Our recreation of the vintage EHX Small Stone V2 loaded with

extra features to expand its palette while retaining the legendary sounds of the original. 

Features of Gallstone

• True Bypass Operational Transconductance Amplifiers (OTA) phaser
• 9v DC operation 2.1mm Boss style negative tip jack.
• 2/4 stage phase pushbutton switch pressing in button (red led) indicates 4 stage mode which is the stock original.(2 stage phasing indicated by blue led)
• Mix, feedback, rate controls 
• Level control corrects the volume drop of the original.
• Incorporating new Expand control which switches in an extra secret bit of additional circuitry into the mix. Designed to make things sound a little trippier, much like its designer. (Tuned 2 stage high "Q" all pass filter for those keeping up with all the technical details) 
• LED LFO indicator
• Voice pushbutton allows to switch between two different feedback network versions of the variants.
• Width control (8 way rotary switch) - the original circuit had a 2 way switch called Color. This switch had 2 width position settings. Color "On" position equates to position 8 and the feedback control at maximum. Color "Off" position of the original is the same as the width control being in position 5 and feedback turned fully off. Seperating the functions of the color switch into seperate controls allows the original settings to be selected easily, however now many more possibilities are available. As the width control is turned down the frequncy of the waveform increases, while the amplitude decrease. 
• Range switch - up position is standard, down allows super slow LFO sweeps.
• Please note: When first powering up the pedal, especially in "slow" range mode, the ciruit may take a few seconds to charge up before it functions. This is expected behaviour.
• 1590B enclosure size 
• Current draw 80mA. 

Big Thanks to Scruffie for his assistance in this project.

Without his input, this pedal would not had come into fruition :)