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cleaninglady
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Post by cleaninglady » Tue Mar 26, 2013 6:19 pm

I just looked at the build docs for all four boards in the SWAMP , just a 10K for SENS. The rest 100K.

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Post by jamb » Wed Mar 27, 2013 9:19 am

couple questions about these:

has anyone use the BUD enclosure that is only 2 inches deep as opposed to the 3 inch one?

also, who is the best source for the original davies 1900H knobs?

thanks :tu:

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neilbaldwin
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Post by neilbaldwin » Thu Mar 28, 2013 3:24 am

I got my Davies clones from Doctor Tweek here in the UK

http://www.doctortweek.co.uk

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neilbaldwin
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Post by neilbaldwin » Fri Mar 29, 2013 12:44 pm

The inevitable, my SWAMP isn't working properly post!

Finished wiring up the sequencer side today so I thought I'd test it before going any further.

Sending a regular gate (or trigger) into the UP input steps through the stages OK but sometimes it holds on a step or sometimes it will pass to the next step quicker than the pulse input.

The DOWN input doesn't work at all.

Any pointers?

Edit: as a quick test I replaced the LM393 in case it was dodgy but no change.
Last edited by neilbaldwin on Fri Mar 29, 2013 1:10 pm, edited 1 time in total.

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Post by astroschnautzer » Fri Mar 29, 2013 1:10 pm

jamb wrote:couple questions about these:

has anyone use the BUD enclosure that is only 2 inches deep as opposed to the 3 inch one?

also, who is the best source for the original davies 1900H knobs?

thanks :tu:
its too shallow for all exept swamp, the rest of the panels need to have a few stacked pcb's so it gets too deep...

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Post by jamb » Fri Mar 29, 2013 4:11 pm

aha, thanks astroschnautzer.

i might try to get my BOG into a 2.5" STS low-profile chassis.. i measure and it should be fine. anyone else have any luck with that?

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Post by cleaninglady » Fri Mar 29, 2013 5:04 pm

neilbaldwin wrote:The inevitable, my SWAMP isn't working properly post!

Finished wiring up the sequencer side today so I thought I'd test it before going any further.

Sending a regular gate (or trigger) into the UP input steps through the stages OK but sometimes it holds on a step or sometimes it will pass to the next step quicker than the pulse input.

The DOWN input doesn't work at all.

Any pointers?

Edit: as a quick test I replaced the LM393 in case it was dodgy but no change.
The behaviour sounds a little like the effect i get when i feed signals into up and down at the same time.

Are the two BC557's near the 47K's alright ? That seems to be the spot on the schematic where both of those jacks join and go off to other areas. :hmm:

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Post by neilbaldwin » Fri Mar 29, 2013 5:13 pm

cleaninglady wrote:
neilbaldwin wrote:The inevitable, my SWAMP isn't working properly post!

Finished wiring up the sequencer side today so I thought I'd test it before going any further.

Sending a regular gate (or trigger) into the UP input steps through the stages OK but sometimes it holds on a step or sometimes it will pass to the next step quicker than the pulse input.

The DOWN input doesn't work at all.

Any pointers?

Edit: as a quick test I replaced the LM393 in case it was dodgy but no change.
The behaviour sounds a little like the effect i get when i feed signals into up and down at the same time.

Are the two BC557's near the 47K's alright ? That seems to be the spot on the schematic where both of those jacks join and go off to other areas. :hmm:
Sorted half of the problem. Seems that it doesn't like being ungrounded so I ran a ground from the power supply and the forward (UP) behaviour is now working spot on.

However, still can't make the reverse (DOWN) happen.

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Post by neilbaldwin » Sat Mar 30, 2013 6:14 am

Sorted it - dodgy 10n cap before the DOWN input hits the LM393. Then I managed to lift a pad when removing it (so tricky to work on once its all assembled!) but a quick back-of-the-board splice job and its good to go :)

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Post by Setherian » Wed Apr 03, 2013 7:52 pm

Hi guys, Im building a Marsh panel and I have just the ADSRs ready for testing, for weeks actually, because Im still waiting for a new components package to arrive so I can finish the other modules, and Im very disturbed and sad and weak and everything bad possible with the current status of my build.

Because none of the ADSRS work and to make things worse, I even got a third one from a friend who had 2 populated for a future project and it also does not work.

The problem is almost the same, I didnt manage to make any of them have a gate in gate out according to the pulse in, the gate is always on hi, no matter what pulse source I send to them, the gate will not switch status in any of the three pcbs or it goes down and stay down forever. Knobs dont affect anything that I can grasp in any of them either besides some sort of abstract reaction that will make one of them go lo and stick like that until I turn the panel on again..

I swear they are all properly populated, there is no short circuits and the wiring is perfect also, could it be a "cold soldering"? Or the BC547/557?
I "kinda" checked all pads, I cant find anything wrong..

I know troubleshooting like this will almost certainly not lead to much but I have tro try right?

So perhaps we can go step by step? OR just one step??What could cause the gate in not reacting? Where to look?

:deadbanana:

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Post by Cheradenine » Tue Apr 09, 2013 5:59 pm

Another BOG out in the wild...commissioned by a fellow wiggler :nana:

There's some modifications added :
-Push/pull knobs for selecting slow/fast rate for the LFOs (fast : from 3Hz to 137Hz - 10nF, slow from 0.055Hz to 3Hz - 470nF)
-Push/pull knob for choosing stair up/down on the VC divider
-Amplifying buffers for the variable tri/sine VCOs outputs
-Amplifying buffers on the outputs of the VCAs for adding some gain - these are too quiet otherwise.
This time I haven't used the buffers on the filter PCB...using them lead to audio bleed in the filter output, so I added an additional stripboard with all the buffers, and each buffer take his power supply from the PCB it completes.

Image
Image
Image

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Post by GrantB » Tue Apr 09, 2013 9:29 pm

:yay: bravo Cheradenine!

I like your method of holding the panel off the desk.

How deep of a boat do you need to fit that panel with the push-pulls?

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Post by Cheradenine » Wed Apr 10, 2013 4:56 am

Thanks !

The panel fit with no problem in the usual 3" deep BUD box. I just have lifted a bit the PCBs sitting on top of the p/p knobs :
Image

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Post by iopop » Tue Apr 16, 2013 6:24 am

Not sure if this have been asked before, but can CGS91 be used with these panels.

ie will the panel mount holes line up correctly ? I'm at work so no access to a ruler and/or panels.

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Post by widdly » Tue Apr 16, 2013 8:35 pm

The CGS91 would be great with these panels. It would save a lot of measuring and drilling ( and swearing ).

I didn't use the CGS91, but I used the dimensions from the diagram on the CGS91 page to make a drilling guide for a MARSH and a SWAMP panel. Worked nicely.

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Post by Setherian » Wed Apr 17, 2013 2:09 pm

Guys , check this out, I'm slowly building a Marsh panel and I'm stuck with 4 ADSRs that doesnt work, yes freaking 4 PCBs that will not work in conjunction with my Serge. The problem is the same, the Gate will not go HI (LED down).

The thing is, after I didnt manage to get my 2 PCBs from the MArsh kit to work I asked for a professional builder friend of mine who happened to have the same kit and all pcbs already populated to land me his pcbs to test, I wired the first one, didnt work, no Gate/trigger change, then I thought 'damn, i must be the worst builder in the world, I will take the last PCB and ask my friend to wire and test, went to his place we wired together the 4th one , but I didnt bring my Serge with me, so we tested with a sequencer and synth of his which I think works on 15 volts , guess what, the 4th PCB worked like a charm, beautiful , I was so excited, brought my Marsh home, turned it on , took a gate out from my Serge Animoo and what happens? Nothing. Gate wont go HI no matter what config I do with the knobs or if I take a gate out from the SSG Comparator even (its higher then the rest).

So now I will have to go back and test again with his sequencer , but it seems to me like its a problem here, could it be that the Serge gates are not hi enough to gate in the CGS ADSR with a regular build?
Last edited by Setherian on Wed Apr 17, 2013 10:20 pm, edited 1 time in total.

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the bad producer
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Post by the bad producer » Wed Apr 17, 2013 6:05 pm

Cheradenine wrote: ...-Amplifying buffers on the outputs of the VCAs for adding some gain - these are too quiet otherwise....
Hey Cheradenine, never got round to modding mine, how did you go about doing yours?

cheers

charlie

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Post by widdly » Wed Apr 17, 2013 8:34 pm

Setherian wrote: So now I will have to go back and test again with his sequencer , but it seems to me like its a problem here, could it be that the Serge gates are not hi enough to gate in the CGS ADSR with a regular build?
I built two of these on the weekend and the gate input needs about 6v.

If you look at the schematic you can see there is an onboard 5v supply connected to the gate in via a 470k resistor. This 5v is made by the R20/R21 voltage divider which would give 5v if the supply was +12v. On a 15v supply it gives 6.25v. I think maybe changing R20 to 68k would fix it. I will try it tonight.

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Post by Setherian » Wed Apr 17, 2013 10:24 pm

Well, I spent the whole day on this and I managed to make the 4th one work again, also with Serge, so I can guarantee now that the conventional build does work with Serge flawlessly!

Tomorrow I will go into the second one comparing every freaking atom of it!

I kinda needed this kick, was starting to feel miserable...

:yay:

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Post by Setherian » Wed Apr 17, 2013 10:29 pm

About the Dual VCA, I will wait for more info on the "mod" , now I wonder, does that quietness also a bad thing when using it only for CV or the mod will benefit both options?

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Post by Cheradenine » Thu Apr 18, 2013 3:36 pm

For the Dual VCA I just added a non inverting amplifying buffer after the output of each VCA, with a gain of 3 (!)
I used the same schematic than the buffers found on the CGS77 board (at the bottom here), with RG=51k, and with TL072 (I didn't have TL071 on hand) instead for making individual buffer for avoiding audio bleed, and built it on stripboard.

Each buffer takes its power supply from the board it helps, for avoiding any interference between buffers.
On the VCA board I used the pad provided to cut the PCB in half for taking the +12/-12/GND

With this buffer the VCA is close to unity gain (something like 0,8) with a 5V CV.
Unity is reached with a CV of 7,5V.
For this panel the pot act as an offset, by sending attenuated 12V to the CV input. When fully CW, there's more gain than unity (something like 1,2).

An easy way to try that on the BOG is to use the buffers on the CGS77 PCB, but you will get audio bleed in the out of the filter.
Setherian wrote:...does that quietness also a bad thing when using it only for CV or the mod will benefit both options?
Yes that's a bad things for CV, even worst than for audio since you can't adjust level for matching the audio quietness.
The mod will boost the output of the VCA, regardless if it's audio or CV.

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Post by widdly » Fri Apr 19, 2013 6:58 am

Marsh is finished! Now I've got a complete set :nana:

[video][/video]

Loving the infinite melody and the eADSR's. :sb:

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Post by themanthatwasused » Fri Apr 19, 2013 6:52 pm

widdly
:banana: :nana:

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Post by widdly » Mon Apr 22, 2013 12:08 am

Cheradenine wrote:For the Dual VCA I just added a non inverting amplifying buffer after the output of each VCA, with a gain of 3 (!)
I used the same schematic than the buffers found on the CGS77 board (at the bottom here), with RG=51k, and with TL072 (I didn't have TL071 on hand) instead for making individual buffer for avoiding audio bleed, and built it on stripboard.
I have the same problem with the VCA's. I get 1.7v OUT with 5v IN and 5v CV. I think an easier way to solve the problem would be to increase the 100k in the feedback path of the input summer to about 300k.
Last edited by widdly on Mon Apr 22, 2013 12:14 am, edited 1 time in total.

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Post by widdly » Mon Apr 22, 2013 12:11 am

Setherian wrote:Well, I spent the whole day on this and I managed to make the 4th one work again, also with Serge, so I can guarantee now that the conventional build does work with Serge flawlessly!
Yeah I ended up with the same conclusion...mine are working fine as is. I was getting confused because the trigger inputs on these work differently to other ADSR's.

I did try changing the 47.5k in voltage divider and it didn't have any noticeable effect.

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