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umschmitt
Joined: Jun 29, 2011 Posts: 189 Location: brrlin
Audio files: 11
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Posted: Tue Mar 27, 2012 3:05 pm Post subject:
Re: AK47 |
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chguigoz wrote: | What effect has the switch LFO? |
Hey. I think jumunius wrote about this (pages 10-11), search for "UFO" (It's also in M. Bareille's DS-8 schematics, under J7-J10 / S1-S0). _________________ ::U::N::S::C::H::N::E::L::L:: |
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chguigoz
Joined: Mar 02, 2012 Posts: 13 Location: lille france
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umschmitt
Joined: Jun 29, 2011 Posts: 189 Location: brrlin
Audio files: 11
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Posted: Wed Mar 28, 2012 8:35 am Post subject:
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Oops you're right. Then it has to be something else (which I don't get, sorry - bypassing the 3k3 resistor ? what for ?). xpmtl should be able to tell you what. _________________ ::U::N::S::C::H::N::E::L::L:: |
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xpmtl
Joined: Aug 10, 2007 Posts: 162 Location: Brussels, Belgium
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Posted: Wed Mar 28, 2012 10:24 am Post subject:
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the LFO switch simply takes the LFO modulation out of the circuit. The VCO pot doesn't have an effect on the LFO, only the MODE pot has.
A friend has asked me to build him a coron so i'm in the process of doing that based on the schematic I posted. That would allow me to see if there's any problem with it and report back. Waiting on parts, so be patient...
@chguigoz : for your buzz problem, check if you don't have a short to ground somewhere, as dubdummies has the noise part working ok. Also i've compared the noise part in the schematic with the one of Marc Bareille and it's the same. _________________ http://sdiy.xpmtl.net |
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chguigoz
Joined: Mar 02, 2012 Posts: 13 Location: lille france
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Posted: Wed Mar 28, 2012 11:33 am Post subject:
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Hello xpmtl.
I ve seen that your shema was identical to the marc`s shema for the noise parts.
But i'm surprised to see that the load resistor is only 330 ohms!
Therefore, we can only obtain a very low level of noise! The following amp circuit is also designed with a high gain to obtain a sufficient level . On the ds8 i make, i had the same noise level by removing the first transistor and the buzz disapeared.
I will change the value of load and feedback resistors to the same way of the shema I put above. The original design would need a review at this level i think. |
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feggster
Joined: Sep 12, 2011 Posts: 52 Location: uk
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Posted: Sun Apr 01, 2012 5:34 am Post subject:
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if it helps i have a gut shot of an original ds8 and that load resistor is 330r |
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chguigoz
Joined: Mar 02, 2012 Posts: 13 Location: lille france
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Posted: Mon Apr 02, 2012 3:56 am Post subject:
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Hello !
I checked several times components and pcb.
I also made the noise circuit on a stripboard for testing several components(741 and bc547C) and resistors values . It still does not work properly. The noise level is too low.
The highest level I got is putting a zener diode instead the BC547C, change the load resistor to 10k and powered the noise circuit with 9 v .But it is still not sufficient ! I don't understand !!!!
I consoled myself by adding an audio input on my DS7 |
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
Audio files: 26
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chguigoz
Joined: Mar 02, 2012 Posts: 13 Location: lille france
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Posted: Mon Apr 02, 2012 10:39 pm Post subject:
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Thank you. I'll try your circuit. I tried several transistors for the ds8 noise circuit with no success. This is not my first noise circuit but the others module in my eurorack are 12 v powered. I note that the load resistor is 47k instead 330 on the coron. This shema look like my post above except yours is direct coupled between the two transistors .See page 13 |
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chguigoz
Joined: Mar 02, 2012 Posts: 13 Location: lille france
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Posted: Tue Apr 03, 2012 3:35 am Post subject:
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xpmtl wrote: | the LFO switch simply takes the LFO modulation out of the circuit. The VCO pot doesn't have an effect on the LFO, only the MODE pot has.. |
I changed my DS7 by adding the switch on the lfo.
If I do not put the 3k3 resistor, the switch bypasses the lfo.
With this resistor, the waveform of the LFO changes being modulated by the VCO (FM). That's what I noticed and heard by testing. |
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xpmtl
Joined: Aug 10, 2007 Posts: 162 Location: Brussels, Belgium
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Posted: Thu Apr 05, 2012 11:59 am Post subject:
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just a thought, but why would you want to make it working perfectly? Regarding the noise being too low, it's the way that this thing was designed. Design flaw surely, but that's what give it it's character. Change it's characteristics and it won't be a DS8 anymore.
just my 2 cents.... _________________ http://sdiy.xpmtl.net |
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chguigoz
Joined: Mar 02, 2012 Posts: 13 Location: lille france
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Posted: Fri Apr 06, 2012 2:52 am Post subject:
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You are right to say that.
But I first tried the original circuit and I have not got it to work properly. I do not know why. I looked ds8 demonstations on the Web and I have not the same result. The original design for noise seems to me poorly conceived and so I try to make it work otherwise. Maybe the seventie's 741 that I used do not work well in 5 volts, I have to check it. |
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tokyomatik
Joined: Jan 20, 2011 Posts: 171 Location: berlin
Audio files: 6
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Posted: Sun Apr 15, 2012 5:16 pm Post subject:
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finally, after months of debug my DS8 make sounds!!!!
absolute disco flavour!! now i'm happy
i would like to add the cv
and also a led to visualize the lfo rate would be not so bad
anybody tried that?
in wich point of the marc bareille pcb i should try to put the led?
peace |
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tokyomatik
Joined: Jan 20, 2011 Posts: 171 Location: berlin
Audio files: 6
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Posted: Sun Apr 15, 2012 5:24 pm Post subject:
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one last thing, the "pan" between vco and noise it doesn't sound so smoth....
i mean, if i move the pot just slightly from the extreme vco position, then the noise is directly pretty loud and goes louder
i would like to have a more soft transition
i use a linear pot there, should i try with a log? |
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
Audio files: 26
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Posted: Mon Apr 16, 2012 5:24 am Post subject:
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tokyomatik wrote: | one last thing, the "pan" between vco and noise it doesn't sound so smoth....
i mean, if i move the pot just slightly from the extreme vco position, then the noise is directly pretty loud and goes louder
i would like to have a more soft transition
i use a linear pot there, should i try with a log? |
No. You should tweak R34 or add a resistor on the noise side of the pot. _________________ Revenge is a dish best served with a fork... to the eye |
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umschmitt
Joined: Jun 29, 2011 Posts: 189 Location: brrlin
Audio files: 11
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Posted: Mon Apr 16, 2012 10:15 am Post subject:
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tokyomatik wrote: | finally, after months of debug my DS8 make sounds!!!!
absolute disco flavour!! now i'm happy |
That is great news ! IIRC, more people had a similar problem, so it could be valuable if you gave details on how you've had your unit working…
Quote: | i would like to add the cv |
This one shouldn't be a problem.
Quote: | and also a led to visualize the lfo rate would be not so bad
anybody tried that?
in wich point of the marc bareille pcb i should try to put the led? |
This is pretty easy to do, and always nice to have aboard ! You could use a buffer in between, though, in order to leave the outgoing LFO signal unaltered. There's a full topic on the question here :
http://electro-music.com/forum/topic-49449.html
I think J11/LFO3 (M. Bareille's DS-8 layout) would be a good place to take the signal from. _________________ ::U::N::S::C::H::N::E::L::L:: |
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tokyomatik
Joined: Jan 20, 2011 Posts: 171 Location: berlin
Audio files: 6
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Posted: Fri Jun 15, 2012 4:22 am Post subject:
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[quote="umschmitt"] tokyomatik wrote: | finally, after months of debug my DS8 make sounds!!!!
absolute disco flavour!! now i'm happy |
That is great news ! IIRC, more people had a similar problem, so it could be valuable if you gave details on how you've had your unit working…
[quote]ehm....after months of frustration, i spend one afternoon checking really close the board with a google and and trying to fix all the suspect solder joints, i believe it was R27, but i'm not completely sure.
now i'm also trying to buid the ak47 for a friend and to have a working ds8 will be extremely useful in case of debuggin.
apart the led to visualize the lfo rate, i'm wondering if it could be possible to apply some kind of external voltage to the Mode control, would be really useful especially if u use a sequencer, using this function to morph from "kick" sound to something more "metallic"
so, using just one module to have almost a basic "drum kit" Last edited by tokyomatik on Fri Jun 15, 2012 5:35 am; edited 1 time in total |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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Posted: Fri Jun 15, 2012 4:47 am Post subject:
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Sounds great!
I wish I could do an Express PCB layout for this, but I just don't have the time.
I'm startin' a new job on Monday, and things are gonna get crazy for a couple of months. _________________ What makes a space ours, is what we put there, and what we do there. |
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tokyomatik
Joined: Jan 20, 2011 Posts: 171 Location: berlin
Audio files: 6
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Posted: Mon Jun 25, 2012 10:32 pm Post subject:
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finally i finished and tested the ak47 and i have to say that to me sounds even better and louder than the ds8, still trying to understand why the footswitch thing is not working, but should be not a big problem to debug it, also the lfo switch is pretty interesting, kind of "echo/flam" effect.
thanks again for this layout
i love the ak47 and now i'm already thinking about doing one also for me and another one as a gift for a friend
maybe would be not so bad to include the pads for the 68k resistor for the cv in jack....?? |
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feggster
Joined: Sep 12, 2011 Posts: 52 Location: uk
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Posted: Fri Aug 10, 2012 6:30 am Post subject:
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hi, I've built a dual ds7 and its working great! (i used dan's pcb, cheers dan!)
...my question is how do you trigger it with momentary switches? it triggers ok using piezo pads but attaching a momentary switch at the same place doesn't work? any ideas?
edit: page 1 of this thread has the answer |
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umschmitt
Joined: Jun 29, 2011 Posts: 189 Location: brrlin
Audio files: 11
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Posted: Sat Aug 11, 2012 7:12 am Post subject:
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DS-7s respond to an electrical signal or a pulse. In order to trigger them you need current (battery etc) that you'll briefly - or not - let flow to the triggering input of the DS-7 with the momentary switch. If it has to be brief, I'd put a cap on the way. That being said, manual (or footal) triggering works very well with piezos. _________________ ::U::N::S::C::H::N::E::L::L:: |
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xpmtl
Joined: Aug 10, 2007 Posts: 162 Location: Brussels, Belgium
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Posted: Tue Aug 14, 2012 2:12 am Post subject:
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Just to report I built a DS8 clone for my friend's Bday following the schematic I posted a few pages back.
Two things to note, footswitch doesn't work and the noise balance pot doesn't sound too good (noise comes in too abruptly, not smooth at all). I'll have to look into these problems but right now i'm too busy building my modular so it will have to wait.
Other than those two problems everything else works fine.
So for the peeps having problems with the rest of the circuit, check your builds it must be an error on your side.
hope this helps,
x _________________ http://sdiy.xpmtl.net |
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feggster
Joined: Sep 12, 2011 Posts: 52 Location: uk
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Posted: Tue Aug 14, 2012 5:02 am Post subject:
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thanks umschmitt, I used the method described on page 1 it works fine with a momentary switch and a 1meg resistor to +9v.
to xpmtl, I'll have a go at building the ak47 soon, would a linear pot help with the lfo noise mix? I can live without the footswitch..I never understood it, also I have an original ds7 and the footswitch doesnt work |
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xpmtl
Joined: Aug 10, 2007 Posts: 162 Location: Brussels, Belgium
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Posted: Tue Aug 14, 2012 9:04 am Post subject:
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ah, well observed feggster, now that you mention it, a linear pot would have been be more logical there.
No idea why they have put a log one in the first place. Another oddity of this circuit i guess..
As far as i can remember the footswitch on the original DS8 i cloned wasn't working either _________________ http://sdiy.xpmtl.net |
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o-live
Joined: Aug 14, 2012 Posts: 25 Location: france
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Posted: Tue Aug 14, 2012 5:04 pm Post subject:
part list |
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hello
i'm really interested to buy my first ds-8 but i don't find the part list for the
version of ds8 with lm13700 ota
where i can found it please ?
good continuation |
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