the remote foot switch to be expanded, but at the amp end those extra voice control lines must be interfaced with relays, jfets and other devices. Such an interface can be accomplished by adding more QRK-RLY and QRK-FET control boards, but this is unnecesary in most applications. Rather, it is typical that a few functions must be accessed by a multiplicity of inputs. QRK-VX expands the number of voices that can control or access a given function in the amp or system when QRK-LATCHs are not present at the amp end..

Each of the four control blocks within QRK-FET and QRK-RLY has an XF pad, "expand function", where a fly lead can be soldered linking from the output of QRK-VX so that up to eight voices can access the given function. Add another QRK-LATCH at the remote foot switch and another QRK-VX in the amp for up to twelve voices accessing each function.

The incoming control lines typically correspond to "voices" of a guitar system, and QRK-VX has an onboard voice LED drive circuit. This is useful when the QRK-LATCH voice selector is wired in a remote location: the QRK-VX provides local annunciation of the voice selected while QRK-LATCH provides the same for the remote position.

Of course, QRK-VX can be used independently from the other QRK cards in creative fashion to interface custom circuit requirements.

Assembly of QRK-VX is quick and easy with the high-quality PCB and kit notes. The mounting holes are designed to line up with those in QRK-LATCH, QRK-RLY and QRK-FET so that the boards can be stacked if required.

QRK-VX is programmed by soldering jumpers where the DIP switches would otherwise go, if QRK-DIP is not used.There are four XF output pads, so four positions for DIP switches to access up to four functions.

The stock LEDs are round 3mm green standard brightness.Kit requires assembly.

PCB size: 3 x 1", 76 x 25mm

See also:

QRK-DIP - 4-way DIP switch

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About London Power

London Power was founded in 1990 by Kevin O'Connor, after two decades of research into innovative audio amplification techniques. Kevin is an audio designer, author and speaker, known for his proprietary methodology called Power Scaling, and for his eleven books on audio subjects. Whether you seek amps, kits or information, you'll find useful answers here on not just the "how" but the "why" of audio amplifier design. Please enjoy the information on this site, and don't hesitate to contact us with questions.

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