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HH – XR Flex Resonant Filter System

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This product has been discontinued.


Complete Standard System featuring our XR Flex Series extended-range pickups including 2 XR Quad pickups (H-H) for 6, 7, and 8 string instruments. In addition to the pickups, the system includes a 5-way switch, Active Volume, Resonant Filter, Output Jack, 9V battery clip and all necessary cables and hardware.

The XR Quad Flex pickups are full sized, low-impedance humbuckers with full frequency response. Features 4 side-wound coils, neodymium magnets and a choice of Standard or Soapbar baseplate. Available for 6, 7 and 8 strings.  Learn more →

The Resonant Filter allows you to dial in the characteristics of virtually any pickup with two high quality dual-ganged Bourns® potentiometers. The Resonant Filter offers independent control of the cutoff-frequency and resonance (Q). The Resonant Filter is a single opamp VCVS second-order low-pass filter design with variable frequency, and variable resonance with constant gain compensation. The circuit utilizes the audiophile grade OPA209, a modern precision operational amplifier with very low voltage noise density of 2.2nV/√Hz, and a rail-to-rail output swing with a supply voltage from 4.5 to 36 volts  maximizing the dynamic range. Learn more →
Cycfi XR Data Sheet →
Flex Installation Guide →
Options and Configurations →
Shipping & Returns →

H-H Quad Flex Pickups

Resonant Filter System Support

Additional information


XR Quad Flex 6 (Standard), XR Quad Flex 7 (Standard), XR Quad Flex 8 (Standard), XR Quad Flex 7 (Soapbar), XR Quad Flex 8 (Soapbar)