Discussion about the Korg PolySix synthesizer

and additionally from the same page:

_"Important note (especially for A-188-1 users)_: /The A-188-1 uses 
single BBD circuits, which can be adjusted to minimize the clock noise 
as the outputs of the used BBD circuits are symmetrical (for details 
please refer to //A1881_adjustment.pdf 
<http://www.doepfer.de/service/A1881_adjustment.pdf>, trimming 
potentiometer P10). By way of contrast the BBD circuit used in the 
A-188-2 (MN3011) has six asymmetrical outputs that cannot be adjusted to 
minimize the clock noise. In addition the clock noise of the six outputs 
adds up. From there the clock noise of the A-188-2 is more intense than 
of the A-188-1. This is caused by the properties of the MN3011 but not a 
mistake of the module ! If you feel that the clock noise is too much you 
have the right to return the _unused_ module within 14 days (i.e. the 
module has no scratches or prints, e.g. from srewing into the frame)."/