A-170 vintage edition contains two separate slew limiters, also known as portamento controllers or integrators. The first SL has just one joint control, which sets both rise and fall times (c. 0 ...10 sec). The second SL has separate controls for rise and fall times, and can therefore be used as a simple AR envelope generator. Over and above this, you can set the overall range for these parameters, with a three-position switch, as on the full ADSRs. Both slew limiters have two LEDs each, to show the state of the rising and falling voltages.