Mad Professor Forest Green Compressor

The Mad Professor Forest Green Compressor (FGC) is a compressor and sustainer pedal for guitar and bass, made by Mad Professor. It is designed, in the maker's words, "to meet the highest standards of guitar and bass compression," and it splits its job across two modes: a Compressor mode for standard compression and a Sustain mode that amplifies the decay and weaker parts of a note while preserving the attack¹. The maker describes it as "a very transparent compressor with natural compression"¹.

The circuit has a family history. Ovnilab's review notes that the pedal is based on the BJFE Pine Green compressor, and that the Forest Green adds a mode switch the original did not have².

The controls and the two modes

The front panel is deliberately small: three knobs (Level, Compr, Tone) and one switch that selects between Compressor and Sustain³¹.

The two modes are really two compression ratios. Ovnilab's reviewer explains that the switch selects between a very high ratio, labeled "compressor," and a very low ratio, labeled "sustain"². In their testing, "With the switch set to 'sustain', the entire sweep of the Compr knob is useful, just adding different amounts of light-to-moderate compression"².

A review at guitargearreviews.com found the Tone control useful in practice: "The Tone knob provides a functional EQ, brightening or rounding off the top end as required"³.

What the maker says each mode sounds like

Mad Professor's own demo material describes the two characters:

• In Sustain mode, "you can get a very dynamic, touch sensitive tone with a long sustain. Here the attack is not lost, making the pedal suitable even for blues players and works great with slide playing"¹.
• In Compressor mode, the pedal delivers standard compression for evening out levels⁴.

A demo video from the Mad Professor Amplification channel, with Marko Karhu playing various guitars through the pedal, covers both modes and the maker's description of the FGC as a transparent compressor with natural compression¹.

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Power and bypass

The FGC can run on a 9V or 18V DC power supply, as well as on a 9V battery³. Ovnilab's reviewer describes the pedal as running on standard Boss-type 9V DC and confirms the footswitch is true bypass, so the signal passes around the circuit when the pedal is off².

History and the hand-wired version

The Forest Green Compressor is based on the BJFE Pine Green compressor, with the mode switch added as an improvement over the original².

Ovnilab's review notes there are two versions of the pedal: a PCB (printed circuit board) version and a "hand wired" version, in which all the parts are wired directly together². The hand-wired model is covered on its own page: the Mad Professor Hand-Wired Forest Green Compressor.

What reviewers and players say

Ovnilab's independent review covers the circuit's lineage, the two-ratio switch and the true-bypass switching². At guitargearreviews.com, Cal Whitaker calls the Forest Green Compressor Factory "a dependable choice" and summarizes player impressions as highlighting "ultra-low noise operation, transparent compression, and sturdy build as standout traits, with many noting the pedal's ability to enhance both subtle and aggressive playing"³.

The same review notes the pedal's streamlined control set of Level, Tone and Compression with the dual-mode switch³, which matches the maker's own description of the design³.

For more on the category generally, see the compressor pedals page.

Videos

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Questions