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Sine suboctave Modul from Scott Bernardi
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Funky40



Joined: Sep 24, 2005
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PostPosted: 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
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PostPosted: Thu Apr 10, 2008 6:19 am    Post subject: Reply with quote  Mark this post and the followings unread

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
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PostPosted: Thu Apr 10, 2008 7:59 am    Post subject: Reply with quote  Mark this post and the followings unread

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
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PostPosted: Thu Apr 10, 2008 12:07 pm    Post subject: Reply with quote  Mark this post and the followings unread

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. Smile

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



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PostPosted: Thu Apr 10, 2008 2:13 pm    Post subject: Reply with quote  Mark this post and the followings unread

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
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PostPosted: Thu Apr 10, 2008 2:17 pm    Post subject: Reply with quote  Mark this post and the followings unread

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



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PostPosted: Sat Apr 12, 2008 5:06 am    Post subject: Reply with quote  Mark this post and the followings unread

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



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PostPosted: Sat Apr 12, 2008 6:50 am    Post subject: Reply with quote  Mark this post and the followings unread

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



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PostPosted: Sat Apr 12, 2008 3:14 pm    Post subject: Reply with quote  Mark this post and the followings unread

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
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PostPosted: Thu Feb 16, 2012 4:46 pm    Post subject: Reply with quote  Mark this post and the followings unread

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.


OG3octaveV3-2.jpg
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3Dview
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OG3octaveV3-2.jpg



OG3octavelayout.pdf
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Layout

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 Filename:  OG3octavelayout.pdf
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OG3octavepcb.pdf
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pcb

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marvkaye



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PostPosted: Fri Feb 17, 2012 5:49 am    Post subject: Reply with quote  Mark this post and the followings unread

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



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PostPosted: Fri Feb 17, 2012 6:10 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks marv

well it's not my first pcb, but it's maybe the second or third one Wink
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.


og3_sine_suboctave_ver22.pdf
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Scott Bernardi original schematic

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Dave Kendall



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PostPosted: Fri Feb 17, 2012 7:29 am    Post subject: Reply with quote  Mark this post and the followings unread

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 Smile

cheers,
Dave

_________________
"The Higgs Bosun's finally been found. So where's the Higgs Captain?"
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marvkaye



Joined: Mar 14, 2011
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PostPosted: Fri Feb 17, 2012 7:48 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanx much, Dave... that Wayback Machine link is perfect. What a cool resource... gotta love the web. Cool

<marv>
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n.d



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PostPosted: Fri Dec 07, 2012 12:53 pm    Post subject: Reply with quote  Mark this post and the followings unread

I`ve just found this backup(?) of his site:

http://www.bernacomp.com/elec/og2/sitemap.html

I also have a pcb layout made by himself (S. Bernardi), double sided, if anybody wants it.
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mph



Joined: Aug 25, 2007
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PostPosted: Sun Dec 16, 2012 5:03 am    Post subject: Reply with quote  Mark this post and the followings unread

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 Wink ).
So people will have the choice Cool
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n.d



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PostPosted: Sun Dec 16, 2012 11:03 am    Post subject: Reply with quote  Mark this post and the followings unread

It´s not as small as you´d think...
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