The 1001RB is the original iteration of GK's flagship solid-state bass head — the one that set the template for everything that followed. Built around an analog power amp and high-current power supply, it delivers 540 watts into four ohms through the main amp with a separate 50-watt horn amplifier for bi-amp operation. The bi-amp design is what distinguishes the GK RB series from the competition: an active electronic crossover splits the signal at 5kHz, sending the full-range signal to the woofer amp while routing only the high frequencies to the horn amp. That means you can push the woofer amp into the rails for GK's characteristic growl without overdriving the tweeter — a genuinely useful feature for players who want grit without sacrificing high-end clarity. Four-band active EQ, contour and presence voicing filters, a 4/5-string voicing switch, the GIVE boost circuit, effects loop, tuner output with mute, and a balanced XLR DI with level, ground lift, and pre/post switching round out a well-specified head that has remained a go-to for working bassists for decades.
This unit is in good condition and fully functional throughout. Cosmetic wear is consistent with normal use. Photos show the condition accurately.
- Make: Gallien-Krueger
- Model: 1001RB (original series)
- Type: solid-state bass amplifier head, bi-amp
- Power output: 540W at 4 ohms (main amp), 50W horn amp
- EQ: 4-band active — bass (+10dB @ 60Hz), lo-mid (+6/-10dB @ 250Hz), hi-mid (+6/-10dB @ 1kHz), treble (+14dB @ 7kHz)
- Voicing filters: contour, presence, 4/5-string switch
- Boost: GIVE (Gate Induced Valve Effect)
- Effects loop: yes
- Tuner output: yes, with mute
- DI: balanced XLR, level control, ground lift, pre/post switch
- Speaker outputs: 2 x 1/4", 2 x Speakon
- Crossover: triple-pole constant voltage at 5kHz
- Noise: -90dB A-weighted
- Rack spaces: 2U
- Dimensions: 19" x 8" x 3.5"
- Weight: approximately 22 lbs
- Modifications: none
- Includes: none
Ships carefully packed and insured for full value.
International buyers are welcome — please contact us for a shipping quote before purchasing.
About Mill River Music
Mill River Music is an independent, human-powered music shop located in downtown Northampton, MA, run by a team of players, enthusiasts, and certified repair technicians. Every piece of used gear we sell is personally inspected, tested, and set up before it ships — we don't list it until we'd be happy to play it ourselves.
As Martin and Taylor certified techs, we hold our guitar work to a high standard, and we're committed to full transparency about the condition of everything we sell. No surprises.
When you buy from Mill River, you're supporting an independent local business that genuinely cares — about gear, about players, and about doing things right. We're here every step of the way. Reach out anytime.
