> Hi list !
> I'm working on a robot looking funny cabinet for my A100 stuff and I
> wish to insert lights that would be controlled by CV so that the
> robots glitters as the sound evolves (same CV must be able to control
> lights and modules). I'm not a pro in electronics and need some advices.
> These are the lights I plan to use (at least two of them, with
> different colors):
> http://www.selectronic.fr/article.asp article_ref_entier=80.2400-2
> So arrays of 27 LEDs running on 12VDC average power 3.3W.
> I thought about using directly the splitted CV to feed the LEDs but I
> don't know if this may cause some issues with the A100 power supply
> and with the other part of splitted (passively) CV signal.
> I guess it is more appropriated to use a device that would control
> (with incoming CV) another 12VDC PSU that feeds the lights. I thought
> about a simple op amp follower but I don't know if that's enough.
> So if you got any idea about the electronics I should use and if you
> have already dealt with CV lights please share your experience.
>
> I'll post some photos and videos when the monster's ready !
> Cheers,
> Max.

You need a DC coupled power amplifier to control the LED bar from a control
voltage. Connecting an A-100 control voltage directly to the LED bar will
not work as the output of a module cannot be used to drive loads but the
control voltage input of another module. The best solution would be a power
voltage-to-current converter as the brightness of LEDs is nearly
proportional to the current but not to the voltage. But a voltage amplifier
would work as well. Sorry there is no module that could do this job. The
simplest solution would be an operational amplifier with two power
transistors in the output (a standard circuit for an electronics engineer).
But without DIY experience this will be a problem :-)

I can send you the schematics of such an amplifier as it's exactly the same
function as the power amplifiers we built currently for Kraftwerk to run
their robots on stage via Midi with a Midi2CV interface. The power amplifier
converts the control voltage coming from the interface to a power signal
that can be used to run the motors of the robots. If one connects a LED bar
instead of a motor it's just the same function.

Best wishes
Dieter Doepfer