Keeley KBASS-U Bassist Compressor Pedal
Keeley KBASS-U Bassist Compressor Pedal
Product images are provided for reference and may not represent the exact model, configuration, or included components.

At A Glance

Voltage Input
9V
Current Draw
50mA
Input Impedance
1 MΩ
Output Impedance
100 Ω
Output Voltage Gain
+30dB Boost
Bandwidth
> 20kHz
Total Harmonic Distortion
0.1%
Noise
-95dBV
Threshold Indicator
Dual LED
Description

Keeley positioned the KBASS-U Bassist Compressor as a studio-grade VCA compressor in stomp-box format, designed specifically to address the demands of bass guitar signals, including compatibility with active preamps and line-level inputs. It was built around the THAT Corporation 4320 integrated circuit, a component associated with high-fidelity dynamics processing.

The circuit employs Voltage Controlled Amplifiers, an on-board true-RMS detector, and high-performance op-amps. Three primary controls — Threshold, Compression Ratio, and Gain — govern the unit's behaviour. The Threshold control sets the signal level at which compression engages; the Compression Ratio control adjusts the degree of gain reduction above that threshold, spanning from a 1:1 bypass-style setting through soft compression ratios to hard limiting; and the Gain control provides up to 30 dB of output boost. A dual-LED Threshold Indicator gives visual feedback on signal activity. The pedal operates on 9V DC at 50mA, presents a 1 MΩ input impedance and 100 Ω output impedance, and maintains a bandwidth exceeding 20 kHz with a total harmonic distortion figure of 0.1% and a noise floor of −95 dBV.

Owners requiring assistance with calibration, signal chain integration, or internal maintenance should consult a qualified electronics technician familiar with effects pedal circuitry.

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