Audio Damage has released Pulsemodulator as a free download for Mac and PC.

Description:

PulseModulator is a model of an extremely rare (and exceedingly strange) tremolo pedal from the 70s. Three LFOs effect the VCA at the same time, and the whole mess goes through a distortion circuit, resulting in strange modulating pulses of sound.

Audio Damage added tempo sync to the individual LFOs to make it more useful in a modern DAW environment.

Controls:

• Pulse Speed: These three knobs control the rate of the individual LFOs. If the sync switch for an LFO is engaged (the “1″, “2″, and “3″ switches on the bottom) that LFO will be synchronized to host tempo and the knob will select different tempo divisions.
• Pulse Depth: Perhaps unsurprisingly, these three knobs control the depth of the individual LFOs. That is to say, they control how much each LFO affects the dry signal.
• Boost Amount: This is labeled as it is on the real pedal. However, the label implies a boost circuit, but in fact it was more of a fuzz. We’ve modeled it as a fuzz but called it “Boost” as well.
• Pulse Shape: This controls the waveshape of all three LFOs.

Installation: For Windows, unzip PulseModulator.dll and place it in your VST plug-ins folder. For OS X, unzip the archive and place PulseModulator.VST in your VST folder and PulseModulator.component in your AU folder.

Download page