Shruthi XT

Back in the early 2010s, this synth kicked off a DIY revolution with its open-source design, letting builders swap in different analog filters for endless tonal tweaks—think classic Roland warmth or gritty Polivoks bite.

The heart is a pair of digital oscillators dishing out wavetables, phase distortion, FM, PWM, sync, and even supersaw waveshapes from tri and saw to noise and sampled transients, paired with a swappable analog filter offering lowpass, highpass, bandpass, notch, allpass, and 24dB/oct modes like the SSM2164-based 4-pole mission or Polivoks clone. Two ADSR envelopes and LFOs (with tri, saw, square, sample & hold, and wavetable options) feed a 10-slot mod matrix, plus a 16-step sequencer/arpeggiator you can jam into action with a dedicated button. Hands-on control comes via 16 knobs, a clickable encoder, switches, backlit LCD display, and global volume knob on its compact desktop panel, with MIDI in/out/thru, CV/gate, mono audio I/O on 3.5mm jacks, and an on/off switch.

Owners love its lo-fi charm and versatility for everything from CZ-style plucks to beefy basses, though some note the monophonic limit and DIY quirks demand a bit of patience.