SDD-320 Dimension D vs DC-2. What's the deal?

[jdjk7]

Looking for those with more esoteric knowledge than me to help me answer a couple of questions about these two effects.

First: What's the appreciable tonal difference between the two? I've listened to demos of particularly the DC-2w with its Standard and SDD-320 mode, but it's been difficult to come to a conclusion based on that, often because the demos just don't tend to be super good.

Secondly, why did they use buttons? Well, let's say we know the DC-2 used buttons because the SDD-320 did. But why did the SDD-320 use buttons? I've heard different theories regarding Roland's motivation behind this, but nothing more than guessing. Was it because pots wouldn't fit in the enclosure? Cost saving on an expensive circuit? Because Roland wanted to make the effect deliberately simple, or to distinguish it from other effects? One guy speculated that it was a technical issue where only certain settings were usable, but if a pedal like the Fromel Seraph Deluxe is any indication, knobs can go on a Dimension-style pedal without much issue.

 

[bassbrad]

IIRC the original SDD320 was one of those happy discoveries (mistakes) in the lab of sonic research that became something useful like the fuzz effect or the aural exciter. These are described as chorus but there is no motion as associated with what we normally consider a modulation effect - the effects are more spatial and ambient in the realm of the stereoscopic field. Originally a studio rack effect advances in electronics allowed it to be brought out in pedal form. There is not speed or width so no need for those type of controls. The 4 buttons offer a number of combinations of fixed chorus colors usually engineers or players find the combination that works best with their mix, setup or preference.

Roland Dimension D SDD-320 Vintage Analog Stereo Chorus
https://www.boss.info/us/products/dc-2w/