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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
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G2 patch files: 5
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Posted: Thu Apr 10, 2008 5:45 am Post subject:
Sine suboctave Modul from Scott Bernardi Subject description: I nee some help to draw a Board |
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Hello,
i'm on the way to draw a Board for the sine suboctave modul from Scott Bernardi,
and i need a littlebit of Help:
here the schematic ( link is on the Bottom )
http://home.comcast.net/~sbernardi/elec/og2/og3_sine_suboctave.html
Does IC one =U6 needs to be a TL071 ? ( see top left corner )
this is complicating up my drawing very much.
It looks to me as he has the trimm outs anyway not connected.
Can i go for a TL 072 for U6 ?
thanks. |
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françois
Joined: Dec 23, 2006 Posts: 139 Location: Paris (France)
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Posted: Thu Apr 10, 2008 6:19 am Post subject:
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Hello,
I think Scott is using a TL071 just because all four opamps in a TL074 are already in use. There is in principle no difference between a TL071 (single), a TL072 (dual) and a TL074 (quad) as far as the opamps are concerned (I mean, they have identical characteristics).
It is a pity that autorouting software are not able (AFAIK) to take into account that the four amps in a TL074 are interchangeable and use this fact to optimize routing. This would certainly require a lot of AI, but is it really impossible ?
Now you sure may use half of a TL072 for U6. Just be sure to "neutralize" the unused one, e.g. by connecting it as a voltage follower with the (+) input wired to ground, or you're likely to get parasitic signals in weird places.
Yours,
-- françois |
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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
Audio files: 1
G2 patch files: 5
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Posted: Thu Apr 10, 2008 7:59 am Post subject:
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françois wrote: | Hello,
Now you sure may use half of a TL072 for U6. Just be sure to "neutralize" the unused one, e.g. by connecting it as a voltage follower with the (+) input wired to ground, or you're likely to get parasitic signals in weird places.
Yours,
-- françois |
thank you Francois,
ok, i will then continue drawing with Dual OP amps.
I don't draw anymore with quad OPamps ( TL 074) because the dual ones can be changed by better ones if required.
Yeah, i learned the last Weeks thanks to EM that unused OP amps must be "neutralized"
i should then be able to layout a Board for this Module.
As it seems does my Friend etch next Week for me,
so i must hurry.
( i most wait sometimes many month ) |
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Peake
Joined: Jun 29, 2007 Posts: 1113 Location: Loss Angeles
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Posted: Thu Apr 10, 2008 12:07 pm Post subject:
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Brilliant. Thanks for the note in my thread regarding this. Will it be a publicly available PCB, or are you going to post artwork, or? I'd love to see a breadboard suggestion if you are willing to share your results.
I'd forgotten that Mr. Bernardi's design had saws. Or it was bugging me from the back of my mind.
I imagine that you can take a suboctave and create PWM from it...Use a separate LFO and it should sound rather thick. (Mike Brown's AFG has started my head going.) |
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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
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G2 patch files: 5
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Posted: Thu Apr 10, 2008 2:13 pm Post subject:
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i will not do PCb runs as i have no experience with this + orther factors.
If i ever get a Board running i can share my work ofcourse. |
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françois
Joined: Dec 23, 2006 Posts: 139 Location: Paris (France)
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Posted: Thu Apr 10, 2008 2:17 pm Post subject:
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Peake wrote: | I imagine that you can take a suboctave and create PWM from it...Use a separate LFO and it should sound rather thick. (Mike Brown's AFG has started my head going.) |
Sure you can. And you ought to. This is what I had in mind when designing a f×2 / f×3 / f×5 / f÷2 / f÷3 / f÷5 (up or down one octave, one major fifth, one major third) generator. Sawtooth already has all harmonics (odd & even) so adding sub- or super-octave or other intervals is not as interesting as it would seem at first. But when re-transforming the derivated sawtooths through various waveshapers (including PWM of course) it gets really _phat_.
-- françois |
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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
Audio files: 1
G2 patch files: 5
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Posted: Sat Apr 12, 2008 5:06 am Post subject:
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quotet from Peaks thread:
http://www.electro-music.com/forum/posting.php?mode=quote&p=179572
françois wrote: | richardc64 wrote: | http://home.comcast.net/~sbernardi/elec/og2/og3_sine_suboctave.html |
Interesting, and very similar to my design. The ony differnce is that mine was only SPICE tested, not even breadboarded... But even so, it has glitches (spikes) at every reset of the input saw. These are normally not audible, but can be removed (to a large amound) by adding a small (say, 100p) cap across the feedback resistore at U1.
-- françois |
Do you mean U1B, across R14 and R16 ?
U1A and U1C has 56pF, U1D has 100pF, but U1B has nothing, and it has two feedbackpathes |
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françois
Joined: Dec 23, 2006 Posts: 139 Location: Paris (France)
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Posted: Sat Apr 12, 2008 6:50 am Post subject:
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Funky40 wrote: | Do you mean U1B, across R14 and R16 ?
U1A and U1C has 56pF, U1D has 100pF, but U1B has nothing, and it has two feedbackpathes |
I was referring to my own design. In Scott Bernardi's design, U1B doesn't need a compensation capacitor, I think. If you put one, insert it between pin 7 (output) and pin 6 (inverting input).
-- françois |
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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
Audio files: 1
G2 patch files: 5
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Posted: Sat Apr 12, 2008 3:14 pm Post subject:
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thank you Francois
it's not easy to draw this Module.
i got in the Meantime pics from a layout which was somewhere posted, but was then removed.
Also that one is somewaht ...hmmm....with many wireBridges.
really not easy. |
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mph
Joined: Aug 25, 2007 Posts: 87 Location: France
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Posted: Thu Feb 16, 2012 4:46 pm Post subject:
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Hello
I've done a layout for a pcb, thanks to Jerem (from the french Yusynth forum) who pointed out many errors and who built first this one.
So it is verified.
You should notice that P6 on the schemo seems to be drawn in the wrong sense, you should tie pin 2 & 3 together and NOT pin 1 & 2. This pot is really tricky to me as it doesn't act like a simple attenuator.
Here is the files, pcb + layout. Please pay attention to the jumpers J1 to J4.
And feel free to suggest or comment this one. It is some of my very first pcb design.
Thanks!
edit: added a 3D view, just for fun.
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This image has been reduced to fit the page. Click on it to enlarge. |
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OG3octavelayout.pdf |
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298 Time(s) |
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OG3octavepcb.pdf |
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38.94 KB |
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255 Time(s) |
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marvkaye
Joined: Mar 14, 2011 Posts: 225 Location: Fla
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Posted: Fri Feb 17, 2012 5:49 am Post subject:
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Nice layout, hard to believe it's your first attempt. I wanted to see the original schematic but the comcast link in the first post is dead. Is there a new address available, or do you have a copy you could post (with the proper disclaimers for whose work it is, etc)? Thanx
<marv> |
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mph
Joined: Aug 25, 2007 Posts: 87 Location: France
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Posted: Fri Feb 17, 2012 6:10 am Post subject:
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Thanks marv
well it's not my first pcb, but it's maybe the second or third one
Anyway I use to work on perfboard for a long time so it certainly helped me a lot, and I've made lot of mistakes during the drawing so I've also learned a lot while doing this.
On this schemo you should read potentiometers pins 321 from left to right for the output waveforms, but P6 is reversed so you should read 123 from left to right.
Note that all the waveform pots are not drawn in the last page of this document, but they are all present in my layout. So in total there are 10 pots, 1 SPDT switch and 2 jacks.
Here is also a quote from Mr. Bernardi's dead website concerning adjustment procedure:
Quote: | "Trimming:
There are two trimmers per stage. Looking at the output of U1:8 on a scope, adjust RV3 to get the best looking triangle. Then look at the output of U1:14,, and adjust RV1 for the best looking sine. Perform the same operation on the second stage by looking at U5:8 and adjusting RV4 for best triangle, and at U5:14 and adjusting RV2 for best sine.
I also found that R11 could be tweaked to give the best looking saw at U1:1. I ended up soldering a 1Meg resistor in parallel with R11 to give a straighter ramp in the -1 octave sawtooth." |
I've tried to get in touch with him with no succes, I suppose he's ok. If it's not the case I would remove everything asap of course.
Description: |
Scott Bernardi original schematic |
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og3_sine_suboctave_ver22.pdf |
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19.57 KB |
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236 Time(s) |
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Dave Kendall
Joined: May 26, 2007 Posts: 421 Location: England
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Posted: Fri Feb 17, 2012 7:29 am Post subject:
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Hi Guys.
I've recently been in contact with another SDIY'er who has been attempting to contact Scott Bernadi, to ask for permission to host the files on his site. So far he has been unable to contact Mr B.
IIRC, Mr B decided a few years back to concentrate on his religious activities, so he may not be doing any SDIY any more.....
Some stuff is still on the OG2 site, and I saved most of the rest for personal use a few years back. If anyone needs something specific, PM me. I think it would be OK for me to send this stuff for someone using it for personal use, as the schematics were freely published and many are still on the site.
There are a few different hits on the wayback machine - this one seems the best....
http://web.archive.org/web/20030808154256/http://home.comcast.net/~sbernardi/elec/og2/sitemap.html
Hope this helps
cheers,
Dave _________________ "Everything in moderation, including moderation" |
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marvkaye
Joined: Mar 14, 2011 Posts: 225 Location: Fla
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Posted: Fri Feb 17, 2012 7:48 am Post subject:
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Thanx much, Dave... that Wayback Machine link is perfect. What a cool resource... gotta love the web.
<marv> |
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n.d
Joined: Dec 15, 2011 Posts: 52 Location: Talos IV
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mph
Joined: Aug 25, 2007 Posts: 87 Location: France
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Posted: Sun Dec 16, 2012 5:03 am Post subject:
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Thanks for the link n.d
Yes a double sided pcb would be cool to fit a tiny modular setup if you can post the pdf file.
However I have to say my single sided version is fully functional too (and can be easily etched at home ).
So people will have the choice |
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n.d
Joined: Dec 15, 2011 Posts: 52 Location: Talos IV
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Posted: Sun Dec 16, 2012 11:03 am Post subject:
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It´s not as small as you´d think... |
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