Empirical Labs FATSO--Full Analog Tape Simulator and Optimizer

Empirical Labs FATSO
Full Analog Tape Simulator and Optimizer

by Bob Buontempo

The FATSO acronym stands for Full Analog Tape Simulator and Optimizer. However, that only partially describes the effects and features offered by this unique piece of audio gear.

Designed by Dave Derr, FATSO is the latest product offering from his company, Empirical Labs, manufacturers of the well-known EL-8 Distressor, a favorite of many producers and engineers. It’s my first choice in several situations that call for the use of a compressor.

After months of hearing rumors floating around the industry concerning FATSO, it was with great anticipation that I received one of the first production units for review.

The Basics

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The EL-7, as the FATSO has been designated, is a 2-channel, digitally controlled, analog signal processor, capable of stereo or dual-mono operation. The front panel has four large, calibrated knobs that go up to 10—not quite Spinal Tap, but very close. Two of the gray knobs are used for Input Level and two for Output Level control. Three buttons per channel (the Compression Selector switch, the Warmth/Link switch and the Tranny/Bypass switch) and a host of LEDs for metering and status indication completes the package.

Inputs and outputs are via XLR or 1/4-inch TRS jacks, with the XLRs differentially balanced on the inputs and outputs and the 1/4-inch jacks balanced on the inputs as well. Pin 2 is wired “hot” on the XLRs and is user-changeable to Pin 3 from inside the unit. The owner’s manual makes a point of stressing that the unused pin of a single-ended XLR output cable should be “floated” rather than tied to ground to prevent shorting out any of the output amps. I checked with the factory about this, as many potential owners of the unit may use off-the-shelf cabling for their wiring needs. In many instances, pre-wired XLR to 1/4-inch cables have the unused XLR pin tied to ground on the minus side. This is true especially if they are of the unbalanced, two-conductor, musical instrument-type. The manufacturer replied that this would only present a problem if a combination of XLR and 1/4-inch jacks were used simultaneously. In case of doubt, Empirical Labs offers optional (correctly configured) XLR to 1/4-inch adapter cables.

No digital inputs/outputs are provided, even though the targeted market is obviously the DAW, MDM and hard disk recording contingency. I thought about this for a while and decided it was a good thing. Because this is an analog processor, you’d eventually have to convert your digital signal to analog to use this unit, anyway. If Empirical Labs had included an AES or S/PDIF provision, then not only would the price increase, but you’d be forced to use their converters, however good or bad they were, instead of the converters you already own and love. This way just saves you a decision and a step. If you don’t want to ever leave the digital domain, then this is probably not the unit for you at mixdown, but it certainly could be helpful during tracking sessions.

A Link/Sidechain input and individual channel inserts are also provided via 1/4-inch jacks. The power cord is the IEC-removable type, and an internal switch can change the operating voltage from 110 to 220 VAC.

Reprinted with permission from

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