electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software » The layout factory
basic volt per octave keyboard schematics
Post new topic   Reply to topic
Page 2 of 7 [165 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Goto page: Previous 1, 2, 3, 4, 5, 6, 7 Next
Author Message
Grumble



Joined: Nov 23, 2015
Posts: 1294
Location: Netherlands
Audio files: 30

PostPosted: Fri Apr 15, 2016 9:14 am    Post subject:   Reply with quote  Mark this post and the followings unread

Good idea!
Back to top
View user's profile Send private message Visit poster's website
blue hell
Site Admin


Joined: Apr 03, 2004
Posts: 24079
Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320

PostPosted: Sat Apr 16, 2016 2:38 am    Post subject: Reply with quote  Mark this post and the followings unread

Cfish wrote:
I wanted to post this Ken stone schematic here in case anyone wants to try it out. [...] It worked ok but had a little key lag.


The capacitors on pin 5 and 6 (for scan oscillator frequency and key bounce elimination) seem to be on the large side.

I'll make this thread a sticky one.

_________________
Jan
also .. could someone please turn down the thermostat a bit.
Posted Image, might have been reduced in size. Click Image to view fullscreen.
Back to top
View user's profile Send private message Visit poster's website
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Sat Apr 16, 2016 6:41 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks for the recommendation. I will do some experimentation with that. Do you have a recommended start point?
Back to top
View user's profile Send private message
blue hell
Site Admin


Joined: Apr 03, 2004
Posts: 24079
Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320

PostPosted: Sat Apr 16, 2016 6:51 am    Post subject: Reply with quote  Mark this post and the followings unread

I saw the datasheet has some timing equations .. generally for switches you want a debounce time of 50 ms or so , but this may be a bit long still for musical applications, it will depend on the actual switches.
_________________
Jan
also .. could someone please turn down the thermostat a bit.
Posted Image, might have been reduced in size. Click Image to view fullscreen.
Back to top
View user's profile Send private message Visit poster's website
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Sat Apr 16, 2016 12:00 pm    Post subject: Reply with quote  Mark this post and the followings unread

Thanks. I will go with the (small jumps till the bounce starts to show up ) and see what happens. Thanks for your time on this. would be nice to post minor mods that might make it a little more useful. It makes a nice little test keyboard for the work bench the way it is.
Back to top
View user's profile Send private message
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Sun Apr 17, 2016 9:44 am    Post subject: Reply with quote  Mark this post and the followings unread

Figured I would go ahead and post Grumbles volt per octave circuit with the gate comparator.

I used 741 op-amps and it worked well.


image.jpeg
 Description:
 Filesize:  1.05 MB
 Viewed:  1385 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

image.jpeg


Back to top
View user's profile Send private message
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Wed Apr 27, 2016 12:18 pm    Post subject: Reply with quote  Mark this post and the followings unread

As with the first schematic on this page, I had an improvement in temperature stability with Grumbles circuit when using OP177 opamps

These things are impresive. I finally had the heat gun out trying to get a drift I could register.
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Sun Sep 04, 2016 2:41 pm    Post subject: Reply with quote  Mark this post and the followings unread

hello everybody

i breadboarded Grumble's project yesterday, but no luck whatsoever. Confused Confused

I am interested in building a basic CV gate keyboard circuit, so that i can control a simple VCO-VCF-VCA architecture with a ADSR envelope controlling the vca.

Despite assembling the above modules and Grumble's circuit,though, i only got a constantly ON vco signal.
any suggestion? many thanks to all Mr. Green
Back to top
View user's profile Send private message
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Sun Sep 04, 2016 4:21 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Alenwilder81. Are you saying that you get a constant on gate signal? If that's the case. The 100k trim on the schematic I drew is very touchy.

If you increase the value of the resistor at the bottom of the resistor chain, the one that ties to ground. It will increase the span between key up and the lowest key press. Which makes it much less touchy to adjust the gate comparator trim. I think I have 1k 2. There in my current version. Giving about 1 octave of span between key up and the lowest key press.

I also installed a pull down resistor at the gate output. Think it was 150k to ground. Otherwise one of my VCAs that has an AC blocking capicitor on its input would charge the cap and act like a sample and hold circuit.

Will try to help all I can.

I have this circuit up and working as drawn but am working on something to fix a drift in note span that shows up when I use it on my full keyboard.

Works good in my 13 note bass pedal synth and an 18 note small keyboard I built to test things on the bench.
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Sun Sep 04, 2016 5:25 pm    Post subject: Reply with quote  Mark this post and the followings unread

hey Cfish,
thanks for promptly coming back to me.
I saw the video on You Tube showing you play that bass pedal.
very nice fat sound, indeed. Razz

As far as my project,well...
at the moment i am a bit confused as to what the culprit is.
in all fairness, it's the very first time i even try to put VCO, VCF, VCA, plus ADSR and keyboard controller together.

i am only sure about VCO and VCF properly working,having tested them for long time, by now.
Troubles arouse when a couple of days ago i added an ADSR found on "fonitronik modular synth DIY" site, and a simple VCA found on "Yusynth".

They looked simple enough,so, i breadborded them, connected as well as i could with the other modules, but with sloppy resoults.

chanches are i probably made any mistake when patching modules to one another. Or, is a VCA or ADSR issue. or even a keyboard circuit problem.

To narrow things down, for a start,i better get you the patching diagram i followed to get the modules together to make sure wether is right or not. in either case,i'll give my project another deeper look to try and troubleshoot the whole thing. I'll tell you as soon as i do that.

thanks a lot for your time, ill keep you posted Smile Smile Smile
Back to top
View user's profile Send private message
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Sun Sep 04, 2016 5:45 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Alanwilder81

If you could include links to the schematics you used on your ADSR and VCA when you send your patch, it might be helpful.

Are you building this as a modular? Or is your ADSR hard wired between the keyboard gate signal and VCA?

Would love to see a pic. Of your project.
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Sun Sep 04, 2016 6:26 pm    Post subject: Reply with quote  Mark this post and the followings unread

hey Cfish,

i am starting really small,no modular dreams whatsoever Very Happy .
Also,i am a big fan of the hardwired classic early monosynths architecture,the likes of Korg 700s or Arp Odissey,you name it.

I'd like to start to get grasp with the classic VCO-VCF-VCA architecture, to get familiar with the signal chain. As a DIY total newbie,i thought it'b better to embark on an extremely simple design, to move the first baby steps safely if you know what i mean Smile

I will provide you with the links altogether,so you can tell what's what. And a hand drawn diagram as well.

Please excuse my rusty english grammar and my noob questions eheheheh.
I am now going to bed,it's late night in italy. Tomorrow i will go back to the project and send you some more material, as promised.

Again, thanks a lot for the support. Mr. Green Mr. Green Mr. Green
Back to top
View user's profile Send private message
Grumble



Joined: Nov 23, 2015
Posts: 1294
Location: Netherlands
Audio files: 30

PostPosted: Mon Sep 05, 2016 12:02 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi alanwilder81

"My" Project was a little exercise in analog design, as I wrote in the picture: "NOT TESTED! Just for considering..."
Cfish was so kind and knowledgeable to got it working (Thanks Cfish)
I hope you have your answers, happy building Laughing
Back to top
View user's profile Send private message Visit poster's website
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Mon Sep 05, 2016 4:32 am    Post subject: Reply with quote  Mark this post and the followings unread

thanks Grumble,

according to Cfish that module works,it probably needs some more tweaks but it does the job right Razz Razz
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Mon Sep 05, 2016 5:15 am    Post subject: Reply with quote  Mark this post and the followings unread

to Cfish,

as promised, here are the links of the modules i am trying to patch together.

VCO,works like charm:

http://yusynth.net/gear/US1/images/VCO-US1.gif



VCF,perfect:

http://www.modular.fonik.de/files/EFMforum/orgEFMfiles/3500er/3528_VCF2.pdf


VCA:

http://www.modular.fonik.de/files/EFMforum/orgEFMfiles/3500er/3531_VCA.pdf


ADSR:

http://www.modular.fonik.de/files/EFMforum/orgEFMfiles/3500er/3508_ADSR.pdf

So, along with doing the little tweaks you suggest for your keyboard circuit,
i might need a correct patching diagram to get those modules to work together. Like, the keyb to control the pitch of the VCO , and the ADSR to control both VCA and VCF. simple stuff in theory,if rightly connected Very Happy

cheers
Back to top
View user's profile Send private message
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Tue Sep 06, 2016 5:21 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi alanwilder81
I like that VCO schematic. I took one look at it and started one of my owne.

It looks a lot like a Thomas Henrey 555 VCO leaving out a lot of the extra Amenities.

I didn't look a lot farther. But if you patch the pitch out on grumbles circuit in to the CV in on your VCO, it should cause pitch change on your VCO with key presses. Should then return to the open note resistor chain setting on key release.

The trim on the top left opamp in grumbles schematic is then adjusted to get one volt of change per one octave of change. Or you could just adjust it till you get one octave of real pitch change. I don't have any of mine set at exactly one volt per octave.

One volt per octave exactly only needs to be adjusted in if you are going to join, or commonly switch the VCO you use.

Otherwise, make it sound right.

Then use a volt meater to check the gate out I added. Adjust the trim on the gate opamp. With no keys pressed, adjust trim untill voltage just goes negative. As you sweep the trimmer you should find the point where it switches. Set it just a touch below where it goes negative. Then adjust till the lowest key press switches voltage to positive. That is it.

The biggest problem I had with this circuit is temperature drift. When the opamps are cold. First turned on. Gate would switch on untill they warm up

I made a reference to the opamps I used to help this problem somewhere in this article. Don't remember exactly what they were off the top of my head.

Let me know if that helps with this part of your project.


Thank you so much for the compliment Grumble.

In reality, I am proof that a person with very poor math skills limited to basic arithmetic.. Can accomplish really cool things if you don't mind taking the time to experiment a lot.
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Tue Sep 06, 2016 6:09 am    Post subject: Reply with quote  Mark this post and the followings unread

hi Cfish

you made a great point by stating

"In reality, I am proof that a person with very poor math skills limited to basic arithmetic.. Can accomplish really cool things if you don't mind taking the time to experiment a lot"

i couldn't agree more with you!!

I am far from being EE or electronics knowledgeable at all,i only know the very basics. Yet.with a lot of passion, hard studying, work,reading and thinking, i've been able to pull out gorgeous modules.
And that's just scratching the surface. A whole new world opens up with DIY synthesizers.

And the and pride of making yourself VCOs and VCFs, something only some time ago i could only dream of.Priceless Smile

That's the spirit. Let's all work together and support each other as a team. We can achieve the Wink Wink unthinkable
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Tue Sep 06, 2016 6:13 am    Post subject: Reply with quote  Mark this post and the followings unread

to Cfish,

As for the Grumble's module, I haven't had time to take a deeper look at the module, as i am busy with work. I will as soon as possible.
Thanks for the advices and suggestions Very Happy
Back to top
View user's profile Send private message
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Thu Sep 08, 2016 4:15 am    Post subject: Reply with quote  Mark this post and the followings unread

My summer work hours being around 70 hrs a week have left me with very little project time.

Alanwilder81s interest in this project reminded me that I had written down a few pages about my experience with it.

I had intended on doing a YouTube video showing my results and conclusions, but was still trying to remedy some glitches before I did.

Time has kept that from happening at the moment.

So I thought that I should point out that along with the othe adjustments and add ons I tried on grumbles schematic. It works great out to 2 octaves.

However I ran in to problems with the volt per octave trim response not being totally linear.

When I used it on my full keyboard I could only get about 2 octaves in tune. Then the notes would glide up in pitch as the note went down the scale.

I have a few drawings of ideas to minimize this, but haven't had time to try them out.

In my opinion all 3 circuits listed in this thread are worth building and experimenting with.

But don't expect a Ray Willson CV controller Right out the gate.

These all give great platforms to build on.

HAPPY BUILDING! And KEEP EXPERIMENTING!!
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Thu Sep 08, 2016 5:15 am    Post subject: Reply with quote  Mark this post and the followings unread

hello dear Cfish,

yes, work can really suck your energies and time, with little time left for the hobbies Very Happy
I've been thinking to build an actual keyboard CV GATE TRIGGER circuit found on Yves Usson website.

The circuit is confirmed to be flawless and perfectly tested by Yves Usson himself, who i swapped two messages with, a couple of days ago.

here it's the link:

http://yusynth.net/index_en.php?&arg=1

it's a collection of old articles and circuit schematics. You'll find that amazing keyb circuit on the very bottom page, as last article.

It's called "Student project supervised by T. Rochebois : building a small analogue synth". Just click onto the french flag and the link will open to that project.

Well, you mentioned the Ray Wilson's project..well.. that's beyond complex, extremely high components count and not an easy build.

Whereas the keyb project i got you the link of, is much simpler than Ray Wilson's and according to Yves, works like charm.

Ive already thanked Yves for that. hope it helps Cool
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Thu Sep 08, 2016 5:23 am    Post subject: Reply with quote  Mark this post and the followings unread

to Cfish

it looks too good to be true, a simple circuit that spits out CV, GATE, TRIGGER, that is able to get us a nice control over our modules.
I hope to get some missing components to start to build it,like the CD4066 and the LM 393. i cant wait to get hold of them.

give it a go,it is absolutlely guaranteed to be working.

Hope we can share some degree of success very soon Very Happy Very Happy
Back to top
View user's profile Send private message
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Thu Sep 15, 2016 5:36 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi alanwilder81

Let us know how that one works out for you. If you could include a direct screenshot of the schematic you use, with credit to its creator. Others could benefit.

Most people use digital to scan the key press now days. If I was looking at the right one at the link you poasted. It appeared to be digital.

Staying with analog in most of my projects was more of a personal challenge.

I wanted to truly understand how it was done in the beginning before I move on to the digital realm.
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Thu Sep 15, 2016 7:16 am    Post subject: Reply with quote  Mark this post and the followings unread

hey c fish,

i thought that keyboard design was fully analog. Why digital?
i assumed it wasnt digital at all, i might be wrong
Back to top
View user's profile Send private message
Cfish



Joined: Feb 24, 2016
Posts: 477
Location: Indiana

PostPosted: Thu Sep 15, 2016 5:03 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi allenwilder81.
I may have ben looking at the wrong one. There was a lot of good things on that link.

That's why I asked if you could post the schematic you are using, and let us all know how it works for you.

Edit. That sounded like I was trying to sound snooty, I wasn't.

I'm excited to have a new idea to try.

We're so many ideas in the link I got lost.
Back to top
View user's profile Send private message
alanwilder81



Joined: Sep 03, 2016
Posts: 310
Location: italy

PostPosted: Fri Sep 16, 2016 8:05 am    Post subject: Reply with quote  Mark this post and the followings unread

to cfish,
cool that you found inspiring material on the Yusynth site.I also take huge inspiration from that
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic
Page 2 of 7 [165 Posts]
View unread posts
View new posts in the last week
Goto page: Previous 1, 2, 3, 4, 5, 6, 7 Next
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » The layout factory
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use