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
LFO Delay
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [22 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
211



Joined: Jul 18, 2006
Posts: 50
Location: Marseille - France

PostPosted: Mon Feb 19, 2007 4:36 am    Post subject: LFO Delay Reply with quote  Mark this post and the followings unread

Hi all,

Does anyone build this LFO delay with success ?
Posted Image, might have been reduced in size. Click Image to view fullscreen.

I just built it, with BC547/557 trannies and +15-15 powered, and it don't work at all...

I can see C2 1uF caps discharge on gate, but nothing after R2.
My LFO (initially +5/-5v) output voltage is stuck to +0,5/-0,5 but don't raise to +5/-5 when C2 is discharged..

Any idea ? Do I need to change R2 resistor value to fit with my power supply or BC557 properties ?

thanks !
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1176
Location: australia
Audio files: 4

PostPosted: Mon Feb 19, 2007 8:02 am    Post subject: Reply with quote  Mark this post and the followings unread

This is one of Kunii San's (aka Masa 921), a master of minimal circuit design.
I built it a few years back, no probs (not that I remember )
I think it was meant to be an add-on for his LFO.

The transistors are nothing special -I've used C1815(npn) and A1015(pnp) for nearly every CGS circuit with no trouble or mods(other than different pinout). Also I used -15V with this.
The synth, it lives in, is in storage now so I can't get to it to check anything.

If you're sure all connections and orientations are good, I guess R2 is the place to start experimenting.
Masa921 is not much good at English but if you are stuck I can check with the guys at Japanese synth-diy for some hints.

I can't resist posting this pic - Masa921 microVCO, no chips just 5 transistors and 2 FETs, V/Hz and V/oct control and it sounds awesome, very meaty. Thats the whole cct in a blob of goop. He bought it to a diy meeting, hooked it up and started playing. everyone was pretty stunned by the quality (and the size)
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
funkyfarm



Joined: Jan 21, 2007
Posts: 583
Location: France
Audio files: 3

PostPosted: Mon Feb 19, 2007 8:33 am    Post subject: Re: LFO Delay Reply with quote  Mark this post and the followings unread

211 wrote:
Hi all,

Does anyone build this LFO delay with success ?


This is a cheap design as it obviously doesn't reset your LFO waveform.
So, after delay time being elapsed, the LFO doesn't start from zero...
Back to top
View user's profile Send private message
211



Joined: Jul 18, 2006
Posts: 50
Location: Marseille - France

PostPosted: Mon Feb 19, 2007 8:57 am    Post subject: Reply with quote  Mark this post and the followings unread

This design is the same as MC202 LFO . I connected my LFO in the same way.. I checked trannies pinout with eagle before assembly..

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Now, as andrewF has already built it, I m sure that design may works..
I probably missed something...
Back to top
View user's profile Send private message
211



Joined: Jul 18, 2006
Posts: 50
Location: Marseille - France

PostPosted: Mon Feb 19, 2007 3:31 pm    Post subject: Reply with quote  Mark this post and the followings unread

that's ok, it works fine ! ( was a bad connection )
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: Mon Feb 19, 2007 6:43 pm    Post subject: Reply with quote  Mark this post and the followings unread

211 wrote:
that's ok, it works fine ! ( was a bad connection )


Makes sense, good you found it Smile

_________________
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
sneakthief



Joined: Jul 24, 2006
Posts: 569
Location: Berlin

PostPosted: Tue Feb 20, 2007 5:07 am    Post subject: Reply with quote  Mark this post and the followings unread

andrewF - I was looking through Masa921's site and couldn't find the schematics for the microVCO. Are they available online anywhere?

thanks!

_________________
Sneak-Thief - raw electrofunk
Back to top
View user's profile Send private message Visit poster's website
211



Joined: Jul 18, 2006
Posts: 50
Location: Marseille - France

PostPosted: Tue Feb 20, 2007 6:08 am    Post subject: Reply with quote  Mark this post and the followings unread

http://masa921.hp.infoseek.co.jp/synth2.htm

But there's no schematics..

It's Korg MS 10/20/50 design I guess.
2 2SK30 FET / 2SA733 2SC945 transistors.

Expo converter is 2SC1583 based, Volt/oct & Volt/hertz control and output easily tri and square signals.

Does anyone test this design ? Is it stable enough ?
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1176
Location: australia
Audio files: 4

PostPosted: Tue Feb 20, 2007 6:56 am    Post subject: Reply with quote  Mark this post and the followings unread

Masa921 used some different transistors for this design. I have no idea how you would go with substituting, the FETs are probably the fussiest.
There are some amazing pics on the link above provided by 211- why use circuit boards when you have a blob of goop?
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
sneakthief



Joined: Jul 24, 2006
Posts: 569
Location: Berlin

PostPosted: Tue Feb 20, 2007 1:44 pm    Post subject: Reply with quote  Mark this post and the followings unread

thanks!!! i'd love to try this sometime.
_________________
Sneak-Thief - raw electrofunk
Back to top
View user's profile Send private message Visit poster's website
fonik



Joined: Jun 07, 2006
Posts: 3950
Location: Germany
Audio files: 23

PostPosted: Tue Feb 20, 2007 2:55 pm    Post subject: Reply with quote  Mark this post and the followings unread

oha, these transistors seem very exotic to europeans, i think. i bet they are hard to find!
_________________
Posted Image, might have been reduced in size. Click Image to view fullscreen.
cheers,
matthias
____________
Big Boss at fonitronik
Tech Buddy at Random*Source
Back to top
View user's profile Send private message Send e-mail Visit poster's website
23isgood



Joined: Nov 18, 2006
Posts: 236
Location: San Francisco, CA bay area
Audio files: 13

PostPosted: Tue Feb 20, 2007 4:05 pm    Post subject: Reply with quote  Mark this post and the followings unread

Wow nice! So does this micro VCO perform as well as a typical VCO?
Back to top
View user's profile Send private message Visit poster's website
23isgood



Joined: Nov 18, 2006
Posts: 236
Location: San Francisco, CA bay area
Audio files: 13

PostPosted: Tue Feb 20, 2007 8:15 pm    Post subject: Reply with quote  Mark this post and the followings unread

What does the upward pointing black arrow supposed to go to? The one labeled "BIAS"? Is this supposed to be connecting to -12v? Will some resistors be enough to take +-15v down to +-12v?

thanks
pete
Back to top
View user's profile Send private message Visit poster's website
andrewF



Joined: Dec 29, 2006
Posts: 1176
Location: australia
Audio files: 4

PostPosted: Wed Feb 21, 2007 12:19 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi
I was impressed with the sound of this cct but i only heard it for a few minutes.
doubt it will be as stable as a typical VCO, no temperature compensation for a start. Maybe if you used the V/hz input it would be okay.
i suspect the reason the entire cct is built into a little compact blob is so all the transistors can warm up to the same temp and attain some stability, like the EFM chip heater VCO perhaps.

it is a very basic cct, don't expect too much from it. If you already have one or more wizzbang VCOs, this would be a good supplement.

it runs on +12V, +6V and Gnd.
Generally, it would be better to use 7812 and 7806 voltage regulators rather than resistors (with resistor dividers - as the current increases, the voltage changes).
That said, if you are breadboarding, try a resistor divider, it might prove interesting...or not Wink
Back to top
View user's profile Send private message Visit poster's website
23isgood



Joined: Nov 18, 2006
Posts: 236
Location: San Francisco, CA bay area
Audio files: 13

PostPosted: Wed Feb 21, 2007 12:37 am    Post subject: Reply with quote  Mark this post and the followings unread

Well I have plenty VCO's but I really want to build a small compact synth that is portable and this VCO would be a nice addition. With a few pic modules it could happen.

thanks
pete
Back to top
View user's profile Send private message Visit poster's website
janvanvolt



Joined: Nov 24, 2005
Posts: 285
Location: Mainz, Germany

PostPosted: Wed Feb 21, 2007 11:01 am    Post subject: Reply with quote  Mark this post and the followings unread

fonik wrote:
oha, these transistors seem very exotic to europeans, i think. i bet they are hard to find!


the 2SA and 2SC types are sold by reichelt
the 2SK is sold by banzai.

just ordered mine ...

just as of the design, do i get this right:

- LIN CV jack in
- HARDSYNC jack in
- Oct/V CV jack IN
- VCO jack out

- Pot for COARSE ? (below Oct/V)
- pot for LIN CV

anything i missed ?
Back to top
View user's profile Send private message Visit poster's website AIM Address
fonik



Joined: Jun 07, 2006
Posts: 3950
Location: Germany
Audio files: 23

PostPosted: Wed Feb 21, 2007 11:49 am    Post subject: Reply with quote  Mark this post and the followings unread

okay - not exotic.
_________________
Posted Image, might have been reduced in size. Click Image to view fullscreen.
cheers,
matthias
____________
Big Boss at fonitronik
Tech Buddy at Random*Source
Back to top
View user's profile Send private message Send e-mail Visit poster's website
etaoin



Joined: Jun 30, 2005
Posts: 761
Location: Utrecht, NL

PostPosted: Wed Feb 21, 2007 12:18 pm    Post subject: Reply with quote  Mark this post and the followings unread

Quote:

the 2SA and 2SC types are sold by reichelt


You might not know this, as you are in Germany, but Reichelt have a minimum order of 150 euros outside of Germany. So they're actually very expensive just to get a couple of trannies.
Back to top
View user's profile Send private message Visit poster's website MSN Messenger
janvanvolt



Joined: Nov 24, 2005
Posts: 285
Location: Mainz, Germany

PostPosted: Wed Feb 21, 2007 12:48 pm    Post subject: Reply with quote  Mark this post and the followings unread

Etaoin wrote:

You might not know this, as you are in Germany, but Reichelt have a minimum order of 150 euros outside of Germany. So they're actually very expensive just to get a couple of trannies.


Well. If somebody want's to do a groupbuy, i can handle this.
Back to top
View user's profile Send private message Visit poster's website AIM Address
andrewF



Joined: Dec 29, 2006
Posts: 1176
Location: australia
Audio files: 4

PostPosted: Wed Feb 21, 2007 3:47 pm    Post subject: Reply with quote  Mark this post and the followings unread

Quote:



- LIN CV jack in
- HARDSYNC jack in
- Oct/V CV jack IN
- VCO jack out

- Pot for COARSE ? (below Oct/V)
- pot for LIN CV

anything i missed ?


Looks good

The BJT transistors are just AF complementary npn/pnp types, probably not much different to 547/9s or whatever you normally use in synth ccts.
In my experience FETs can be fussier.
Back to top
View user's profile Send private message Visit poster's website
the19thbear



Joined: Apr 19, 2007
Posts: 150
Location: denmark

PostPosted: Mon Apr 23, 2007 4:36 am    Post subject: micro vco
Subject description: micro vco
Reply with quote  Mark this post and the followings unread

any schematics for the microvco? i checked out the website and it was in chinese Shocked i'm a newbie so i need some help--
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1176
Location: australia
Audio files: 4

PostPosted: Mon Apr 23, 2007 8:03 am    Post subject: Re: micro vco
Subject description: micro vco
Reply with quote  Mark this post and the followings unread

the19thbear wrote:
any schematics for the microvco? i checked out the website and it was in chinese


- Japanese!
there doesn't seem to be much synth diy in China ...yet.
the schematic for Masa's microVCO is on this thread - near the start

check out another thread on the microVCO -

http://electro-music.com/forum/topic-16600.html

Also these links take you to Takeda's version of the microVCO

http://www.aleph.co.jp/~takeda/radio/harvest/img/schem/DualTBVCO3a-schem.gif

http://www.aleph.co.jp/~takeda/radio/harvest/pdf/DualTB-pattern.pdf
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [22 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software
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