[sdiy] Juno 106 bonus questions

[Jim Coursey]

Hi, so while I have your attention, a couple bonus / "mod" questions.  At a time when I thought I'd irreparably damaged my module board I started somewhat foolishly messing around with simple mods to the Juno and came up with some ideas that are pretty cool but want to know how bad they are (electronically).  (P.S.  I don't think I tried any of these prior to my previously mentioned PWM problem, so I don't think there's a relationship there.)

1) On the Jack Board, I find that by replacing R8 (2.2M) with a 2M pot, and maybe adding a 10k resistor in series, I get a chorus sound which goes from standard grade Juno 106 chorus on one end of the pot, to very lush and over-excited on the other end.  (Essentially this seems to increase both the depth and rate of the LFO that feeds the BBD chorus.)  As nice as the standard Juno chorus is, it's nice having even more range to choose from.

2) On the Bender Board, you can disconnect the wire from the wiper of the pitch bender, and instead wire the wiper to the switch on a switching jack, and use the jack for CV input, routing the CV jack's tip to R12.  When CV is plugged in, the Bender doesn't do anything but the Pitch and VCF sliders on the Bender Board conveniently become CV mod level settings.  Seeing as the Bender is a voltage divider mixing +/-15v from the rails, it doesn't seem like this one is very controversial.

3) Most dubious:  On the Panel Board, if you wire a CV input via 4.7k resistor and 100k pot to the 4052 end of any of R1-16 (4.7k), you can add CV to whichever slider you choose (say, LFO rate, or Sub Level, Resonance, etc). This is pretty simple to do, but I worry about doing any damage to the 4052s or subsequent chips.  And I suppose this is unideal as it's a passive averager not a summer, but I'm just thinking of easy little ways to interface my Juno to my modular gear.  So how reckless is this idea?  Should I buffer the CV input at least?  (Again I don't really want to change the existing slider circuitry, just add inputs)

Service manual with relevant schematics here:

http://www.hinzen.de/midi/juno-106/manual/juno-serv.pdf

-Jim