Voltage Controlled Divider CGS09 -- weird module!

Pulse Emitter · Joined: Apr 11, 2008 Posts: 9 Location: Portland

finally got this working, i think. main hang up was with the switched jack at the CV input. apparently the CVI point needs to be connected directly to CVN while a signal is coming through. the schematic shows CVI and CVN only connected when nothing is plugged in via the switched jack. nothing came through when wired that way. anyone else experience this?

so i think this module works. it doesn't seem to function like other dividers i've used. not sure yet how i'm going to make use of it, but only just got it working today, need to experiment more. i guess it puts out some odd pulse waveforms that could be good as LFOs or as a signal processor for VCOs. really don't know what i'll do with the staircase outs. also can't seem to figure out what the trim pots do.

any tips?

thanks,
Daryl

Pulse Emitter · Joined: Apr 11, 2008 Posts: 9 Location: Portland

oh yeah, here's a link to the schematic for reference:
Posted Image, might have been reduced in size. Click Image to view fullscreen.

andrewF

Pulse Emitter · Joined: Apr 11, 2008 Posts: 9 Location: Portland

didn't think about it hurting the module connected but you're right! wired it back per schematic immediately.

tested the switched jack, it's good.

sorry, should have read the trim pot setup in the notes, forget that was there.

but man, now i'm still having the same problem. when a signal is plugged into the CV jack, no action, LED stays on solid--unless it's just barely resting in there making contact with with both points of the switched jack (the lug of the pot opposite ground, and CVN). unplugged nothing comes through either. the Division pot doesn't help, neither do the trims.

i'll have a look at the board and schematic and scratch my head a little bit... thanks for the help, look forward to experimenting with it once it's up and running!

more later,
D

Pulse Emitter · Joined: Apr 11, 2008 Posts: 9 Location: Portland

yippee!! that was quick, i traced the CVN point on the board through the 1k to +15V, only to find a missing jumper! was not connecting to +15V. there are a lot of jumper wires to be soldered onto this board, and while i scanned it multiple times, just didn't catch that one.

just set up the trims per the notes. seems to be working, the staircase out looks much better on the O-scope. only now my LED isn't flashing Rolling Eyes

anyway, making progress, thanks again... much experimenting ahead with this most interesting module.

cheers,
Daryl

whomper · Posted: Mon Feb 09, 2009 3:21 pm Post subject:

Just got back to my module and found out that my module is too acting weird.... Sad

I get no audio on the "MO" output so could not follow Ken's settings suggestion. I get no output out of the 4024. The led changes flashing speed as I turn the division pot and I get proper division at the LO out, but the 4024 does nothing.

zthee · Joined: Feb 20, 2008 Posts: 414 Location: Stockholm

But the MO output is just the mixer output of the incomming clock signal?

The comp sense pot sets how sensitivite the pre-comparator will be? Which means that if you've set it to high it will not send a clock pulse to the comparator, and that in turn will not drive the 4024?

So either IC3 isn't working, or IC1 is faulty?

Trace the incomming clock pulse? Does it pass the pre-comparator? If so, does it pass the comparator? If so, change the 4024? Smile

I've got a CGS09 in my backlog. Hope to get alu for my panel soon, so I can get it all together!

otherunicorn · Joined: May 11, 2008 Posts: 136 Location: Australia

MO is just a mix of the Clock and other related voltages. It is there so you can use the input stage as an ordinary CV mixer if you are not using the module for dividing.

Funky40 · Posted: Thu Feb 26, 2009 4:04 am Post subject:

I need something like the VC-clock part from the new Motm 730
click on top left corner: http://www.synthtech.com/new_stuff.html (btw. it has very nice Demos on the Motm730 page )
Would the CGS09 do ?

andrewF · Posted: Thu Feb 26, 2009 3:44 pm Post subject:

maybe the VC Divider combined with a CGS36 Pulse Divider would do the job. Not exactly the same as the MOTM but getting close and about $350 cheaper if you DIY.

Funky40 · Posted: Fri Feb 27, 2009 5:04 pm Post subject:

thanks Andrew !
I will try, the 350$ are an argument Wink

and shipping from Ken is so cheap, so no brakes there.
only drawback is the big backlog. Must go thru the haible stuff........

i see REALLY lots of potential to get nice grooves with some CV clockdivison lines.
the full random thing is not really my world as it seems

Funky40 · Posted: Sun Mar 15, 2009 11:21 am Post subject:

I found a CGS09 board while cleaning.
It's popultaed and the module ready for wiring.

something is not clear concerning CVN and CV In.
On the schematic is a 1K resistor on the CVN connectioon which is an output ( to be normalised to the CV in jack as i understand )
On the Board i have 10K. seems that it was also as 10K labeled.

I assume here's an error or am i wrong Question

.............................................................

finally i will wire the CV Manual control separatly and making two CV inputs, each with attenuation.
seemed worth to layout the module this way.
so when wiring directly to a pot i even could omit the Resistor if it's really a 1K, not Question

zthee · Joined: Feb 20, 2008 Posts: 414 Location: Stockholm

I just got mine working. Haven't listened to it. But it seems to function OK.

The staircase down seems to have a bit of offset - it starts like -2V or -3V and then goes downwards. I'll check it tomorrow. Maybe need to change the 100K around IC4b to something different...

andrewF · Posted: Sun Mar 15, 2009 4:52 pm Post subject:

Funky40 · Posted: Mon Mar 16, 2009 4:09 am Post subject:

ok, its clear then,
thanks Andrew !

Funky40 · Posted: Tue Mar 17, 2009 10:52 am Post subject:

I have my module wired up, but have a little issue with trimming:
I cannot get the outputfrequecy following the inputfrequency. ( HO out )
I have a divison by 1:7 as the smallest i can get.
Any tips from down under ?

Funky40 · Posted: Tue Mar 24, 2009 2:08 pm Post subject:

andrewF · Posted: Tue Mar 24, 2009 3:18 pm Post subject:

First thing, check you have 0V at CV IN. If you don't, this probably explains why it won't match frequencies.

If you do:

The 10k resistor and 2k offset trimmer combine to give an offset voltage ranging from 0 to -2.5V.
Try increasing this range, for now just spot-solder a 4k7 resistor over the 10k, so they are in parallel. this will give a range of 0 to -4.5V.

Now try and do the setup routine again.

if it works, measure the offset voltage and replace the 10k with something that will give the appropriate voltage (most likely the 4k7 will do)
Hopefully this will allow you to match the input and output freqs.
It is a bodge tho, doesn't really answer the question of why you cannot set it up with the specified components.

have fun Smile

Funky40 · Posted: Wed Mar 25, 2009 11:31 am Post subject:

Andrew, i've putted the 4K7 in paralell, and turned the trimmer somewhat back,
but i had to turn it again back. when it reached the end i got 1:1 clock.
So 4K7 is very much on the edge.
I don't understand the maths ( serenadi tryed explaine me allready ), so giving it a little more "headroom" then with the 4K7 waht would be right to replace the 10K or maybe just the 4K7 ( don't like to desolder on the borrds )

Thanks Andrew !

Funky40 · Posted: Wed Mar 25, 2009 12:54 pm Post subject:

WOW, the module is fun !
i can make 2voices with one VCO, patched over two LPGs it's allready really cool.
Can't record anymore in the net-PC ( EMU soundcard, good audioquality but driver sucks )

hehe, need two more VC Dividers Laughing

andrewF · Posted: Wed Mar 25, 2009 11:16 pm Post subject:

Have a check the diodes around IC2B are installed corrctly.
If all okay...well
just replace the 10k/4k7 combination with a 2k (or 2k2). This will give you a range of 0 to -7V or so, which will be plenty.
Then do the setup procedure again to get 1:1 input/output ratio.

Keep in mind, this is a bodge, that is effectively masking a problem elsewhere but not solving it. Hopefully it will all work as normal and you never have to think about it again or at least until you build another.
but be aware it may eventually cause other problems.
good thing we are not building medical equipment or passenger jets Razz

oh - a google for 'voltage divider' will turn heaps of introductory articles on calculating this.

Funky40 · Posted: Thu Mar 26, 2009 6:11 am Post subject:

Luka · Joined: Jun 29, 2007 Posts: 1003 Location: Melb.

hey does anyone have any panel designs for this
i need a reference to work from

zthee · Joined: Feb 20, 2008 Posts: 414 Location: Stockholm

It's missing the stair down output though. And the CV in could probably use an attenuation pot.

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Luka · Joined: Jun 29, 2007 Posts: 1003 Location: Melb.

what uses come from the stair ouputs?
i just thought this was a divider

btw is it hard to set accurate divisions?
is it 1v/div or something?