Info from online:

The BOSS VB-2 is the king of all vibratos.  With its perfect sine wave LFO (low frequency oscillator), warm MN3207 bucket brigade delay analog vibrato, and depth ramp feature, nothing else sounds like it.  The BYOC Analog Vibrato flawlessly recreates the original circuit.  But we've made a huge improvement by adding a designated bypass switch and ramp switch.  The original VB-2 and the new VB-2w are not true bypass.  Not even when you have it in "bypass" mode.  The BYOC Analog Vibrato is true bypass.  And it's a lot less confusing than the original bypass/ramp system.  It's either on or off, and it's either in ramp mode or not in ramp mode.