Here’s a meat-and-potatoes freebie from Black Rooster.
“Built around a cascade of two constant-K filters the VHL-3C‘s analog counterpart – a sought-after processor from the early 1950s – comprises an entirely passive design with very musical and interactive pass filters. Offering 3 simple and intuitive controls, the VHL-3C allows you to effectively remove rumble, hum or harsh frequencies from your signals. Set both filter knobs to their extreme positions and you‘ll end up with a narrow telephone-line bandpass. „So what?“, you may wonder – Black Rooster Audio is giving away this goodie for FREE!”
This looks great, but the whole ‘installer’ thing for a single plug-in kinda blows.