Yamaha CS80

Hi Kent,

thanks for the explenation. 64 vca-ic's, that's a lot of rare ic's. 
I thought you would generate the extra lfo's digitally ;-)
Personally, I don't need the seperate lfo-mod. However, I find it 
difficult to program nice string-sounds on the CS80. I don't even 
come close to the strings of an prophet, jupiter or OB-8 etc. 
There's allways too much or too little PWM. It just sounds to much 
modulated and not as a rich stringsound. I don't know why, is it the 
filter ? I guess (!) that having the PWM lfo phase-shifted for each 
voice seperatly could give nice results, maybe a simple circuit 
would do the trick ? Why would we need to have the PWM on all voices 
phase-synced, I don't anyway ?

Can you explain the unison-mod a little ? Can you choose 2-,4- and 8-
voice ? Can you play a 2-unison 4-voice polyphonic etc etc ?

We would love to know what kind of mods can be done by you, maybe 
some of us are interested in your modifications and have them let 
done by you (as soon as you have your garden cleaned up).

Do you have the CS80's re-tolexed by yourself or is someone else 
specialised in this ? I think it's a hell of a job, isn't it ?
I suspect you have a crane to lift the complete circuits out of the 
case in one piece to give you room to retolex ;-)

Please go on restoring and fixing these great machines !
Erik


--- In yamahacs80@yahoogroups.com, "kent spong" <kent_spong@...> 
wrote:
>
> Hi Erik,
> 
> Yes that's right. The 16 IG00150 VCO's are for the VCO, VCF and 
VCA of the 
> LFO section and are also controlled by the after touch too. The 
only down 
> side to this mod is the 64 IG00151 VCA IC's it uses. The whole 
thing is 
> switched in and out on the LFO EXT point on the waveshape slider 
and also 
> swiches out on the EXT Modulation socket on the back. So there is 
no change 
> to the front panel of the 80 at all. However,  I am working on a 
totally 
> faithfull replacment front panel for the 80 to restore one's that 
have seen 
> to much damage over the years. I want to keep these fantastic 
machines going 
> for as long as I can.
> 
> 
>