Ampeg SCR-DI

The Ampeg SCR-DI is a bass preamp and DI pedal that puts a full Ampeg preamp, the classic Ampeg tone stack, and a Scrambler bass overdrive circuit in one floor unit¹². Ampeg describes the tone stack as offering "everything from plush B-15 to aggressive SVT grit," and the Scrambler section as letting you "dial in the distinctive grind of overdriven tubes"¹. It was announced at Winter NAMM in January 2015 and released in early 2015³⁴.

For a bassist, it works as three things at once: the always-on preamp and EQ that shapes your core tone into a power amp or PA, a DI box that sends your effected signal to front-of-house, and a switchable overdrive for grit. Guitar World's 2026 guide to the best bass preamp pedals names it the pick for Ampeg tone in that category⁵.

What it is and what it does

Ampeg positions the SCR-DI as a true Ampeg preamp rather than a pedal styled after one: the announcement called it "a true Ampeg preamp, with legacy preamp and tone stack circuits"³. The preamp feeds the classic Ampeg three-band EQ, and the Scrambler overdrive sits in the same box so you can add tube-style grind without a second pedal¹. The bottom left footswitch engages or disengages the Scrambler circuit, so the overdrive is switchable independently of the preamp⁶.

Bass Gear Magazine's reviewer, Phil Maneri, summed up the core unit in his December 2015 review:

He concluded that pro players should take it seriously overall, while criticizing the battery life, an internal pad jumper, and the Scrambler circuit itself⁶.

The controls: EQ, Ultra-Hi and Ultra-Lo, and the Scrambler

The tone-shaping controls are the classic Ampeg set: a three-band EQ plus the Ultra-Hi and Ultra-Lo filters that Ampeg has used on its amps for decades¹. Bass Gear Magazine measured what the two switches actually do⁶:

The Ultra-Lo is the interesting one for bass players: it lifts the very bottom while cutting the low mids at 500Hz, which thins out mud while adding weight, the same trick as the switch on Ampeg's SVT and B-15 amps. Guitar World's guide put the pair more bluntly, noting that "the addition of 'Ultra-Hi' and 'Ultra-Lo' switches allows you to get pretty stupid with the extremes of your tone"⁵⁶¹.

The Scrambler side is Ampeg's take on a bass overdrive, designed to add the grind of overdriven tubes without losing the low end¹. Premier Guitar reviewed the Scrambler circuit on its own when Ampeg released the pedal in early 2015⁴.

Outputs: XLR, 1/4", thru and headphones

The SCR-DI's I/O is what makes it a gigging tool rather than just a tone pedal. Ampeg announced it with "connection options perfect for driving any bass rig and feeding a bassist's effected signal right to front-of-house"³. The outputs break down as follows:

• XLR output: feeds your effected preamp and EQ tone straight to the PA or a recording interface³
• Thru output: an unaffected, instrument-level copy of your input signal, which Bass Gear Magazine noted suits parallel processing or running a tuner⁶
• Phones output: for headphone practice¹
• Aux input: for plugging in a track source¹

One detail matters for practice use: the aux input is mixed with your bass only at the headphone output, not at the main outputs, so backing tracks never reach the PA⁶. That makes the SCR-DI a self-contained practice rig as well as a live DI.

History: from the BA-series combo front end

Ampeg released the SCR-DI in early 2015⁴. Its US list price at the time was $279⁷. The pedal's circuit is an evolution of the front end used in the updated BA-series combos⁶.

The circuit has a traceable lineage. Bass Gear Magazine's review connects it directly to Ampeg's combo amps: "the SCR-DI is clearly an evolution of the front end used in those combos," referring to the updated BA-series combos⁶. So the pedal is essentially the preamp and EQ section of Ampeg's BA combos, plus the Scrambler overdrive, packaged for a pedalboard.

It is made in China for Loud Technologies Inc., the company behind the Ampeg brand, and carries a 1-year nontransferable warranty⁶.

Where it sits among bass preamp pedals

For a player who wants the Classic Ampeg tone stack, which Ampeg describes as offering "everything from plush B-15 to aggressive SVT grit"¹, plus the Ultra-Hi and Ultra-Lo switches and a built-in overdrive in one analog box, the SCR-DI covers preamp, DI and drive duties in a single unit. The Scrambler overdrive section lets you dial in what RockBoard's PedalPedia calls "the distinctive grind of overdriven tubes"¹⁶, engaged or disengaged from the bottom left footswitch¹⁶.

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