Detail 01
9–18 V operation
Running at 18 V provides increased headroom and fidelity, with less sagging than older RATs.
Product detailSKU #1500000012206
ProCoFAT RAT Distortion Guitar Effects Pedal
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Independent shopping perspective
The Korena take
ProCo’s FAT RAT takes the ’85 Whiteface Reissue RAT as its starting point and adds two selectable clipping paths, a Fat switch, and a socketed op-amp. Choose silicon clipping for the classic RAT circuit approach, or MOSFET/germanium clipping for a subtle upper-mid scoop and smoothing across the gain range. The Fat switch adds substantial bass while reducing highs, supporting bass guitar, lower tunings, and fuller low-gain overdrive settings. CTS controls provide an even sweep across Distortion, Filter, and Volume, and the pedal operates from 9 to 18 volts.
Strong match
Who this is for
- Switching between silicon and MOSFET/germanium clipping within one distortion pedal.
- Bass guitar, lower tunings, or low-gain overdrive settings using the Fat switch.
- Players who want solder-free changes to the socketed op-amp using compatible chips.
What matters in use
The specifications, translated
Catalog numbers tell only part of the story. These are the details most likely to change how this product feels, sounds, or fits into a setup.
Detail 02
CTS Distortion, Filter, and Volume pots
The controls are intended to sweep smoothly and evenly through their ranges.
Detail 03
2.01 x 2.24 x 3.39 inches; 0.51 weight
These are the pedal’s listed dimensions and weight.
Final check
Know before you order
- 01Choose your operating voltage within the supported 9–18 V range.
- 02For an op-amp swap, use a compatible chip in the socketed position.
Product questions
Before you decide
Straight answers to the questions shoppers most often ask about this product.
01What clipping options does the FAT RAT offer?
It switches between silicon clipping and a MOSFET/germanium clipping section.
02What does the Fat switch do?
It provides a significant bass boost and simultaneous high cut, intended for bass guitar, lower tunings, and fuller low-gain settings.
03Can the op-amp be changed without soldering?
Yes. The included OP07DP is socketed, and compatible chips can be swapped without soldering.
04Can the FAT RAT run at 18 volts?
Yes. It operates from 9 to 18 V; 18 V increases headroom and fidelity with less sagging than older RATs.
Reference
Full specifications
The complete catalog record, organized around the decisions musicians make when comparing gear.
2 detailsSize & weight
- Dimensions Wxhxd
- 2.01 inch x 2.24 inch x 3.39 inch
- Weight
- 0.51
