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dannykorrson 1st October 2019 08:14 PM

yamaha cs50 one voice down
man it hurts typing this out;

I was playing my cs50 recently when I suddenly heard a soft pop and noticed afterwards only 3/4 voices were working. In other words; it cycles through all 4 voices when pressing 1 key repeatedly - and every forth note is silent. for some reason it only affects the saw and square oscillators, when I do the same thing with only the sub oscillator on it plays 4 notes as it should. confoosed

has someone experienced something like this with their cs-xx before?

yesman 5th October 2019 12:21 PM

Hey Danny,
I think you mean the sine wave, which is routed to the VCA, bypassing the filters, the saw and square waves are routed to the filters. On the CS the sub osc is an LFO. If the sine wave is outputting sound, then the osc and vca are working. How about the noise, is that producing sound? If the saw/square & noise are not producing sound then I would expect that the problem is with the filter section. Try opening both filters all the way HP althe way down, LP all the way up - might be the filter env. This may narrow it down to one or the other filter. That's about all I have without being in front of the CS. Hope this helps.

dannykorrson 10th October 2019 05:51 PM


Originally Posted by yesman (Post 14248076)
Hope this helps.

hey yesman, thank you for answering! rockout

you're 100% correct - I meant the sine wave.

I tried the settings you recommended and indeed: noise doesn't produce sound as well on every fourth note: I don't get anything different when opening/closing the LPF as well as the HPF, just silence on every fourth-> that means the issue should be with the filter section. :facepalm:

unfortunately my country only has 1-2 synth guys which are completely booked out - maybe I have to take it to the netherlands cellfone

yesman 11th October 2019 12:06 PM

OK, Danny
Yeah, I'd say the filter section itself or how the signal is being input to the filters.
Good luck

yesman 8th August 2020 01:53 PM

Curious, did you ever sort this?

dannykorrson 8th August 2020 02:58 PM


Originally Posted by yesman (Post 14903643)
Curious, did you ever sort this?

hey there,

thanks for checking in! peachh

unfortunately I didn't get around to get my analytical skills up to a standard of daring to dive inside the cs50. the upside is that I was able to get in touch with one of my countries synth technicians and I dropped it off there 3 weeks ago.

Once I will pick it up I will ask him what the issue was and report to see if your assumption was correct.

dannykorrson 17th August 2020 07:21 PM


Originally Posted by yesman (Post 14903643)
Curious, did you ever sort this?

just got the cs50 back in full working order:
1x IG00153 VCO IC was fried (apparently something went wrong with the heat compensation) and there was something off with one of the envelope generators for another voice that had to be fixed as well.

luckily the synth guy spare parts around and my cs50 is tweeting again in its full 4 voice glory!

now time to put some reverb on that thang and give it a whirl abduction