Description: Magic Smoke “Mankato” Voltage Controlled Filter / Low Frequency Oscillator / Slew Limiter
From the Magic Smoke website:
Designed by well known synth DIY guru Thomas Henry, the TH-201 is a low-pass VCF with some unusual operating modes. Magic Smoke will be producing printed circuit boards (PCBs) which can provide up to eight outputs. With the Resonance control turned all the way up, these filters will self-oscillate, operating as multi-phase LFOs or VCOs.
Both DC-coupled and AC-coupled inputs are available. The DC-coupled inputs allow the TH-201 to operate as a voltage-controlled lag processor (slew limiter). All outputs are buffered and have standard 1k impedance.
The Mankato covers a very wide frequency range — around 0.005Hz (200 seconds/cycle) to beyond 20kHz without range switches. Changing the timing capacitors can provide extended low frequency operation.
I purchased my Mankato used, assembled by someone else. It required a small repair. I replaced the coarse and fine tune frequency pots with high-quality Spectrol 149 cermet units. I also changed the input over to DC-coupling, enabling use as a slew limiter.