HPF-Pre Series 3 Mini

Over the years I've received many requests for a pedalboard-friendly HPF-Pre. The original HPF-Pre was designed for upright bass use, and I expected that it would usually sit on top of a small bass amp. But the HPF-Pre also caught on with electric bassists, and the electric world had already adopted the "pedal" form factor, with input and output jacks on the sides, and knobs on the top. Also, bassists who are already using other pedals are probably using a plug-in power supply rather than batteries.

Series 3 Mini is the same filter circuit as HPF-Pre Series 3, but with a bare minimum of features, and in a smaller box. Here's a rundown of its basic features:

• Adjustable "12+12" high pass filter, 35 to 140 Hz, described in the Series 3 documentation

• Passband gain 0 dB

• Requires external power supply, 9 to 30 Volts DC, very low current

• Input impedance 10 MegOhms, compatible with active, passive, and piezo pickups.

• No space for a battery

• Size: 50 x 100 mm, about 2 x 4 inches