Stereo modulation.

[POTL]

I was looking into the BOSS DC-2W circuitry to understand how the stereo effects work and noticed that both delay chips have the same filtering, common LFO, basically everything around them is identical, except that one chip is shifted 180 degrees. As far as it is practical and justified, in comparison with the approach, MXR, TC, DOD, BOSS CE-3, one delay chip is used for years, and the second channel is inverted by 180 degrees at the output. The only excuse I see for the second chip is that they are slightly different from each other and not 100% identical, the delay time in theory can differ by one or more milliseconds, which should give a greater effect. but does it have real profit or is it done more for marketing?

[ElectricDruid]

No, it's completely different, definitely not just marketing.

The single BBD pseudo-stereo way gives you one "dry + delayed" signal, and one "dry - delayed" signal. It's the delayed signal that gets inverted.

The dual BBD method inverts the *LFO* instead. This means that as one BBD is going up, the other is coming down. The sonic effect of this is that the pitch shifts produced by the BBDs are always "balanced" - if one signal is a bit sharp, the other is a bit flat...and then they swap over! This hides the audible "wobbly" quality you get sometimes with chorus, and gives a smoother sound.

[POTL]

great, now everything is clearer about the real stereo. Thank you.

[Mark Hammer]

There's synchronous stereo and asynchronous.  The Magnatone amps that offer stereo vibrato also use a single LFO, and invert it to provide countersweep.  I whipped up a Magnavibe emulation of the Magnatone vibrato circuit, and was curious about stereo, so I built a second, with its own LFO.  I had some dual ganged pots that let me adjust speed and intensity for both circuits at once, and I sent their outputs to separate amps.  While the two LFOs were running at similar speeds they were not synced.  The vibrato effect of the circuit is subtle, but the result of running two unsynced in stereo was lush and immersive.  Can't recommend it highly enough.