Yamaha CS80

Dear CS-80 friends,

while tuning my CS-80 according to Yamaha´s adjustment procedure I
wonder about the VCA #4 gain value (step 4 on page 15). This VCA sets
the individual output level of each Voiceboard.

According to the manual it should be adjusted with VR14 to 80mV pp.

This is ridicoulus low and my CS-80 came with a much higher level on
each card, so I am not sure if the value in the manual is correct.

As I understand, increasing the output level of each card would result
into a better S/N ratio but could overload the following output stages
(PRA, Effect section etc.) if set too high, especially when playing 8
voices together.

Has anybody figured out already if those 80mV are accurate or if it is
recommended to adjust to a higher value here? To my feeling something
between 200 and 400mV should be more useful,

Thanks, Gregor

Hi Gregor,

I would imagine that most people would not go too mad on this value
really. I would worry more about initial vca trims on Trig 1 and 2
boards and then use vr14 on the m boards as a final tweak in a
calibration process.






--- In yamahacs80@yahoogroups.com, "willgregori" <will.gregory@...>
wrote:

>
> Dear CS-80 friends,
>
> while tuning my CS-80 according to Yamaha´s adjustment procedure I
> wonder about the VCA #4 gain value (step 4 on page 15). This VCA

sets

> the individual output level of each Voiceboard.
>
> According to the manual it should be adjusted with VR14 to 80mV pp.
>
> This is ridicoulus low and my CS-80 came with a much higher level

on

> each card, so I am not sure if the value in the manual is correct.
>
> As I understand, increasing the output level of each card would

result

> into a better S/N ratio but could overload the following output

stages

> (PRA, Effect section etc.) if set too high, especially when playing

8

> voices together.
>
> Has anybody figured out already if those 80mV are accurate or if it

is

> recommended to adjust to a higher value here? To my feeling

something

> between 200 and 400mV should be more useful,
>
> Thanks, Gregor
>

Hi Kent,

I just stumbled across this because I do not get a proper sine wave on the IC5 pin 13 Tremolo/Chorus section with the M-boards providing a plain sine wave and output level 80mV only. If I increase this to 200mV then it looks good. However, I worry about overloading the effect section then.

The initial VCA trims on TRG boards is for setting up the touch response? I have still 10 pages to go on the complete tuning procedure...

G.



-------- Original-Nachricht --------

> Datum: Sun, 14 Dec 2008 12:36:42 -0000
> Von: "kent_spong" <kent_spong@...>
> An: yamahacs80@yahoogroups.com
> Betreff: [yamahacs80] Re: M-Board output level- typo in adjustment procedure?

> Hi Gregor,
>
> I would imagine that most people would not go too mad on this value
> really. I would worry more about initial vca trims on Trig 1 and 2
> boards and then use vr14 on the m boards as a final tweak in a
> calibration process.
>
>
>
>
>
>
> --- In yamahacs80@yahoogroups.com, "willgregori" <will.gregory@...>
> wrote:
> >
> > Dear CS-80 friends,
> >
> > while tuning my CS-80 according to Yamaha´s adjustment procedure I
> > wonder about the VCA #4 gain value (step 4 on page 15). This VCA
> sets
> > the individual output level of each Voiceboard.
> >
> > According to the manual it should be adjusted with VR14 to 80mV pp.
> >
> > This is ridicoulus low and my CS-80 came with a much higher level
> on
> > each card, so I am not sure if the value in the manual is correct.
> >
> > As I understand, increasing the output level of each card would
> result
> > into a better S/N ratio but could overload the following output
> stages
> > (PRA, Effect section etc.) if set too high, especially when playing
> 8
> > voices together.
> >
> > Has anybody figured out already if those 80mV are accurate or if it
> is
> > recommended to adjust to a higher value here? To my feeling
> something
> > between 200 and 400mV should be more useful,
> >
> > Thanks, Gregor
> >
>
>

Hi all & Happy New Year!

I just did the whole VCA adjustment a couple of says ago on a CS80 and also question the vr14 80mv.
First, it doesn't say to desolder the M-Card output wire until the next step, but you really need to do it for this step or you've got the noise from 8 M-Cards mixed together.
Next, at 80mv, the sine wave was about 1/4 noise. It took quite a bit of DSP in my head to figure out where the peaks of the sine wave would be :)

https://www.dropbox.com/s/o1un5uzhqobbzjh/2013-01-19%2017.20.13.jpg

I did get all 16 cards matched to this but, as Gregor originally wrote, this means you have to turn up the output level a lot more which is really bad for the already-noisy chorus unit.

Any recommendations on this?

David

p.s. - I really should read my own forum :)

--- In yamahacs80@yahoogroups.com, "kent_spong" wrote:
>
> Hi Gregor,
>
> I would imagine that most people would not go too mad on this value
> really. I would worry more about initial vca trims on Trig 1 and 2
> boards and then use vr14 on the m boards as a final tweak in a
> calibration process.
>
> --- In yamahacs80@yahoogroups.com, "willgregori"
> wrote:
> >
> > Dear CS-80 friends,
> >
> > while tuning my CS-80 according to Yamaha´s adjustment procedure I
> > wonder about the VCA #4 gain value (step 4 on page 15). This VCA
> sets
> > the individual output level of each Voiceboard.
> >
> > According to the manual it should be adjusted with VR14 to 80mV pp.
> >
> > This is ridicoulus low and my CS-80 came with a much higher level
> on
> > each card, so I am not sure if the value in the manual is correct.
> >
> > As I understand, increasing the output level of each card would
> result
> > into a better S/N ratio but could overload the following output
> stages
> > (PRA, Effect section etc.) if set too high, especially when playing
> 8
> > voices together.
> >
> > Has anybody figured out already if those 80mV are accurate or if it
> is
> > recommended to adjust to a higher value here? To my feeling
> something
> > between 200 and 400mV should be more useful,
> >
> > Thanks, Gregor
> >
>