DS 7 clone

umschmitt · Posted: Fri Sep 09, 2011 8:20 am Post subject:

Miracle ! I can see !
Now I'd like to hear how it sounds.

jumunius · Posted: Fri Sep 09, 2011 10:12 am Post subject:

umschmitt · Posted: Fri Sep 09, 2011 2:00 pm Post subject:

Thank you very much for these samples. But hey ! you changed voice since your instant hit "No Bump / Bump / Big Bump"* !
Some settings sound quite interesting (specially the one with the jumper), though others sound to me simply more like an LFO on a VCO. I guess it turns into chaos and weird things as soon as you move the knobs, since you feed LFO and VCO into another… Or am I wrong ? Anyway, I may consider adding an "UFO switch" on my ever growing mutant DS-7, if you don't mind. Thanks for that too !

* Actually it could be fun to use this NB/B/BB track as the base of a song, vocals and bass drum are already there !

jumunius · Posted: Fri Sep 09, 2011 2:45 pm Post subject:

umschmitt · Posted: Mon Sep 12, 2011 3:23 pm Post subject:

umschmitt · Posted: Tue Sep 20, 2011 5:15 pm Post subject:

Hey jumunius. Funnily, I don't seem to be able to reproduce your UFO sounds (option plain wire connection)… Weird weird weird.

jumunius · Posted: Wed Sep 21, 2011 11:28 am Post subject:

It's weird that the simplest part of this mod (jumper) doesn't work for you. Are the DS7 and DS8 are more different than I think? Or have we modded (or misbuilt) one of our units so this either works or doesn't?

Thankfully I have a DS7 that is in disuse (no room in my rack right now). I'll plug it in tonight and see what happens when I connect those wires.

I meant to say, regarding your earlier email, that I thought you were still modding and going to release more mods. So that's why I was curious what other details you might release in the future. But if not, no worries, I'm trying to resist the temptation to mod further.

umschmitt · Posted: Wed Sep 21, 2011 12:46 pm Post subject:

umschmitt · Posted: Thu Sep 22, 2011 5:24 am Post subject:

An image might be clearer than my confuse explanations.
(and I need to exercise with that *#&ø Gimp !)

switchable LFO shape for DS-7&8.jpg

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an overeasy mod!

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jumunius · Posted: Thu Sep 22, 2011 10:03 am Post subject:

umschmitt · Posted: Fri Sep 23, 2011 7:02 am Post subject:

feggster · Joined: Sep 12, 2011 Posts: 52 Location: uk

hi all, great thread here .. lots of info. I have just came into possession of an original ds-7 (actually a JHS D-2!) I had to replace pots and rewire to get it to work, it now sounds great! looking at the pcbs inside i noticed an empty area of the circuit, I imagine they used the same pcbs for both ds7 and ds8... so my question is: can anyone help with a conversion? Laughing

I have added a jpg that shows what I'm talking about.
p.s. could not find a image of the ds8 board using Google....

cheers.
Geoff.

Coron_DS-7_both.jpg

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umschmitt · Posted: Mon Sep 26, 2011 3:19 pm Post subject:

Hey. No happy DS-8 owners passing by… Ready for some reverse engineering ? The 741 is obviously in the middle, and I guess the transistors are top left (solder side). Good luck !

feggster · Joined: Sep 12, 2011 Posts: 52 Location: uk

yeah just a photo of that top board in a ds8 would help a lot Very Happy

like you i guessed the 741 position, dunno about anything else. I only have the schematic from the french site and that might be different?

umschmitt · Posted: Thu Sep 29, 2011 3:01 pm Post subject:

Last minute consideration about DS-7 mods.
It should be better to sum the triangle wave to the square wave instead of switching between them. First because the filter on the triangle makes nearly nothing special (of course), and second it would be a nice feature to be able to boost the fundamental, independently from the action of the filter. Problem is that (I'm pretty sure) both waves are off-phase as is. It'd take an inverting op-amp to do the trick.
(and I had this dream where there was some tremolo available, oooh it was nice)
Besides, the sig-to-trig thing is now more or less working, so I'll start to think about making room on the breadboard and designing the stripboard.
Or do I add one more LM324 ?

feggster · Joined: Sep 12, 2011 Posts: 52 Location: uk

ok, I was given a couple of gutshots of a ds-8 from Marc Bareille (cheers Smile

)
and could work out a lot of the component placement for the add on noise circuit, there is a section in red I could not get a glimpse at! it would be great to work it all out. the 3 sets of wires are for the two pots and the circuit on off switch... someone could add on to the ds-7 stripboard??

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umschmitt · Posted: Tue Oct 18, 2011 3:36 am Post subject:

Well done ! So it was as simple as this… It's nice from Marc, though. What I don't get is that with those DS-8 board pics, you should be able to place every component…
You have two holes unfilled, I'd say they're for a jumper, to allow pins 2 & 6 to connect through the 470k resistor (the vertical unmarked rectangle left of the 741). Note that according to Marc's schem, there should also be a 22p cap across that resistor, to tame the trebles (I don't know much but I think it's usual with 741s). Maybe the engineers at Coron didn't give a f*** about taming any treble whatsoever, just a gang of punks, you see ?
Anyway you simply stick the 22p cap on the solder side and you're done !

feggster · Joined: Sep 12, 2011 Posts: 52 Location: uk

I think you could be right , if you squint looking at the image it looks like a jumper there, I suppose my next step is to build it and see what happens! Smile

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umschmitt · Posted: Sun Oct 23, 2011 7:40 am Post subject:

Yep, looks like a jumper here, and the schemo would agree to this.
(what a stamp you posted !)

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

Can someone confirm that the dual layout posted in this topic works? I made one one this weekend and I'm not getting an output from either side. I can hear the trigger passing thru to the output, and i can hear the VCO and LFO when I monitor other parts of the circuit-- but I guess the VCA isn't working. But it's the same in both sides so either there's a problem w the layout or I must have used a based resistor value somewhere.

I was going to add a switch for two LFO timing caps as someone suggested, a switch for LFO waveforms as illustrated above, and then I thought I'd try to route the LFO to the VCA as a second oscillator.

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

I realized what the prob was, I was only powering and testing one side at a time-- it's necesary for both sides to receive power in order for the 13700 to receive both supplies.

The PCB works great. I'm going to try some of the mods

umschmitt · Posted: Fri Dec 23, 2011 8:12 am Post subject:

Oh ! Happy 100000 views, topic !

feggster · Joined: Sep 12, 2011 Posts: 52 Location: uk

hi again! I am building Uncle Krunkus' stripboard layout of the ds7 and I'm a little confused about the capacitors, which is the correct build of materials for this project?