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Complete VCF Alignment

Complete VCF Alignment

2014-01-17 by <joachim.milson@...>

Did someone achieve a complete VCF alignment?
I'm asking this because while following the steps on page 11 of the CS80's adjustment procedure manual, I came across voltages that are different from those on my unit, and even unreachable with the variable resistors.
Using VR7 and VR9 to shift the cutoff frequencies of both filters to get the maximum amplitude is OK. The problem occurs while trying to use VR8 and VR10 to set the resonance. The amplitude I can get is 2.8Vp-p, but certainly not 4.3Vp-p with HPF and 1Vp-p instead of 2.2Vp-p with LPF. Did someone notice analogous variations?

Re: Complete VCF Alignment

2015-12-25 by joachim.milson@...

Hello,
I recently decided to calibrate the filters of the master boards.
Since the values on page 11 of the service manual are wrong, I made a few trials and finally chose the settings visible here.
What values are you using when you do a complete VCF alignment?
Perhaps one of you owns a copy of the service manual where the right values were added by a technician in the past?
Thanks for your answers and merry Christmas to all!

Re: Complete VCF Alignment

2016-01-24 by yahoogroups@...

I wonder about this too. I have been in touch with JM while calibrating my CS-80 and after a few days of experimentation and discussion we have different findings.

I had trouble on two voice boards to go up to 8.4Vpp for HPF resonance, so I decided to take the value from the CS-60 manual and go for the 7.6Vpp as instructed there. Not sure what the right value for a CS-80 is or where it starts to sound wrong.

Also instruction for the 2.2Vpp for LPF cutoff does not seem right. If I want to go for 2.2Vpp I have to dial the trimpot almost full to the end. The original value gave me a reading of 1.4-1.6Vpp, so I did the same as JM and used 1.6Vpp.

I wonder about the other guys who work on CS-80s how you handle this part or what your findings are?

Re: OT: Supplemental Booklets etc.

2016-03-27 by Daniel Forró

Some time ago I have scanned DX7 II Supplemental booklets contributed by some members of YamahaDX yahoo group, our college Rawl Gelinas processed scans and now all of them are for public use officially (together with AfterTouch magazine we two have scanned).

Still some booklets are missing:

Quick Reference Guide
Modifying Preset Voices
Understanding Fractional Scalings
Programming Fractional Scalings
Memory Management
Advanced Midi Applications

Yamaha published in the end of 80ies also "QX3 Operations & Applications Supplemental Booklet", and some guidebooks for V50 synthesizer:

Performance Voicing Guidebook
Rhythm Programming Guidebook
Sequencer Guidebook
(+ Demo Data Disk)

If by chance somebody here has anything from these, and is willing to sell, contribute or just lend for scanning (I will pay for shipment in all cases), everybody can later get it as PDF - same case as the previous material we have scanned and published.

Thanks for any info or contribution.

Daniel Forro