Living VCOs

TekniK · Joined: Aug 10, 2008 Posts: 1059

Yes i know u need 3 tempcos,but my Q is that i wander if its the known 1v/oct exponential generator circuit design where the 3046 self is acting as a temp compensator and warms up where u just added an extrnal tempco on it?

Spratty · Joined: Oct 08, 2007 Posts: 43 Location: Australia

Hi JH,

I really enjoyed the demo of these oscillators. You really have quite a knack for putting together toys that appeal Smile

I could quite happily see myself building this one and spending hours messing with the VCO's.

---------------------------------

From looking at the BOM for this project a lot of the parts are very common. What I do however ponder about as an Aussie is sourcing those 10 turn pots and verniers. Quotes I have gotten so far for these things have been stupidly expensive, unless I want to buy a lot of the things (and trust me, I wouldn't know what to do with 20+ of each of these). Does anyone know of a place that will sell these items for a reasonable price for small quantities (USD?) without a huge shipping fee or high minimum order quantity?

Spratty Wink

2thick4uni · Joined: Feb 20, 2009 Posts: 113 Location: UK

jhaible · Posted: Thu Apr 09, 2009 8:37 am Post subject:

jhaible · Posted: Thu Apr 09, 2009 8:39 am Post subject:

/mr · Posted: Thu Apr 09, 2009 9:15 am Post subject:

jhaible · Posted: Thu Apr 09, 2009 10:34 am Post subject:

synthetic · Joined: Jun 02, 2007 Posts: 76 Location: Glendale, CA

Can you talk a little about the "Living" section of the VCOs yet? Your linear detune circuit?

2thick4uni · Joined: Feb 20, 2009 Posts: 113 Location: UK

Is it possible to add sync to two of the VCO's? I understand that a lot of design effort has gone into getting it so the VCO's free run when very close in frequency, but if I could add a sync switch too it would be very useful.

I know that schematic hasn't been posted yet, just need a yes or no at this stage as I'm not sure if the VCO core follows usual integrator / comparator sawtooth design............

jhaible · Posted: Thu Apr 09, 2009 11:31 pm Post subject:

jhaible · Posted: Fri Apr 10, 2009 11:37 am Post subject:

delayed · Joined: Jun 24, 2008 Posts: 130 Location: TN

where do you get the Tempco's ? Perhaps a part number or link? I am in the US and the Farnell number says they do not stock them. Is there a company that ships these within the US? Also perhaps a place to get the 3 10 turn pots?

Thanks,

vtl5c3 · Posted: Fri Apr 10, 2009 1:51 pm Post subject:

Check with Bridechamber:

http://www.bridechamber.com/bridechamber.com/Hard%202%20Find%20ICs.html

numbertalk · Posted: Fri Apr 10, 2009 5:17 pm Post subject:

I second Bridechamber for the Tempcos.

This is what I got for the 10-turn pots:

http://www.mouser.com/Search/ProductDetail.aspx?R=3590S-2-103Lvirtualkey65210000virtualkey652-3590S-2-103L

Hopefully that one will work!

dingebre · Posted: Fri Apr 10, 2009 7:47 pm Post subject:

Bridechamber, Magic Smoke Electronics, and Precision Resistor all sell through hole tempcos of different values.

Tobias is selling two kinds of kits, if you didn't see his post. One with all PCB parts and the 10 turn pots, dials, and panel trimmers, one with just the PCB parts. I just bought the parts kit from Tobias (well, two actually, thank Tobias).

I'm doing a FracRack version so I wanted to choose my own -small- dials and pots.

I bought these dials:
https://www.alliedelec.com/Search/ProductDetail.aspx?SKU=6640008&MPN=412&R=6640008&SEARCH=6640008&DESC=412

and these pots:
http://www.mouser.com/Search/ProductDetail.aspx?R=534-1-1-103virtualkey59400000virtualkey594-53411103

I bought these holders for panel mounting of 3/4 inch PCB mount multi-turn trim pots (I needed them for other projects, too.):
http://www.mouser.com/Search/ProductDetail.aspx?R=006-1-0virtualkey59400000virtualkey594-610

I'll put them on a small piece of pad-per-hole vero board and hook up to that.

Got the pots and knobs today and they look/work great.

Can't wait for all the stuff.

jhaible · Posted: Sat Apr 11, 2009 1:46 am Post subject:

jhaible · Posted: Sat Apr 11, 2009 5:11 am Post subject:

I've just put some wiring options up on my web site:
http://www.jhaible.de/living_vcos/jh_living_vcos.html

These are just some ideas - it's up to you what you really want to implement, and what to omit.

JH.

jhaible · Posted: Sat Apr 11, 2009 2:13 pm Post subject:

... and here is a demo of a *single* VCO with PWM-overmodulation in CS-80 style:

http://www.jhaible.de/living_vcos/living_vcos_single_vco_pwm.mp3

(One VCO thru wide open filter + VCA + reverb)

JH.

synthetic · Joined: Jun 02, 2007 Posts: 76 Location: Glendale, CA

Bridechamber may be doing a kit as well.

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

I was planning on passing this project by but decided to put my order in for a PCB. I have only 5U of space remaining in my modular so I was going to try and hold off for a while - it can't be done!

I played around with a 5U module design but just don't want to use that much space. I simplified the design a bit to fit in a 4U module with 6 knobs per VCO with a horizontal organization. I shrunk this down to a 3U by eliminating the VCO out mix knobs. I ended up changing the 3U design to a vertical format that I like the best. All the designs use the smaller knobs as do my other JH modules.

The various concept panels are on a new page at
http://modularsynthesis.com/jhaible/lvcos/jhlvcos.htm

Here is the 3U design that I like the best. - Dave

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

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

TekniK · Joined: Aug 10, 2008 Posts: 1059

ach_gott · Joined: Sep 09, 2008 Posts: 79 Location: Chicago

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

How critical is the exact value of the 2n7 polystyrene cap? I only have a single 2n7 in stock but loads of 3n3. If it is critical, does it pay to order 1% polystyrene?

jhaible · Posted: Wed Apr 15, 2009 1:18 pm Post subject: