The Caveman Audio ACC1 is a two-rack-space acoustic guitar preamp and D.I. rack unit, described by the maker as "The ACC1 Acoustic Channel, our flagship." Its stated job is to keep the character of an acoustic guitar intact when the instrument is amplified through a PA, and it carries a transformer-balanced XLR D.I. output for exactly that. It was designed by Steen Skrydstrup, who traces its lineage to a custom unit built for the Scorpions' MTV Unplugged Tour in 2014.1
Where it came from
The ACC1 is a scaled-down version of the Acoustic Guitar Unit Caveman Audio developed for the Scorpions' MTV Unplugged Tour in 2014. Skrydstrup explains the intent in his own words: "It took me quite some time to perfect the sound and the playing aspects of the ACC1 Acoustic Preamp System." The maker's description of what it does is equally direct: "The ACC1 has one job: To maintain every nuance of your acoustic guitar sound, making it spring to life even when amplified through a PA system."1
Inputs, outputs and the footswitch
The unit is built around balanced connections on both sides of its signal path, which suits a rack setup where a wireless system feeds the preamp and a long cable runs to the front-of-house console.1
- Input: transformer-balanced, gold-plated Neutrik XLR radio/wireless input1
- Output: transformer-balanced, gold-plated Neutrik XLR D.I. output1
- Remote foot switch: Boost ON/OFF, Attack 1/Attack 2, and Mute1
The remote footswitch covers the three things an acoustic player is most likely to change on stage: a boost for a solo, a switch between two attack settings, and a mute between songs.1
Specifications
| Specification | Value |
|---|---|
| Format | 2U 19-inch rack unit1 |
| Dimensions | 19" x 2U x 350 mm (W x H x D)1 |
| Weight | 5 kg / 11 lbs1 |
| Input impedance | 5MΩ1 |
| Output load, D.I. | 2kΩ or more1 |
| Power | 100-240VAC 47-63Hz1 |
| Enclosure | Road-ready zinc-plated steel1 |
| Warranty | 10 Year Warranty1 |
The 5MΩ input impedance is high enough to sit comfortably with piezo pickups, which can lose their low end and turn brittle when they see a lower impedance. The universal power range means the unit runs on mains power anywhere without a separate supply.1
The ACC1 is a rack unit that runs on 100-240VAC mains power, so it is not a battery-powered or pedalboard device.1
How it sits among the alternatives
Most acoustic preamp and D.I. products players compare are pedals rather than rack units, such as the Radial Tonebone PZ-Pre, the Boss AD-10 Acoustic Preamp or the Pete Cornish Acoustic Preamp/DI/Mute. The ACC1's 2U rack format, balanced XLR input for a wireless system, and remote footswitch put it in a different category: a fixed stage or rack setup rather than a floorboard. Caveman Audio also makes pedal-format units, including the Caveman Audio AP1 and Caveman Audio AP1 Compact, for players who need the same idea in a smaller box. For a wider view of the category, see Acoustic Pedals.1
Videos
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Questions
How many rack spaces does the Caveman Audio ACC1 take?
The ACC1 is a compact 2U 19-inch rack unit, so it takes two rack spaces in a standard rack. Its dimensions are 19 inches wide by 2U high by 350 mm deep, and it weighs 5 kg, about 11 lbs, in a zinc-plated steel enclosure the maker describes as road-ready.
What does the ACC1 remote footswitch control?
The ACC1's remote foot switch gives hands-free control of Boost ON/OFF, switching between Attack 1 and Attack 2, and Mute. That covers the functions a player is most likely to change mid-song, such as kicking in a boost for a solo or muting between numbers.
Does the ACC1 have a balanced XLR output?
Yes. The ACC1 has a transformer-balanced, gold-plated Neutrik XLR D.I. output intended to feed a PA system directly. It also has a matching transformer-balanced, gold-plated Neutrik XLR input for a radio or wireless system.
What is the input impedance of the Caveman ACC1?
The ACC1's input impedance is 5 megohms, a high figure that keeps piezo and other undersaddle pickups from sounding thin or quacky. The D.I. output is specified for a load of 2 kilohms or more.
Who designed the Caveman Audio ACC1?
The ACC1 was designed by Steen Skrydstrup of Caveman Audio, who describes it as the company's flagship acoustic channel. He says it took him considerable time to perfect both the sound and the playing aspects of the preamp system.
Sources (1)
- ACC1 acoustic channel, Caveman Audio, 2026-04-13
