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problem with diatonic converter

problem with diatonic converter

2009-03-28 by joshdaigleusa

I have built the Diatonic Converter but am having trouble with the Maj/Min input.

I wired up an SPST toggle switch for Maj/Min, with +15VDC wired
through a 100K resistor for Min mode, unconnected (default) for Maj
mode - that should be right, yes? I'm unable to get it to switch to
different modes between Maj & Min - they are exactly the same when I
switch between them while an 8-note run plays up and down the scale.
This is the case whether I use this normalled switch or feed it a
0-5Vp-p pulse wave LFO (and the voltage is definitely getting through to the Maj/Min pins on the CD4053B).

Stranger still, there seems to be some sort of active "field" around
the lower 1/2 of the CD4053B there where the Maj/Min mode is supposed
to be controlled (this isn't happening with any of the other chips and
even not on the top 1/2 of the 4053). If I hold my finger close to the
chip at this spot the control voltage output of the circuit gets
unstable and distorts.

Anyone have any idea what might be going on? I was able to get the board calibrated really well otherwise - works great and is very stable. Could this chip be fried? I'm doubtful because the circuit works otherwise, but I'm not sure what purpose this chip serves in the circuit other than effecting the mode. I'm guessing if it's working otherwise it's probably not as simple as the chip being bad. I'm driving this Diatonic Converter from a Ray Wilson MFOS Quantizer and the quantizer circuit is working perfectly and is also very well calibrated.

Any help very much appreciated.

problem with diatonic converter

2009-03-28 by Paul Newman

I have built the Diatonic Converter but am having trouble with the Maj/Min input.



I wired up an SPST toggle switch for Maj/Min, with +15VDC wired

through a 100K resistor for Min mode, unconnected (default) for Maj

mode - that should be right, yes? I'm unable to get it to switch to

different modes between Maj & Min - they are exactly the same when I

switch between them while an 8-note run plays up and down the scale.

This is the case whether I use this normalled switch or feed it a

0-5Vp-p pulse wave LFO (and the voltage is definitely getting through

to the Maj/Min pins on the CD4053B).



Stranger still, there seems to be some sort of active "field" around

the lower 1/2 of the CD4053B there where the Maj/Min mode is supposed

to be controlled (this isn't happening with any of the other chips and

even not on the top 1/2 of the 4053). If I hold my finger close to the

chip at this spot the control voltage output of the circuit gets

unstable and distorts.

Anyone have any idea what might be going on? I was

able to get the board calibrated really well otherwise - works great

and is very stable. Could this chip be fried? I'm doubtful because the

circuit works otherwise, but I'm not sure what purpose this chip

serves in the circuit other than effecting the mode. I'm guessing if

it's working otherwise it's probably not as simple as the chip being

bad. I'm driving this Diatonic Converter from a Ray Wilson MFOS Quantizer and the quantizer circuit is working perfectly and

is also very well calibrated.

Any help very much appreciated.

_________________________________________________________________
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[Non-text portions of this message have been removed]

Re: problem with diatonic converter

2009-03-28 by Mark

On 3/28/09, joshdaigleusa put forth:
>Stranger still, there seems to be some sort of active "field" around
>the lower 1/2 of the CD4053B there where the Maj/Min mode is supposed
>to be controlled (this isn't happening with any of the other chips and
>even not on the top 1/2 of the 4053). If I hold my finger close to the
>chip at this spot the control voltage output of the circuit gets
>unstable and distorts.

Are you sure you aren't physically touching anything?? That does
sound unusual. Off hand, I'd say you've accidently invented some
sort of theremin :)

I just took a quick glance at the circuit. Since this thing doesn't
appear to have any sort of clock, the first thing I would do is check
the power supply. Make sure all the DC voltages are correct. Check
the output of the voltage reference. Check the outputs of all the
op-amps, and make sure they are what they should be with no input,
0V, -5V, +5V, or whatever. If you have a scope, check for
oscillations around the power pins. Check the PCB for bad solder
joints or excess flux. Make sure that any unused logic pins that
should be tied high or low aren't left floating.

If the chip is socketed, I would try another chip. If it isn't, I'd
try adding bypass caps to the supply pins before unsoldering it, but
that's just me. If you do unsolder it, do not solder in a new chip
-- use a socket. Then if it still doesn't work with another chip,
you can replace the function of the mux by sticking little jumpers of
insulated solid wire. If it still doesn't work, then you know it's
not the 4053.

Re: problem with diatonic converter

2009-03-28 by w1xyzq

Sorry for the off topic question, but how do you drive the converter from the sequencer? It doesn't have analog inputs to get the regular sequencer CV.

thanks!
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, Paul Newman <taviny@...> wrote:
I'm driving this Diatonic Converter from a Ray Wilson MFOS Quantizer and the quantizer circuit is working perfectly and
>
> is also very well calibrated.
>
> Any help very much appreciated.
>
> _________________________________________________________________
> Windows Live™ SkyDrive: Get 25 GB of free online storage.
> http://windowslive.com/online/skydrive?ocid=TXT_TAGLM_WL_skydrive_032009
>
> [Non-text portions of this message have been removed]
>

Re: problem with diatonic converter

2009-03-28 by joshdaigleusa

Thanks for the suggestions. I emailed with Ken and we tracked the problem down. There were 2 issues. First I was wiring the Maj/Min input directly into the Maj/Min pad when it needed to go through one of the input op-amps (this was shown in the example of integrating the Diatonic Converter with the Infinite Melody in the documentation, I just overlooked this at first). The other issue was that the Maj/Min input was left floating when in Maj mode - a tie to ground via a 100K resistor solved this.

Re: problem with diatonic converter

2009-03-29 by w1xyzq

Sorry, I had misread your post earlier. I was reading a different thread about interfacing the converter to the digital chip on the MFOS seq. I read your post too quickly and thought you were talking about the same thing.
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "w1xyzq" <w1xyzq@...> wrote:
>
> Sorry for the off topic question, but how do you drive the converter from the sequencer? It doesn't have analog inputs to get the regular sequencer CV.
>
> thanks!
>
>
> --- In cgs_synth@yahoogroups.com, Paul Newman <taviny@> wrote:
> I'm driving this Diatonic Converter from a Ray Wilson MFOS Quantizer and the quantizer circuit is working perfectly and
> >
> > is also very well calibrated.
> >
> > Any help very much appreciated.
> >
> > _________________________________________________________________
> > Windows Live™ SkyDrive: Get 25 GB of free online storage.
> > http://windowslive.com/online/skydrive?ocid=TXT_TAGLM_WL_skydrive_032009
> >
> > [Non-text portions of this message have been removed]
> >
>

Re: problem with diatonic converter

2009-03-29 by joshdaigleusa

It's a CV Quantizer, not a sequencer (though a sequencer is obviously a very good thing to run through the Quantizer):

http://www.musicfromouterspace.com/analogsynth/VOLTAGEQUANTIZER/VOLTAGEQUANTIZER.php
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "w1xyzq" <w1xyzq@...> wrote:
>
> Sorry for the off topic question, but how do you drive the converter from the sequencer? It doesn't have analog inputs to get the regular sequencer CV.
>
> thanks!
>
>
> --- In cgs_synth@yahoogroups.com, Paul Newman <taviny@> wrote:
> I'm driving this Diatonic Converter from a Ray Wilson MFOS Quantizer and the quantizer circuit is working perfectly and
> >
> > is also very well calibrated.
> >
> > Any help very much appreciated.
> >
> > _________________________________________________________________
> > Windows Live™ SkyDrive: Get 25 GB of free online storage.
> > http://windowslive.com/online/skydrive?ocid=TXT_TAGLM_WL_skydrive_032009
> >
> > [Non-text portions of this message have been removed]
> >
>

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