Dynacord CLS 222 Leslie Simulator clone

29285

Disabled Account
2010-01-17 9:20 pm
Oh yes, cloning the CLS222 is not easy at all.
This is a bunch of complex analogue circuitry about 20 analogue ICs on board.
Some of them, like the bucket brigade delay lines, TDA1022 (Valvo) are out of production for a long time, the VCAs CA3280 are very old, too.
Keep in mind that I designed this beast in the early eightys...:rolleyes:
 

29285

Disabled Account
2010-01-17 9:20 pm
I uploaded the scans of my original schematics.
Sorry, but the quality of these aged paper copy is quite poor.
Hope it helps anyway
 

Attachments

  • cls222.pdf
    303.7 KB · Views: 346
  • cls222-01.pdf
    285.5 KB · Views: 195
  • cls222-02.pdf
    265.3 KB · Views: 167
  • CLS222_EDS.pdf
    347.1 KB · Views: 195

29285

Disabled Account
2010-01-17 9:20 pm
Yes, that is true. I did the whole circuitry and PCB Layout.
My companion W. Dietzmann was the one who checked the sound with his old Hammond A100 and a 760 Leslie Cabinet and he was the one who urged me to do this and that until the sound was satisfying from his perception. The development took me about one year. This happened in the early 80s.
 

mr coffee

Member
2005-09-07 3:49 pm
Thanks Thanks Thanks!!!!!

Thanks so very much voltwide!!!

I'm going to try to re-engineer an analog work-alike using less rare ICs like the LM13700 for the CA3280, TL074, and MN3007 (clocked at double the clock rate).

If there are other folks interested, I'll pass it along - but some other things got ahead on my to-do-next list.

mr coffee
 

DEQ+TheEnd

Member
2005-11-11 1:44 am
Congrats voltwide!
CLS 222 are today considered to be the best sounding analog leslie emulator ever created. I guess the success would be more useful for you if it had happened when the product was still in production. But still, I like to honor you sir.
Do you remember how you started the design? Where there existing chorus effects or similar that inspired your design? Did you work for Dynacord at the time?

mr coffee, yes please. I will love to see an analog leslie effect emerge. I’ve ended up with a Korg G4, but never stopped looking for the CLS 222. But prices this unit now are selling for are far out of my reach.

CA3280 and TDA1022 are still available in small quantity for hobbyist from eBay. But not knowing what exactly are delivered under the label it make sense trying to do this with more “modern” components.
 

29285

Disabled Account
2010-01-17 9:20 pm
This design started as a DIY project. The project grew step by step by comparison to the original Leslie cabinet.

At that time I had some experience with bucket brigade delays, flangers and chorusses. Most of the chorusses at that time worked unsatisfactory, i.e. delay did not sound "round".
I discovered the reason for that was using VCOs for clock modulation.
This yields in voltage-proportional frequency. With bigger modulation depth, the resulting delay variation becomes unssymmetric, simply because delay is proportional to 1/frequency. Thus I decided to build voltage controlled period generators as top frequency oscillators. With that concept the delay modulation yields perfect round sounding flanger/chorus/leslie effect.
Next aspect was loudness modulation. Specially the treble unit produces a angle-dependend acoustic level with a sharp maximum in the direction to the listener. Additionally, there is a smaller maximum due to reflection at the rear wall of the cabinet.
Switching motors works totally asynchrone for treble und bass unit, with a much slower response on the bass unit.

All in all there is not one single secret behind it, but a lot of details I worked out in a period of one year. Circuitry was designed from scratch, there was no relevant information available for me besides the data sheet of the chip. And there were no products on the market at that time that gave me inspiration for the work.

The deal with Dynacord came later, when the first prototype was working completely. Like so often, this happened accidentally. I did some jobs in a commercial dance band, and their leader was a representative of Dynacord....
 

mr coffee

Member
2005-09-07 3:49 pm
Voltwide,
Thanks very much for sharing the engineering aspects that make the CLS-222 sound so good! It makes it easier to understand the schematic and some of the little networks used to warp control voltages, i.e., oh, so that's to make that upper rotor bump in loudness and highs as it rotatestoward the listener. I had to listen to samples again to appreciate the horn reflecting off the rear of the cabinet. Superb job!
mr coffee