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Re: M-Board output level- typo in adjustment procedure?

2013-01-21 by David

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
> >
>

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