Mad Professor releases Simble MkII overdrive with revised circuit

January 1, 2025 · 3 sources

Mad Professor released the Simble MkII overdrive in 2025, with a circuit revised by the original Simble designer, Lassi Ukkonen¹². Preorders opened by March 31, 2025², and Gearnews reported the official launch on June 3, 2025³.

The MkII keeps the original's four controls: Level for output, Sensitivity for distortion and compression, Accent for pick attack and brightness before the signal is overdriven, and Contour for output brightness¹. Delicious Audio describes the arrangement as letting players EQ the signal before or after the overdrive, as on a Dumble amplifier¹. Guitar Pedal X lists Contour as a tone control that is unity at noon², and Gearnews describes it as neutral at noon and says it was cleaned up from the original after some players found it muddy with certain guitars³.

The revised circuit is said to produce a more open sound, more headroom and overall brightness¹². Gearnews reports that the Sensitivity control shows the effect of the new design, which it says was tweaked to improve string clarity even at maximum drive³. Guitar Pedal X reports a new red enclosure with stronger Mad Professor branding, replacing the original wood-finish design².

Mad Professor's published specifications for the Simble list a current draw of about 10 mA at 9V DC, an input impedance of 430 kohm, an output impedance of 50 kohm, a supply range of 9-12V, silent true bypass, and power from a 6F22 9V battery or a DC eliminator with a 2.1 mm plug, center negative¹.

Prices reported at launch differ. Guitar Pedal X gave 199 euros, $215 and 165 pounds at preorder². Gearnews cited an official price of 199 euros and listed $177.00, 159.00 pounds and 189.00 euros at Thomann³. No US list price in dollars was confirmed by Mad Professor in either report.