Yamaha CS30 OSC SYNC modification?

[radek tymecki]

I've found CS15 modification guide

http://homepage.mac.com/synth_seal/html/ds_cs15mod.html

Found some similarities with cs30 and did LFO mod. Still I'm curious how to make this full 24db mod in CS30? Anyone?

[yusynth]

Hi Radek

I have no CS30 but from the schematics if I wanted to add a 24dB/octave LP function here is what I would do :

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CS30-MOD-24dB-sch.gif
Description:	Schematics modification, the connection from the HP output of VCF1 to VCF2 is broken and a toggle switch is inserted to switch between the LP and HP outputs of VCF1. Obviously if you use a three voices switch you could also add the BP output of VCF1
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CS30-MOD-24dB-PCB.gif
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[radek tymecki]

Hey

Thanx Yves!

[radek tymecki]

There is also little problem with my Yammy, that i figured yesterday.



When i set VCF 2 volume to 0 I can still hear it. I don't know what trimmer should I use to get it proper working

here's service manual

http://manuals.fdiskc.com/flat/Yamaha%20CS-30%20Service%20Manual.zip

[slacker]

I don't think there is a trimmer to adjust. The VCF 2 volume knob in the VCA section is PVR2 on page 11 of the service manual, this is wired as a voltage divider and when turned all the way down should give no sound from VCF2.
I would check all the solder connections to that potentiometer to make sure they are good. If you can also check that when the volume is turned all the way down the wipe (the middle pin) is connected to ground.

[radek tymecki]

ok i'll chceck that. when i turn it to 0 it has same volume as vcf1 set to 10. when i turn vcf2 to 10 it is few times louder

[tiego]

Hi there
New to this forum, thanks to it and the people posting I managed to do the LFO speed hi range adjustment mod and the external sequencer gate mod altogether. I may add that I am no tech at all. I had to check on the net for the polarity of a transistor and had a problem when it came to measure the voltage out of the module to mod!
I am now interested in the Filter yusynth mod, but I was surprised to see the filter specs on the schematics: 6DB slope for HP and LP, 12DB for BP only!

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[tiego]

Over the serial filter 24 or 12 or 18DB/oct mod, I really would like to interface the CS30 to other gear, and I would really be able to externally control the VCFs (and LFO...) ...from synths, KORG MS04 or MSO1 pedal, Frostwave Beam (IR sensor) or Kenton or my Pulse + ( don't know if it should be linear or Log control though...)
Hope this can be accessible for an electro dummy like I.
meaning: I can solder, I have a simple tester , even have a scope somewhere in stock. But not really able to read a schematic...yet
Help would be appreciated nonetheless

The Fader for EG3 release is leaving me, if anybody knows where to find one...
here's a pic of the back of my CS as of today...

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[yusynth]

[tiego]

Thanks for that precision
that LP sounded a bit steep for 6db/oct...

Anyhow, reading your previous post about chaining the 2 Filters thoroughly, assuming i was going to have the BD VCF to the VCF2 thru that 3 position switch,I am wondering: where should I solder the switch pin to on the PCB? ( Dohh)

sonically
Tiego

[radek tymecki]

i've managed to perform vcf mods that Yves showed

[radek tymecki]

I've contacted Eric about his modifications in CS15. He sent me those pics. hope that they'll be helpful to some of You. anyone knows how to transfer SYNC mod to CS30?

[ATGANI]