OBI expander

[Paul Perry]

At 01:29 AM 27/07/97 -0700, BJ from the land of home distilling wrote:
......some very relevant comments on PS's fantasies re Xpander cloning......

the unique power of the xpander comes from the extensive routing
possibilities, like the K2000. And the flexibility of the filters.
the downside in my experience is the lumpiness of the control over the LFO -
the d to a convertor has not enough resolution at one end of the range - and
the unreliability of the whole thing (well, I have 2 of them and they are
both intermittent.....reseating the chips helps for a day or so ...... but i
don't fancy unsoldering the sockets then soldering the chips straight back in)

If somebody wanted to make an xpander replacement today then i am thinking a
single board per voice with a serial digital control line. 
and a single control surface that has pots corresponding to various parts of
the voice board, the idea being wiggle the pots on the control board and
have them generate digital control signals to go the chosen voice
board......and when you are happy with what the voice board is set like then
store the settings and move on to the next board.....and similarly for the
analog inputs and outputs to the boards.....and some reconfiguration of
signal path on the voice board.....

a major undertaking, yes.......but the art of design is knowing what to
leave out, and the realisation that flexibility is of no use if it is so
difficult to control the unit that one can't use it. the power of the
xpander is that it is almost as flexible as a true modular yet has no patch
cables.

wel i guess this proves i have as hyperactive an imagination as
anyone....but I know I couldn't build one of these, and if i did I couldn't
sell it for less than a secondhand xpander. 

paul perry melbourne australia

"and then your hand fell in the potty and you woke up"....Hungarian folk saying