KORG PS3100/3300 Resonators

fonik

hi all,

anybody built the resonators? i got the k.ishii schematics from 1977 and it's awkward, but i don't understand them!? what's the meaning of the color codes? how is the VC section connected to the resonators?

so has anybody a redrawn version that he is willing to share?

vtl5c3 · Posted: Mon Dec 18, 2006 8:57 am Post subject:

Try this one, though, I'm not sure it's much easier to read than the original:

http://homepage2.nifty.com/rjb/pdf/rjb_diy_synthe_701a_resonator_schem_revA.pdf

fonik · Posted: Tue Dec 19, 2006 7:31 am Post subject:

it took a moment till i get aware of the optos! now it makes sense. Embarassed

i will definitely build those resonators.
one first idea for modification would be the option for independent voltage control of the resonators (ie three switching sockets, internally connected: as soon as you plug in more patchcords, the resonators will be modulated independently).
and then i will omit the lfo (have some in my modular already).

anyway, thanks for the kind reply.

mono-poly · Posted: Tue Dec 19, 2006 12:16 pm Post subject:

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

I am getting this one hopefully before christmas.

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

I would recommend using these schematics instead of the original:

http://homepage2.nifty.com/rjb/pdf/rjb_diy_synthe_701a_resonator_schem_revA.pdf

the only thing you have to modify is substitute the LDR in this schematic with a vtlc53/2

cheers,
michel

fonik · Posted: Tue Dec 19, 2006 1:43 pm Post subject:

thanks for taking care.

got the link yesterday and guess what? started the redraw of the schematic today substituting the LDRs with... bingo: VTL3C2s Very Happy

BTW it's a great community here... got some kind PMs in this case again.

Scott Stites · Posted: Tue Dec 19, 2006 2:08 pm Post subject:

Hey Matthias,

I've breadboarded the circuit. Still have it on breadboard, sans the Vactrols (they were stolen in my Vactrol matching frenzy on the MultiPhase project).

Here's an excerpt from my Birth of a Synth page, 09 May 2004:

fonik · Posted: Wed Dec 20, 2006 12:02 am Post subject:

fonik · Posted: Thu Jan 11, 2007 11:08 am Post subject: Subject description: what parts

vtl5c3 · Posted: Thu Jan 11, 2007 11:49 am Post subject:

General Purpose transistors should work fine. The MOTM version uses BC550Cs and 560Cs. No diodes in their version, but I bet 4148s would be fine.

fonik · Posted: Thu Jan 11, 2007 3:06 pm Post subject:

what's good for MOTM should be enough for me Wink

v-un-v · Posted: Thu Jan 11, 2007 3:18 pm Post subject:

andrewF · Posted: Thu Jan 11, 2007 3:31 pm Post subject: Subject description: what parts

>now i'm really starting to build this thing! the schematics ask for >"epitaxial type" transistors 2SC1815 and 2SA1015. Would general >purpose transistors do? (and what means this "epitaxial").

I have built dozens of CGS and Electronotes circuits using 2SC1815 and 2SA1015, as I bought 1000s of them in Japan, they can be sub'd with any generic transistor.
The pinout is different - ecb, otherwise much the same as say BC547/9s

It is worth checking out the full page for this project. RJB is a very clever guy and his build quality is among the best.
scroll down to see his home screenprinted panels
http://homepage2.nifty.com/rjb/diy_synthe12.htm

Andrew

Scott Stites · Posted: Thu Jan 11, 2007 6:57 pm Post subject:

RJB da man, for shore!

FWIW, I used 2N3904 and 2N3906.

Cheers,
Scott

fonik · Posted: Thu Jan 11, 2007 11:39 pm Post subject:

thanks a lot for the replies, guys!

i already made my own PCB and will start to populate it soon (whatever "soon" means this time)...

The Alison Project · Posted: Fri Jan 12, 2007 9:01 am Post subject:

Let us know how it turns out.

After reading the links Scott provided I ended up buying a MAM RS3 Resonator, but I would always be interested in building my own, it is one amazing filter.

Chris

fonik · Posted: Fri Jan 12, 2007 4:03 pm Post subject:

fonik · Posted: Thu Jan 25, 2007 10:49 am Post subject:

hey, i'm still working on that resonators! i made a pcb and now i recognize, that i forgot(!) some resistors Embarassed

i wonder what these resistors are for?

referring to RJBs mod schematic i forgot the 10k resistors between the transistors and the 470R resistors between the PNPs and the LEDs of the vactrol.
for now i get a dramatic voltage drop on the negative rail as soon as i open the trimmer pots for the CV in's. maybe the omitted resistors are the reason?
(i replaced the SC1815/SA1015 by BC550/BC560 taking care of the different pinout for certain)

any comment highly appreciated! i looking for advice and teaching...

andrewF · Posted: Thu Jan 25, 2007 4:46 pm Post subject:

Maybe the 10Ks are not a big drama, giving more of an on/off effect with little control in between.

the 470s are for the leds in the vactrols, you can easily pop an led if there is no current limiting resistor.

i built this one on a vero, haven't tested it yet.....no doubt there will be something missing.

fonik · Posted: Thu Jan 25, 2007 11:34 pm Post subject:

fonik · Posted: Fri Jan 26, 2007 10:08 am Post subject:

... and thats what actually happened, i think.
i incorporated the missing resistors and there's no filtering! i fired the vactrols, i guess! arrgh!

there's no voltage change at the vactrols LED+, no matter what control voltages applied...

Scott Stites · Posted: Fri Jan 26, 2007 11:39 am Post subject:

Wuh-oh. Been there, done that. When I was matching Vactrols for my phaser, I toasted two in the wink of any eye by misplacing a wire and running the current unimpeded through the LED's. Fortunately, I only had two in series. Still broke my heart - I put the corpses away for later dissection and possible rejuvination with new LEDs.

Do you have any backups? What device were you using?

The 470R value in the design gives me the willies - I work for a communications/avionics test solutions company - a company sort of the counterpart for what I'm sure the company State Machine works for (he may even use our equipment). Anyway, the SINAD meter in one of our old boxes used an optocoupler in the null circuit - seems I would always have to change the thing out, and I'm convinced it was because it was just pulling too much current through the LED - over time it would just play out. So, I've always tried to stick well within the LED current spec. Not saying this design doesn't (being RJB, I certainly wouldn't second guess it), it's just that, when designing, I loathe going below 1K if 15V has even a chance of hitting that anode.

The resonator I'm working on now doesn't use Vactrols. Breadboarded it last Saturday/Sunday, and it's been blowing my mind all week. Not really my design, just somebody else's X3. I call it the 'Raysonator' if that's any kind of hint Very Happy

It's not a first - I believe the Technosaurus triple res is without Vactrol as well.

Anyway, as such, there are already PCBs available for most of it. I've fallen in love with it....

Web Page to follow.

Cheers,
Scott

vtl5c3 · Posted: Fri Jan 26, 2007 2:44 pm Post subject:

Scott Stites · Posted: Fri Jan 26, 2007 3:51 pm Post subject:

fonik · Posted: Fri Jan 26, 2007 4:01 pm Post subject: