Empirical Labs UBK Fatso


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This is the UBK-modified version of the Fatso, fine-tuned by Gregory Scott to his specification. For details of the modifications, and to understand the differences between the two versions, read the review on Tape Op or check the Kush video below


Below is my description of the Fatso, slightly edited to reflect changes in the UBK version:

The Fatso in this auction is the UBK-modified version of the Fatso which has some differences to the Empirical Labs version. It takes compression, harmonic generation & tape simulation to a new level.

The Fatso has seven compression styles, eight levels of warmth and a switchable transformer. These give hundreds of basic combinations, all of which are responsive to input & output gain settings

The UBK Fatso is more effective as a straight compressor / limiter than the original. It has three new compressor presets: Splat, Smooth and Glue, plus Spank which is brought over from the original version. Various combinations of the four basic presets are available. Compression reacts really nicely to varying input levels. Unity gain in bypass is approximately input 5.5, output 5.5 so there’s plenty of opportunity to overdrive the input & push the compressor harder.

Warmth is subtle on sources that are already harmonically complex, such as drums, but more noticeable on purer sounds. As with the compression side, there’s plenty of control range available and warmth can be pushed to generate quite extreme effects. In conjunction with the spank setting in the compressor it’s possible to generate full-on drum squashing with lots of movement but without the obnoxious high-end distortion some devices create when provoked

Overall, I found the Fatso to be smooth sounding and hugely appealing. It manages to be controlled but wild at the same time. It’s hard to wrong-foot it and create something that sounds like a mess but I’m sure it’s possible if you work at it!

I have to hand it to Dave Derr – the Fatso takes the Distressor and builds on it to create another unique, must-have piece of outboard gear. This UBK-modified version of the Fatso adds another dimension to the package and has resulted in rave reviews

Unlike the Distressor, the Fatso has two separate channels with a stereo link function so is ready for duties on the Stereo Mix Bus

Re UBK Fatso

“I wholeheartedly recommend the UBK FATSO, whether as (your) first dynamics processor or as the tenth. It sounds fantastic in many different applications — you can use it transparently or you can use it to add a fistful of character — and on top of that, it still gives you that FATSO analog magic!”

Re Empirical Labs Fatso

“In a word, the FATSO is a very good answer to what a lot of people loathe about digital recording. It smooths out the sharp, brittle edges to exactly the extent you choose, and fills in the hairline cracks just right. I use one on almost every mix I do. I could easily use one and quite possibly two more.” – George Massenburg

“People used to have to hunt for old, expensive gear to get the kind of sounds that the FATSO gives me.” – Ed Cherney

“The winner of the highly-coveted I’m Going to Write a Check Right After the Show award was picked up by Empirical Labs for their FATSO processor. You too can add girth, breadth and depth to your masters, and it sounds soooo fine” – Craig Anderton

“One additional point I want to make. Although the FATSO is marketed as an analog tape emulator, its uses are not limited to digital recording. Its various effects have a wide enough range (subtle, musical, extreme) that you may find it essential even if you are an analog- snob with nary a plan to record digitally” – Tape Op Review

“Let me first start off by saying that the FATSO was my single biggest game changer out of all my gear… The FATSO does exactly what it’s advertised to do and it sounds amazing doing it. It makes the signal huge, adds glue and takes away harsh frequencies”

Inputs and Outputs are balanced on XLR connectors and jack sockets. Each channel has a TRS jack insert and there’s an external link facility to allow multiple Fatsos to be linked. Compression is displayed on a horizontal LED ladder meter in a very similar way to the Distressor and there’s a similar display to show warmth. Power input is 110 / 220 Volt (internally switchable like the Distressor) with a standard IEC power socket

Standard rack-mounting 1U device

UBK Fatso

Product Page


Kush Audio video


Gearslutz thread


Gearslutz review


Fatso EL7X

Product page


Tape Op Review (old Fatso Junior)


Gearslutz Reviews (old Fatso Junior)


Mix Review (old Fatso Junior)


Youtube 2-Minute Review


Youtube 2-Minute Tones Fatso


Youtube Fatso demo



In excellent, used condition. There's a tiny bit of rack rash but otherwise the front panel is unmarked. The pots & switches have been cleaned & lubricated. Tested & working 100% and the Fatso sounds fantastic! UK, US or Euro power cable supplied on request. Photos are of the item in this auction

Vintage gear All vintage gear will have case scratches and marks. It may also have, or develop, noisy pots and switches. I make my descriptions as accurate as possible and note any existing defects. I test each item before shipping, and and supply a test sheet for it, but please understand that vintage gear will not be perfect and adjust your expectations accordingly

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