The Amptweaker Fat Metal Pro II is a hi-gain preamp pedal for recording or live performance, designed by Amptweaker for the low-end distortion used in styles like black metal and doom metal1. The company describes it as the work of "iconic high-gain amp guru James Brown," the designer behind the brand1. It is all analog, with what Amptweaker calls "none of the latency associated with digital technology"1.
Amptweaker's product page listed the Fat Metal Pro II as out of stock as of May 20251. The original Fat Metal Pro was described as no longer made on That Pedal Show in June 20163.
Power: 9V or 18V
The pedal runs at 9V or 18V DC, and the choice changes how it responds: Amptweaker says to "run at 18V for more headroom or 9V for more drive & compression"1. Current draw is 39mA with a 9V adapter, and a power supply is not included1. At 39mA it is beyond what most pedalboard daisy-chain supplies deliver per output, so a dedicated supply output is the practical route.
Controls and loops
The pedal carries Gain, Tight and Volume controls1. Around the core circuit, Amptweaker built in three switching loops, which is unusual for a distortion pedal and shapes how it fits a rig:
- Global Loop: works when the pedal is on, which Amptweaker suggests is great for EQ or reverb1
- Boost Loop: works whenever the Boost switch is activated, for placing delay, reverb or solo effects where they suit a lead tone1
- Side Track: usable as an A/B switcher between amps, clean and dirty for example, or as an ancillary loop for additional effects when the Fat Metal Pro II is not active1
The DeFizzerator is built in as well1. Amptweaker names it as a feature without detailing its operation on the page, but in a pedal aimed at heavy low-end distortion it addresses the fizz that high-gain circuits can produce.
Fat Metal Pro II in the Amptweaker range
The Fat Metal Pro II sits alongside the Amptweaker Tight Metal Pro II in the company's metal-oriented preamp line, and the Amptweaker Big Rock Pro II covers a related role in the range2. For a wider view of where a preamp pedal fits a board, see Preamp Pedals, and for the distortion territory this pedal occupies, see Distortion Pedals.
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Questions
Is the Amptweaker Fat Metal Pro II all analog?
Yes. Amptweaker describes the Fat Metal Pro II as having all analog circuitry, with none of the latency associated with digital technology. It is a hi-gain preamp pedal intended for recording or live performance, and it runs on a 9V or 18V DC supply, drawing 39mA with a 9V adapter.
Does the Amptweaker Fat Metal Pro II come with a power supply?
No. Amptweaker lists the current draw as 39mA with a 9V adapter and notes that a power supply is not included. The pedal can run at 9V for more drive and compression, or at 18V for more headroom, so players choosing an 18V supply should confirm it suits the pedal's requirements.
What does the DeFizzerator do?
The DeFizzerator is a feature built into the Fat Metal Pro II. Amptweaker does not detail its operation on the product page beyond naming it as a built-in feature, but the pedal as a whole is designed for the low-end distortion used in styles like black metal and doom metal, where fizz control matters.
Where is the Amptweaker Fat Metal Pro II made?
The Fat Metal Pro II is made in the USA, according to Amptweaker's product page. The company also backs the pedal with a 5 year limited warranty.
Is the original Amptweaker Fat Metal Pro still made?
No. On That Pedal Show in June 2016, the Fat Metal Pro was described as no longer made. Its successor, the Fat Metal Pro II, is the current version, though Amptweaker's product page listed the II as out of stock as of May 2025.
Sources (3)
- Fat Metal Pro II, amptweaker.com, 2025-05-28
- Tight Metal, amptweaker.com, 2025-12-01
- Boss Metal Zone: Part 2 With Rabea Massaad, That Pedal Show, 2016-06-24
