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CV signal Splitter/Buffer

CV signal Splitter/Buffer

2012-01-25 by grayz4sure

I am looking for a CV signal splitter/buffer.

Something I could make on a board or already made board that can take a
single 10k pot or EXP pedal (eg.Roland EV-7) and split that signal out
to several other devices without loosing signal, as well as take tap
tempo out signals on another channel and split them.

I have made a diagram of my project if that helps.

http://img.photobucket.com/albums/v253/jeremysdemo/ExpRouting2.jpg

As you can see in the diagram I also need some sort of polarity switch
as well (which I was hoping I could trigger via a three way toggle, A, B
A+B).

I will be bookmarking this page and checking back periodically.

Any and all help, either with the science behind the DC signals or the
acquisition of parts will be appreciated.

keep shinin

jerm [B-)]



[Non-text portions of this message have been removed]

Re: CV signal Splitter/Buffer

2012-01-25 by Dave Kendall

Hi there.

OK - I'm sure someone smarter will chip in soon, but here goes..

The CGS 37 has 8 voltage followers in the diagram on the right hand
side. If the 10K resistors were omitted, they will act as active
(non-inverting) buffers.
Wire a pair of them with the same input, and you will have two buffered
outputs from a single source - a splitter. The 47pF cap in each may not
be needed - if omitting it, then use a wire link in its place,
effectively joining the output to the inverting input.

As far as the INPUT and switch to EXP 2 (which I guess means expression
pedal) this can be done with a DPDT changeover switch easily.

For the tap tempo side of your diagram, you could try using the
dual-inverting opamps that make up the BASE CV input.
OMIT the 100k resistor joining IC1C pin 9 to IC1D pin 14.
OMIT the 100K resistor joining IC1B pin 6 to IC1A pin 1

The BASE CV circuit now replaces the SPLITTER and POLARITY chip for Tap
tempo and the TOGGLE.

The hole nearest IC1A pin 1 that used to have one end of a 100K
resistor joining it to IC1B pin 6 is now an INVERTING (reverse
POLARITY) output from the BASE CV input.
Point "A" is now a buffered non-inverting output.

To get the toggle and tap tempo inputs connected via a switch, remember
that IC1A and IC1C are connected in a dual inverting configuration,
which means that any input to the circuit must have a 100K resistor
between the jack input and the inverting input of the opamp ... sooo...

To get more than one input to the INVERTING output, use BASE CV in as
one input, and add a second input to IC1A pin 2 via a series 100K
resistor. This will then provide a mix of both sources, with a regular
non inverting output at point "A" and an inverted output from the empty
resistor hole nearest ICIA pin 1.

Use switches to disable one or both inputs (you'll have to work that
bit out yourself....)

You get a bonus mixer too for SPLITTER D1 and D2. The main input to it
is now the SPREAD CV input. Add extra inputs via series 100K resistors
to IC1D pin 13. The output of this mixer will now be where the 330R and
100K resistors meet, which is also point K. This joins neatly to the
input of The Splitter D1 and D2

If this is not needed, simply cut the trace between the join of the
330R and 100K resistors and the input to IC2A pin 3.

I hope that's clear enough! Bottom line, with a bit of experimenting,
you should be able to do it all with a CGS37 - good luck!

cheers,
Dave
Show quoted textHide quoted text
On Jan 25, 2012, at 19:50, grayz4sure wrote:

>
>
> --- In cgs_synth@yahoogroups.com, "grayz4sure" <grayz4sure@...> wrote:
> >
> > CV Mega Mixer?
> >
> > I notice it is out of stock, but would it work?
> >
> or CV Cluster?
>
>
>

Re: CV signal Splitter/Buffer EDIT

2012-01-25 by Dave Kendall

> You get a bonus mixer too for SPLITTER D1 and D2. The main input to it
> is now the SPREAD CV input. Add extra inputs via series 100K resistors
> to IC1D pin 13. The output of this mixer will now be where the 330R and
> 100K resistors meet, which is also point K. This joins neatly to the
> input of The Splitter D1 and D2


Thinking again, this last bit won't work.

Just omit the mixer bit, and cut the trace between the join of the 330R
and 100K resistors, and pin 3 of IC2A

cheers,
Dave

Re: CV signal Splitter/Buffer EDIT no 2

2012-01-25 by Dave Kendall

OK another thing - you'll need to find out what voltages the devices
driven from the expression pedal uses, and what the pinouts are.

Also some info on what the tap tempo and toggle actually are - shorts
to GND, or voltages.

If they are voltages, the CGS 37 should work fine as a CV distributor
with an inverting stage (for B1 and B2)

OK - have to go now, hope someone else can help a bit more......

cheers,
Dave

Re: CV signal Splitter/Buffer

2012-01-25 by sasami@hotkey.net.au

Regular DC Mixer would work just fine as a buffer.
Show quoted textHide quoted text
>
>
>--- In cgs_synth@yahoogroups.com, "grayz4sure" <grayz4sure@...> wrote:
>>
>> CV Mega Mixer?
>>
>> I notice it is out of stock, but would it work?
>>
>or CV Cluster?
>
>
>
>------------------------------------
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>Yahoo! Groups Links
>
>
>
>
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: CV signal Splitter/Buffer EDIT no 2

2012-01-26 by grayz4sure

--- In cgs_synth@yahoogroups.com, Dave Kendall <davekendall@...> wrote:
Show quoted textHide quoted text
>
> OK another thing - you'll need to find out what voltages the devices
> driven from the expression pedal uses, and what the pinouts are.
>
> Also some info on what the tap tempo and toggle actually are - shorts
> to GND, or voltages.
>
> If they are voltages, the CGS 37 should work fine as a CV distributor
> with an inverting stage (for B1 and B2)
>
> OK - have to go now, hope someone else can help a bit more......
>
> cheers,
> Dave
>
thank you I have read all your detailed replies and will be referring to them as the project moves forward.
To answer your question I am not sure what the polarity of the Tap Tempo is (open latching or closed) they are standard tap tempo's used for basically every Boss Effect pedal and Helicon Reverb unit since the 80's, I'd have to look up their manuals and specs to know for sure, but that is why I put a polarity switch on two of the outputs to accommodate those rare devices that work in reverse, I'd like to have a bypass on the polarity switch as well giving me an opportunity to have 4 outs from one Toggle.

thanx again I am going to look up that part...at least I have a direction to go in now with this and what the other patron suggested.

jeremy

Re: CV signal Splitter/Buffer

2012-01-26 by grayz4sure

Ok I did see that on the site,

will it be able to handle all the needs in the diagram? (8 total outputs from two inputs) ? and 1 AUX input to alternate on the second?



jeremy
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, sasami@... wrote:
>
> Regular DC Mixer would work just fine as a buffer.
>
>
> >
> >
> >--- In cgs_synth@yahoogroups.com, "grayz4sure" <grayz4sure@> wrote:
> >>
> >> CV Mega Mixer?
> >>
> >> I notice it is out of stock, but would it work?
> >>
> >or CV Cluster?
> >
> >
> >
> >------------------------------------
> >
> >The CGS Modular Synth home page: http://www.cgs.synth.net/
> >Yahoo! Groups Links
> >
> >
> >
> >
> _______________________________________________________________________
> Ken Stone sasami@... otherunicorn@...
> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>

Re: CV signal Splitter/Buffer

2012-01-27 by sasami@hotkey.net.au

>Ok I did see that on the site,
>
>will it be able to handle all the needs in the diagram? (8 total outputs
from two inputs) ? and 1 AUX input to alternate on the second?

This will only work if your pedal is being used to generate a control
voltage to drive other things. If the other things actually want a varying
resistance, the whole problem gets way too complex.

The pedal would need to be wired as part of a voltage divider. A pull up or
pull down resistor would need to be added, depending on how the pedal works.

Decrease the output resistor from 1k to 330 ohms. It is a self correcting
circuit, so the greater the load, the harder it drives. If one of them isn't
enough, you could have two, each driving four loads.

Beyond that, I can't help you.

Ken
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: CV signal Splitter/Buffer

2012-01-27 by grayz4sure

That makes sense, two of them,
All the devices would normally work off of the same pedal, only I do not want to have 4 identical Expression pedals (Roland ev-7), but one 10k Pot.

I am forwarding all of the suggestions to the engineer of the project, I am just a concept guy who knows what I need as an end result but not how to get there.


thanx again!
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, sasami@... wrote:
>
> >Ok I did see that on the site,
> >
> >will it be able to handle all the needs in the diagram? (8 total outputs
> from two inputs) ? and 1 AUX input to alternate on the second?
>
> This will only work if your pedal is being used to generate a control
> voltage to drive other things. If the other things actually want a varying
> resistance, the whole problem gets way too complex.
>
> The pedal would need to be wired as part of a voltage divider. A pull up or
> pull down resistor would need to be added, depending on how the pedal works.
>
> Decrease the output resistor from 1k to 330 ohms. It is a self correcting
> circuit, so the greater the load, the harder it drives. If one of them isn't
> enough, you could have two, each driving four loads.
>
> Beyond that, I can't help you.
>
> Ken
> _______________________________________________________________________
> Ken Stone sasami@... otherunicorn@...
> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>

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