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funkyfarm
Joined: Jan 21, 2007 Posts: 583 Location: France
Audio files: 3
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Posted: Sat Aug 23, 2008 3:40 pm Post subject:
Bridechamber : CatGirl VCO with VC Waveshapers Subject description: waveshapers ? |
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I wonder which vc-waveshapers are involved here, with CGS VCO.
It could be based on CGS-29 ?
CatGirl Synth VCO with VC Waveshapers
http://www.bridechamber.com/bridechamber.com/C%20VCO.html |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Sat Aug 23, 2008 5:49 pm Post subject:
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no extra boards, that is the VCO with all the options on the PCB.
it is a well thought out panel, so a good guide for people building the VCO for the 1st time |
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funkyfarm
Joined: Jan 21, 2007 Posts: 583 Location: France
Audio files: 3
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Posted: Sat Aug 23, 2008 5:56 pm Post subject:
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Waouh !
thank you, i'll take a look at this beast. |
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Dego
Joined: Apr 22, 2008 Posts: 139 Location: Sweden
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Posted: Tue Aug 26, 2008 8:44 am Post subject:
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andrewF wrote: | no extra boards, that is the VCO with all the options on the PCB.
it is a well thought out panel, so a good guide for people building the VCO for the 1st time |
I can´t see the suboscillator. But I am tired and on my way home from work so perhaps I missed it...
Its a great layout anyway! |
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neandrewthal
Joined: May 11, 2007 Posts: 672 Location: Canada
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Posted: Tue Aug 26, 2008 1:19 pm Post subject:
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Dego wrote: | andrewF wrote: | no extra boards, that is the VCO with all the options on the PCB.
it is a well thought out panel, so a good guide for people building the VCO for the 1st time |
I can´t see the suboscillator. But I am tired and on my way home from work so perhaps I missed it...
Its a great layout anyway! |
It is the block in the bottom right, shown attached to the square output, but it is up to you to connect it. I would highly recommend not doing this, as you will miss out on the independent ramp wave lfo the staircase output can produce on it's own and you can still patch in the square wave (or anything else) when you want to divide. _________________ " I went through quite a few trannies til I found one I liked" - Wild Zebra |
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Dego
Joined: Apr 22, 2008 Posts: 139 Location: Sweden
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Posted: Tue Aug 26, 2008 1:48 pm Post subject:
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I meant I could not see the suboscillator on the bridechamber layout. But your remark is wise. I have just build 2 cgs vcos and are a bit confused about how to design the panel. But Bridechamber version gives good ideas. |
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urbanscallywag
Joined: Nov 30, 2007 Posts: 317 Location: sometimes
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Posted: Fri Aug 29, 2008 12:13 pm Post subject:
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Hopefully my question isn't too off topic for this thread.
Would omitting the input attenuator for the triangle/sine shaper be a mistake? It seems like the input attenuator and shape control might have some overlap. |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Fri Aug 29, 2008 5:51 pm Post subject:
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Do you mean the one labelled 22k Trim?
It is a trimpot on the PCB, doesn't go to the panel. |
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urbanscallywag
Joined: Nov 30, 2007 Posts: 317 Location: sometimes
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Posted: Fri Aug 29, 2008 6:29 pm Post subject:
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No, on the Bridechamber panel for example, tri/sine in. |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Fri Aug 29, 2008 6:39 pm Post subject:
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I see -
On the regular VCO PCB, it is a trimpot, marked WS Trim.
So, you need at least a trimpot, but not necessarily a pot on the panel.
But I imagine a panel-mounted pot would allow you to get some good waveshapes. Bridechamber are very good at getting all the options to the front panel. |
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urbanscallywag
Joined: Nov 30, 2007 Posts: 317 Location: sometimes
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Posted: Fri Aug 29, 2008 6:41 pm Post subject:
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Embarrassing, I should have looked at the schematic. I didn't take the time and since there isn't a front panel-pot wiring guide like some of Ken's other stuff, I just referenced the Bridechamber panel.
Anyhow thank you. |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Fri Aug 29, 2008 7:36 pm Post subject:
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don't be
it is difficult working out a panel for this board.
My 1st CGS VCO has a jack labelled CVSN, which was to connect directly to an opamp input with no resistor in the path - luckily i realised it's purpose whilst wiring up the panel and left it unconnected.
CVSN is for people who want extra 1V/O inputs and can mount the 100k resistors on the panel rather than the PCB - there shouldn't actually be any jacks labelled CVSN |
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camelneck
Joined: Sep 27, 2008 Posts: 68 Location: KY (USA)
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Posted: Sat Nov 01, 2008 7:18 pm Post subject:
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>>CVSN is for people who want extra 1V/O inputs and can mount the 100k resistors on the panel rather than the PCB - there shouldn't actually be any jacks labelled CVSN<<
I guess that is one way to use it. I'm not very familar with the VCO, but I think I remember Ken mentioning in his description that this is the point where you can connect your Fine Tune pot if you so desire one. |
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camelneck
Joined: Sep 27, 2008 Posts: 68 Location: KY (USA)
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Posted: Sat Nov 01, 2008 8:26 pm Post subject:
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I'm planning on buying this VCO and I am also considering buying one of the front panels from bridechamber.
Tonight, I printed out a picture of the bridechamber front panel. This panel has 13 pot holes and I planned to write the value of each of the 13 pots on this front panel printout. I studied the schematic on Ken's CGE website carefully, but was surprised that it only showed the 5 trim pots and 4 other pots. These 4 pots included two 20K processor pots (neither of these appear on the bridechamber panel), the "Shape" pot (which is a 25K Lin pot), and the CVSP (suboscillator) manual adjust pot (which has no recommended value beside it). (Could this CVSP pot be the same as the pot labeled "Stairness" on the bridechamber front panel?)
Looking for more info, I decided to read the entire text for this project including the BOM, but that only provided info on 2 additional pots--the Fine Tune and Coarse Tune pots (which are both 100K linear). I then noticed that Ken made no wiring diagram for the VCO module. Normally, Ken includes a wiring diagram that shows possible panel pots along with their values. (Check out the wiring diagram for the Waveform Multiplier for a good example of this).
Other than the Shape, Fine Tune, and Coarse Tune pots, does anybody know the recommended value for the other 10 pots that appear on the bridechamber front panel?
I have listed the names of all 13 pots below including the recommended values for the first 3 pots. Does anybody have any recommendations for the pots without values? Has bridechamber ever addressed this issue about the 13 pot values?
1) Coarse Tune (100K Lin)
2) Fine Tune (100K Lin)
3) Shape (25K Lin)
4) +/- CV (Could this be 1 of the processor pots?)
5) EXP CV
6) LInear CV
7) PW
PWM
9) Tri/Sine In
10) Shape CV In
11) Staircase In
12) Stairness
13) Stairness CV
Some of these pots, especially all of pots for the CV inputs seem to be overkill, and if I build more than one of the VCO modules, I'm sure I'll eliminate some of these and perhaps add some others such as 1 or 2 of the Processor pots. |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Sat Nov 01, 2008 9:44 pm Post subject:
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There is a single line in Ken's description, right above the red 'REV02' -
"The best value for the pots is 100k lin, though 50k lin would be usable."
Probably the processor pots are the ones you want to be 20k (or 25k should be ok), the rest are flexible. |
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camelneck
Joined: Sep 27, 2008 Posts: 68 Location: KY (USA)
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Posted: Sun Nov 02, 2008 12:43 pm Post subject:
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andrewF wrote in a previous post (Subject: CGE VCO),
>>In fact, 8 of my CGS VCOs only have the CV processor inputs and no 1V/oct at all<<
Certainly you must have several VCO's with 1V/oct inputs. Just how many VCO's (ie CGS VCO's do you have in your modular system, Andrew? It must be capable of kicking some serious ass!
>>There is a single line in Ken's description, right above the red 'REV02' -
"The best value for the pots is 100k lin, though 50k lin would be usable."<<
I read this, but I thought it applied only to the Coarse and Fine Frequency controls that he mentioned in the previous paragraph. I guess you should know since you've built at least 8 of these VCO's.
Thanks for your input! |
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camelneck
Joined: Sep 27, 2008 Posts: 68 Location: KY (USA)
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Posted: Sun Nov 02, 2008 1:22 pm Post subject:
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After reading several other posts, I think the most confusing thing about this VCO is the very unusual Suboscillator/Staircase Generator section. I can certainly understand why. If you just look at the schematic, this section of the VCO appears to be a combination of an LFO and a Staircase Generator driven by the VCO (or an optional input).
I didn't realize that the pulse output is a suboscillator output until after I completely read the description. I was only familiar with suboscillators that used frequency dividers like the 4520 or flip flops like the 4013.
I wish Ken would have written more about how this section works in his description, but I'm sure it will all make sense after I study the circuit in more detail and get a chance to build and play around with the VCO.
I do have a few questions that would help in the meantime if anybody would be so kind to take a stab at them.
About halfway through Ken's description there is a table with an entry for the CVSP node. It says that the CVSP node should be wired to the >>Wiper connection of the manual setting pot for the sub-oscillator<<
1) How does this particular pot affect the suboscillator?
2) What effect does this pot have on the staircase generator?
3) Is this the same pot as the one which is labeled "Stairness" on the bridechamber panel? If not, what does the "Stairness" pot do exactly?
This final question is not related to the suboscillator section.
4) Does anybody know what the pot labeled "+/- CV" on the bridechamber panel suppose to do? Could this pot be equivalent to one of the 20K processor pots that are shown on the CGE schematic?
Thanks. |
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Luka
Joined: Jun 29, 2007 Posts: 1003 Location: Melb.
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neandrewthal
Joined: May 11, 2007 Posts: 672 Location: Canada
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Posted: Sun Nov 02, 2008 6:46 pm Post subject:
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camelneck wrote: | 1) How does this particular pot affect the suboscillator? |
It changes the division ratio.
Quote: | 2) What effect does this pot have on the staircase generator? |
It adjusts the speed of the resulting ramp wave when there is no input.
Quote: | 3) Is this the same pot as the one which is labeled "Stairness" on the bridechamber panel?
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Yes. _________________ " I went through quite a few trannies til I found one I liked" - Wild Zebra |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Sun Nov 02, 2008 10:06 pm Post subject:
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camelneck wrote: |
Certainly you must have several VCO's with 1V/oct inputs. Just how many VCO's (ie CGS VCO's do you have in your modular system, Andrew? It must be capable of kicking some serious ass!
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I have built 13 CGS VCOs, strangely, only 1 with the sub-oscillator. Still have a couple of spare boards so the next ones will get sub-osc'd for sure.
dunno about ass-kicking, maybe, if i spent as much time playing synths as I do building
having too many VCOs running can be the audio equivalent of mixing too many different colours of paint together and you end up with murky poo-brown.
I rarely use more than two VCOs in a patch, though often have 3 or 4 separate patches set up at once. |
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