Hi Guys

There seems to be some confusion about what's going on with loading, volts, current etc. The good news is that Ohm's Law isn't about to be disproved anytime soon. Volts and current are linked in Ohm's law by resistance, in this case the output resistance of the SH101 - this is about 22k and it connects to +15V in the SH101 gate out circuit.

The MFB EG acts as a load and two in parallel act as a greater load, i.e. more current will flow. If for argument's sake the MFB has an input resistance of 10k then two EGs in parallel would then give a load of 5k. I'll ignore the A140 since that that has a very high input resistance (mine are around 5M to 7M).

The arithmetic for this example is that 15V is loaded by 22k out plus a 5k load = 27k. This acts as a potential divider thus 15/27 x 5 = 2.8V. Not very big! So the more current out the more the voltage drop across the output resistance and hence a smaller gate voltage. So yes it needs a buffer to isolate the SH101 output's high output resistance; I use an A185-1. If you just had A140s then these have such a high resistance that it shouldn't make any difference.

Hope that helps clear up the mystery.
I'd be inteested if anyone can tell me what the MFB EG input resistance actually is.

Cheers
Tony

--- In Doepfer_a100@yahoogroups.com , Monroe Eskew <monroe.eskew@...> wrote:
>
> Pardon if this is a dumb question, but are you sure you're measuring voltage
> and not power Is Ohm's law really that blatantly false I've noticed VCOs
> don't respond to voltage only; they are influenced by the amperage as well.
>
> On Sun, Nov 15, 2009 at 2:43 PM, Computer Controlled <acidted@...>wrote:
>
> >
> >
> > That's why there are Buffered Multiples, passive ones drop the voltage
> > levels. So they need to be buffered to keep them at original levels.
> >
> > I just didn't think that the level would drop by so much!
> >
> >
> > Monroe Eskew wrote:
> > > It's strange because in theory the voltage should not drop since these
> > are
> > > parallel circuits-- only the current should change.
> > >
> > > On Sun, Nov 15, 2009 at 2:16 PM, Computer Controlled <acidted@...<acidted%40gmail.com>
> > >wrote:
> > >
> > >
> > >> I've noticed recently that the A-180 Multiple really cuts the voltage
> > >> signal down quite substantially. I just got an MFB Dual ADSR and noticed
> > >> that when i mult the Gate Output of my SH-101 by 3x, it drops the gate
> > >> voltage down to where the MFB won't trigger anymore. Basically, i had it
> > >> set up where the gate out went into the A-180, then the first 2 outs
> > >> went to the two Gate Ins on the MFB and the 3rd out went to my A-140 EG.
> > >> If i pulled the cable out that went to the A-140, the MFB would fire,
> > >> but not with it inserted. However, it works if i use my 303, which has a
> > >> hotter Gate signal. I checked the gate out voltages coming of the 101
> > >> direct, then at each output of the A-180. I got the following:
> > >>
> > >> Direct Out from 101: 11.56v
> > >> Into the A-180 w/no other cables inserted: same as above
> > >> with 2 cables inserted: 7v
> > >> with 3 cables inserted: 5.5v
> > >>
> > >> This is quite a bit of voltage drop if you ask me. Is there anyway to
> > >> mod the A-180 so it doesn't eat up all my voltages
> > >>
> > >> -Larry
> > >>
> > >>
> > >>
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> >
> >
>
>
> [Non-text portions of this message have been removed]
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