Smartelectronix AnalogDelay

It consist in a delay unit followed by a 2nd order lowpass filter with saturation. The delay-time can evolve between 0 and max-delay which lets you be very accurate. You can also synchronise the delay to the tempo with different resolutions from 1/128 to 1 bar and control the way the delay-time is interpolated with the kind of interpolation and the time-constant.

http://mdsp.smartelectronix.com/analog-delay/