Good work! My tuning is pretty close, but I have not touched the antilog trimpots, so
I am looking forward to getting this really nailed so that I can get it even better, as you did. One thing I don't understand is how the 4051's are being used to change the behavior of the circuit. And what is the fcn of the opto-coupler? Any thoughts?
Bob
I am looking forward to getting this really nailed so that I can get it even better, as you did. One thing I don't understand is how the 4051's are being used to change the behavior of the circuit. And what is the fcn of the opto-coupler? Any thoughts?
Bob
From: Malte Rogacki <gacki@gacki.sax.de>
To: PolySix@yahoogroups.com
Sent: Sunday, March 2, 2014 9:05 AM
Subject: Re: [PolySix] RE: Polysix tuning difficulties.
To: PolySix@yahoogroups.com
Sent: Sunday, March 2, 2014 9:05 AM
Subject: Re: [PolySix] RE: Polysix tuning difficulties.
And finally:
I've tuned the Polysix (so far just preliminary). There still is some small
room for improvement but except for the lowest 16' octave I have a pitch
deviation better than the one shown in the service manual. Some notes have
a 1 to 2 cent deviation but most are spot on. The lowest notes in the
lowest octave have currently a deviation of about 7 cent.
I had to use VR15 a lot though which means that probably the basic offset
was not so good. The whole antilog circuit calibration could probably be
shifted a bit upwards and then compensated for again with VR15. This could
possibly bring VR2 away from its end position.
I've tuned the Polysix (so far just preliminary). There still is some small
room for improvement but except for the lowest 16' octave I have a pitch
deviation better than the one shown in the service manual. Some notes have
a 1 to 2 cent deviation but most are spot on. The lowest notes in the
lowest octave have currently a deviation of about 7 cent.
I had to use VR15 a lot though which means that probably the basic offset
was not so good. The whole antilog circuit calibration could probably be
shifted a bit upwards and then compensated for again with VR15. This could
possibly bring VR2 away from its end position.