Acoustic Image Double Bass Amp – Contra S4 Combo


This is a legacy listing of the Acoustic Image Contra S4 combo amp, they’ve recently discontinued this item.

Going forward, Acoustic Image will be offering bass amplifier “combos” made up of their full range of amps plus their unique Upshot, DoubleShot and new Coda cylindrical cabinets! More info to follow.


The Acoustic Image Double Bass Amp Contra S4 Upright Bass Combo is the double bass amp combo of choice for Upton Bass.

The Acoustic Image Double Bass Amp Contra S4 Upright Bass Combo provides transparent, powerful, and accurate sound reproduction across the full frequency spectrum so that your sound comes through with all its strength and clarity.

Accurate reproduction of your musicianship should be the standard. However, getting great sound on stage with a bass pick up and a microphone is notoriously difficult. Your bass has great tone and your bass pickup does the job getting all of it, but this is irrelevant without a great bass amp to bring your sound your audience. Enter the Acoustic Image Double Bass Amp Contra S4 Upright Bass Combo!

Power, flexibility, and sonic performance are difficult to find in a portable amp, but the Contra Double Bass amp has all of this at a reasonable price. The Contra essentially disappears on stage, radiating omnidirectional sound and highlighting your performance – not your equipment. We call this “musical amplification.”


  • Balanced, high fidelity sound
  • Two-way sealed speaker system
  • 10″ downfiring woofer
  • 5″ extended range driver
  • Lightweight (22 lbs) molded polymer enclosure
  • One channel preamp, no effects
  • Three-band EQ preamp section
  • Combo jack input (either 1/4 in or XLR)
  • Phantom power on XLR input
  • Input and master level controls
  • Effects loop with return level control
  • Switchable Low Cut or Notch filter
  • Balanced direct out with ground lift
  • Mute switch and Pre/Post EQ for direct out
  • 300 Watt switch mode power amplifier, internally limited
  • Automatically switched dual voltage operation (100-115V/220-240V)
  • Comes with a fitted slip cover with cord storage pocket and shoulder strap

All AI amps are ordered when you order and typically have a 1 to 2 week lead time.  AI assembles all amps by hand and we’ve found that ordering them as we need them makes sure the most current product ships out to you!

Upton Bass String Instrument Co. specializes in building award-winning custom double basses and offers accessories or the double bass. Upton Bass also services all instruments and bows of the violin family with world class restoration and repair, to view our online restoration portfolio visit

Upton Bass is ready to offer advice and answer any questions regarding double basses or related bass topics. Please contact UB at or call the shop at +1 (860) 535-9399. Hours of operation Tuesday through Saturday 10am – 6pm. The Workshop (The Barn) and showroom are located in Mystic, Connecticut conveniently between Boston and NYC.


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