The Stoned Marten LPG-ADSR Card for 208

Stoned Marten Card expand the 208 with an analog VC looping ADSR enveloppe, a Lo Pass Gate, a preamp and an output mixer.
The switches let you instantly turn on, off and mix various signals to trigger the ADSR and open the LPG.
You can shape and put life into your patches thanks to the CV inputs controlling each setting.
This opens up countless modulation variations.

It's an ideal companion for the VCS3 Card to add a full 3rd voice to your 208.

The Stoned Marten Card works with every 208 revision except the 208r rev1.

The Stoned Marten Card is available pre-built for 550 euros - VAT and shipping not included.
  Contact me to join the waiting list for a pre-built card or for more information.

The DIY PCB set is immediately available from

Users manual
Build notes

Many thanks to Todd Barton for the videos !



LED : monitors the ADSR output

    • Attack : sets the attack time
    • Decay : sets the decay time
    • Sustain : sets the sustain amplitude
    • Release : sets the release time

Black banana CV inputs - each with attenuator trimmer
    • Attack : controls the attack time
    • Decay : controls the decay time
    • Sustain : controls either the sustain amplitude or the pulse length
    • Release : controls the release time

Trigger source
    • Red banana : pulse input
    • Length pot : sets the input pulse length, it is to adapt the pulse length for best response to the various trigger and gate sources or to create variations in a sequence
    • Seq / puls switch : selects if the 208's pulse sequence switches or pulser triggers the envelope
    • Self switch : switch it to the right to enable self-retriggering
    • Self LED : monitors the retrig pulse
    • Self black banana : CV input to the retrig pulse delay
    • Self pot : sets the retrig pulse delay

Orange banana outputs
    • Out : ADSR CV output
    • Inv. out : ADSR CV inverted output
    • Switch : connects either the output or inverted output to the LPG level input


    • Left pot : sets the CV input amplitude
    • Right pot : sets the amplitude manually
    • LED : monitors the LPG opening
    • Black banana : CV input
    • Env / puls switch : selects if the 208's envelope or pulser controls the LPG level
    • Mode select
    • Switch : selects LPF combination or VCA mode
    • Black banana : mode CV input - with attenuator trimmer next to the switch
    • Internal ‘CV response’ trimmer : sets the LPG response to CV, adjust it according to your own 208 and preference
    • ‘active – passive’ mini slide switch : selects active or passive mixing of the CV sources


    • Signal in tinijax : signal input to the LPG
    • Gain switch : switch to adapt the preamp gain according to the incoming signal amplitude
    • Phase : switch tho the right (inv) position to invert the incoming signal phase

Output section

    • Channel C pot : sets the LPG output amplitude to the output mixer
    • Signal out : LPG and mixer output
    • Signal in : input to the mixer to patch one of the 208's signal outputs in order to have a single mixed signal of the 3 LPGs at the mixer output