Review: API TranZformer LX

Now that I’ve been running a recording studio for a couple years, I’ve become keenly aware of the heightened level of voodoo associated with certain gear brands.
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Now that I’ve been running a recording studio for a couple years, I’ve become keenly aware of the heightened level of voodoo associated with certain gear brands. If you think the average thread or Bass Player meetup gets geeky, it’s nothing compared to the discussion typical among recording engineers, and like us bass players, certain brands are universally associated with good tone. It makes sense, given that some gear’s mythical reputation is due to its historically integral role on the legendary recordings that are the very definition of “killer tone.” Near the top of the gaga-gear pyramid lies API, short for Automated Processes, Inc. The American answer to England’s Neve (another equally legendary studio gear brand), API consoles, EQs, and compressors have lent their muscular, rich, and tight sound to countless recordings we all know and love. The API TranZformer LX is API’s first purpose-built piece of bass gear, although that doesn’t mean its products haven’t been a part of thousands of bass signal chains on record.

At the heart of API gear—and a lot of high-end studio gear, generally—is a proprietary discrete operational amplifier (opamp). Opamps consist of bundles of components that, when packaged together, produce a remarkably versatile and high-performing amplifier, easily tasked to provide a dizzying array of functions in analog circuits. Most modern opamps come as a single chip in an “integrated circuit,” although boutique audio brands like API still produce opamps consisting of discrete components, sometimes packaged together in what looks like a small box. Much of the aforementioned voodoo that follows certain pieces of gear can be traced to these discrete opamps.

The above digression is to contextualize the fact that brands like API have reputational baggage, and that baggage is largely due to certain proprietary bits, like discrete opamps. It’d be easy for API to slap its hallowed brand on a bass pedal, stuff it with jellybean parts, and rake in the dough from our somewhat less finicky demographic, but I’m happy to report that the TranZformer LX is every bit the sexy pedal it ought to be.

The TranZformer is essentially a floor-mounted bass channel strip. It’s a preamp, not a DI. While it does have a balanced XLR output, it sends a line-level signal—don’t go connecting this to a mic pre, like you would with a DI. While simple, the API offers an effective combination of tone-enhancing features, whether live or in the studio. To me, the two obvious use-cases are in front of a power amp as part of a live rig, or in a studio with its output going straight to tape or to a digital system’s A/D converters.

The TranZformer LX is built to a standard that’s uncommon in the bass market. API uses three of its legendary 2520 discrete opamps and two 2510 line drivers, bespoke input and output transformers, and an EQ (based on API’s own 553 EQ) that utilizes custom-wound inductors for the low and midrange bands. The surface-mount board is beautifully laid out, and overall construction is top-shelf. While big for a stompbox, popping open the pedal reveals a thoughtful layout that’d be easy to repair, should the need arise.

The big question, obviously, is whether all the API’s fanciness combines for good tone. Does it ever! The TranZformer is uncommonly smooth and sophisticated-sounding. Its overall personality is balanced and full, with a precise and tight bottom end that is authentically among the better I’ve heard in a bass preamp. The thoughtfully chosen EQ frequencies are further enhanced with the circuit’s musical and creamy sound. The one-knob compressor, based on API’s slightly eccentric 525 design, goes from subtle to aggressive, and makeup gain is built into the circuit, with the 6-position switch essentially controlling threshold. It’s not flexible, but it imparts delicious harmonic richness and control over a peaky sound.

Given the astronomical cost of most API gear, the luxurious components and construction on offer, and its unimpeachably great tone, at under $500 the TranZformer LX is a remarkably good deal for such a serious piece of gear. If you want a small taste of that sauce that makes studio nerds swoon, it’s a no-brainer.



TranZformer LX
Pros Super-sweet and sophisticated tone; good price, considering the quality on offer
Cons None
Bottom Line A worthy member of the legendary API family, the TranZformer LX is a carefully designed piece of serious studio gear disguised as a stompbox.


Input ¼"
Input impedance 500kΩ
Outputs ¼" unbalanced, variable gain; XLR balanced, line level
EQ ±16dB @ 100Hz, 400Hz, 2kHz
Compressor One-knob, 6-position circuit with 2:1–20:1 ratio, depending on setting
Power 18 volts @ 250mA, adapter included

Made in USA