Driver to drive?

Jim Thompson · Oct 28, 2011

On Thu, 27 Oct 2011 20:11:39 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:4EAA000F.6040106@electrooptical.net:

Try 10M from the PD2 output to ground.

Thanks. I got to stop now. Late, and my eyes actually hurt...

Jim Thompson · Oct 28, 2011

On Thu, 27 Oct 2011 18:09:36 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Thu, 27 Oct 2011 19:58:59 -0500, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:s3uja71sjd1kluivcb5u9krh05l66cli6b@4ax.com:

What is it you're trying to do? Sub-bass? Chasing lights? What? I
did all that s!@# ~40 years ago ;-)

Whistle to MIDI convertor. Seriously. I actually got fairly good at
whistling. I can play a bass guitar fairly well now, and keyboard (with right
hand only, poor co-ordination for both), but whistling will allow a very good
solo line, and combining that with keyborad via MIDI might give a lead
guitarist a hell of a run for their money! A prospect of an instrument that
fine has to be worth some effort to acheive. Dieter Doupfer is planning
somethign similar using all digital derivations, but his project is forver on
the back burner. As I'll settle for something less than ideal for many
input signals, and already have some good work done, I can hopefulyl get by.
I still rely on one of his inventions, which allows a control voltage to
fluently scale across several octaves of MIDI to make a monophonic synth play
a clean sweep across the entire key range. I had to modify the gadget
slightly to do this, but he solves the biggest problem for me, all I have to
do is give it a voltage it can use.

No matter how many times people have tried to make this basic notion a
reality, it still doesn't exist commercially. Since Bob Moog's log amp, not
all that much has changed. At least in the LOG112 I can get that bit ready
made with more accuracy and stability than I'll ever need. The weak link
seems to be the VCO in the PLL, but maybe it's good enough if I can get
0.25%. A brain can usually make itself part of a live player's feedback loop
somehow. Violinists have always seemed to manage.

So? You're trying to convert your "whistling" to a tracking tone?
Amplitude matching as well as frequency?

...Jim Thompson

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:340ka7hhbqo40j4ni43blqa3mh3baupq2v@4ax.com:

So? You're trying to convert your "whistling" to a tracking tone?
Amplitude matching as well as frequency?

Yes, but envelope followers are the least of the difficulty. Catching subtle
nonlinear pitch bends and vibrato are far more important. Playing those by
hand can take years of practise, but I can whistle them immediately and
effectively, so I might as well try to catch that and use it.

The usual instrument people think of for the kind of expression I'm after is
a Theremin, or an Ondes Martinot. I can't afford the first, never mind the
second, and learning them wouldn't be easy either, and neither use MIDI. A
Doepfer R2M ribbon controller is a cheaper way, but I can't be doing with the
ribbon bit, it's the control box that does Great Things, so long as I can get
it a voltage to use.

George Herold · Oct 28, 2011

On Oct 27, 2:00 pm, Lostgallifreyan <no-...@nowhere.net> wrote:

Phil Hobbs <pcdhSpamMeSensel...@electrooptical.net> wrote innews:rZudndP6woK-CDTTnZ2dnUVZ_v-dnZ2d@supernews.com:

It depends on the circuit constants. You want the total charge flowing
through the resistor per cycle to equal that contributed by some safe
number T nanoseconds' worth of the phase detector pulling HIGH or LOW.
T is something like 10 for HCMOS at 5V, maybe 50-200 for metal gate,
depending on the supply voltage. A current source is probably better,
but that's getting a bit fancy.

If you have a spectrum analyzer, look at the output with and without the
resistor--maybe use a pot for testing purposes. The change in the
jitter sidebands is pretty dramatic when you pull just outside the
deadband.

Please can you give a hobbyists guide type starting point? I.E. starting
resistor value to try, and what pin number on a 4046, to connect to ground?
From my perspective, trying to understand the circuit behaviour without that
info, or to depend on using a spectrum analyser I haven't got, is entirely
putting cart before horse.

Do you have a digital 'scope? They have a so-so spectrum analyzer.
As far as phase locked loops, I don't know the 4046. But there are a
few different approaches. The AoE is as good a place to start as
any.
I'm very interested in the use of the 4046 as VCO. At the moment I'm
using one to drive a stepped sine thingie. I've been starring at the
spec sheet curves wondering if there's a sweet spot somewhere in R/C
space. At the moment I've got R=20k and C=470pF.

George H.

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:co0ka7pvdgck5a2uml9l9rqil90c9q4p7e@4ax.com:

Amusing problem. Can you record your whistling in some
piece-wise-linear format?

I try not to. I hate the sound, and of my voice on any recording. It's the
pitch control and dynamic control I like. Those work. But the sooner I
convert them to sounds I actually LIKE, the better.

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:gm0ka7tk0c1hdqkchmu4m12g36ka1adv7p@4ax.com:

Thanks. I got to stop now. Late, and my eyes actually hurt...

Try not worrying about it.

I think rest works better... Ň^O

Jim Thompson · Oct 28, 2011

On Thu, 27 Oct 2011 20:20:08 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:340ka7hhbqo40j4ni43blqa3mh3baupq2v@4ax.com:

So? You're trying to convert your "whistling" to a tracking tone?
Amplitude matching as well as frequency?

Yes, but envelope followers are the least of the difficulty. Catching subtle
nonlinear pitch bends and vibrato are far more important. Playing those by
hand can take years of practise, but I can whistle them immediately and
effectively, so I might as well try to catch that and use it.

The usual instrument people think of for the kind of expression I'm after is
a Theremin, or an Ondes Martinot. I can't afford the first, never mind the
second, and learning them wouldn't be easy either, and neither use MIDI. A
Doepfer R2M ribbon controller is a cheaper way, but I can't be doing with the
ribbon bit, it's the control box that does Great Things, so long as I can get
it a voltage to use.

Jim Thompson · Oct 28, 2011

On Thu, 27 Oct 2011 20:23:17 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:gm0ka7tk0c1hdqkchmu4m12g36ka1adv7p@4ax.com:

Thanks. I got to stop now. Late, and my eyes actually hurt...

Try not worrying about it.

I think rest works better... Ň^O

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:r32ka71kmrf3h7eicebl2m7fkd2qp64a12@4ax.com:

An old man's (me) advice... you're making the problem too difficult...
study my boom box posts.

Trust me, there are well known names in the electronic music project field
like RA Penfold and Craig Anderton who came up with designs that were far
more complex than mine. As mine uses an op-amp as Schmitt trigger to allow
PC1 instead of PC2 in the PLL I get a BIG leap in performance accuracy and
sensitivity over the usual ways. So long as the PLL's VCO is linear enough
I get a CV I can use free of charge, the only other thing I need is the log
converter, which I also have now.

The only method I'm aware of that is simpler than mine, is the one in a Korg
MS10 'modular' synthesizer, and that one's horrible.

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:172ka7p0k6p4fq8dlnl8ioou6lkk8gg280@4ax.com:

On Thu, 27 Oct 2011 20:23:17 -0500, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:gm0ka7tk0c1hdqkchmu4m12g36ka1adv7p@4ax.com:

Thanks. I got to stop now. Late, and my eyes actually hurt...

Try not worrying about it.

I think rest works better... Ň^O

I make it a point to completely crash every night... shut down the
mind and rest it... watch a movie... eat a steak... drink some wine...
drink some more wine... ;-)

...Jim Thompson

I watched Bond earlier, but too much caffiene this morning took its toll...

Phil Hobbs · Oct 28, 2011

On 10/27/2011 09:53 PM, Lostgallifreyan wrote:

Jim Thompson<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:r32ka71kmrf3h7eicebl2m7fkd2qp64a12@4ax.com:

An old man's (me) advice... you're making the problem too difficult...
study my boom box posts.

Trust me, there are well known names in the electronic music project field
like RA Penfold and Craig Anderton who came up with designs that were far
more complex than mine. As mine uses an op-amp as Schmitt trigger to allow
PC1 instead of PC2 in the PLL I get a BIG leap in performance accuracy and
sensitivity over the usual ways. So long as the PLL's VCO is linear enough
I get a CV I can use free of charge, the only other thing I need is the log
converter, which I also have now.

The only method I'm aware of that is simpler than mine, is the one in a Korg
MS10 'modular' synthesizer, and that one's horrible.

The dead zone is only an issue with PD2. PD1 is nonlinear as well, but
only at the very edges where you're about to lose lock anyway.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Jim Thompson · Oct 28, 2011

On Thu, 27 Oct 2011 20:53:45 -0500, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:r32ka71kmrf3h7eicebl2m7fkd2qp64a12@4ax.com:

An old man's (me) advice... you're making the problem too difficult...
study my boom box posts.

Trust me, there are well known names in the electronic music project field
like RA Penfold and Craig Anderton who came up with designs that were far
more complex than mine. As mine uses an op-amp as Schmitt trigger to allow
PC1 instead of PC2 in the PLL I get a BIG leap in performance accuracy and
sensitivity over the usual ways. So long as the PLL's VCO is linear enough
I get a CV I can use free of charge, the only other thing I need is the log
converter, which I also have now.

The only method I'm aware of that is simpler than mine, is the one in a Korg
MS10 'modular' synthesizer, and that one's horrible.

Lostgallifreyan · Oct 28, 2011

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:vv3ka7todet6nuff7issfd24be4ck0spnm@4ax.com:

An old man's (me) advice... you're making the problem too difficult...
study my boom box posts.

Trust me, there are well known names in the electronic music project
field like RA Penfold and Craig Anderton who came up with designs that
were far more complex than mine. As mine uses an op-amp as Schmitt
trigger to allow PC1 instead of PC2 in the PLL I get a BIG leap in
performance accuracy and sensitivity over the usual ways. So long as
the PLL's VCO is linear enough I get a CV I can use free of charge, the
only other thing I need is the log converter, which I also have now.

The only method I'm aware of that is simpler than mine, is the one in a
Korg MS10 'modular' synthesizer, and that one's horrible.

Who needs a PLL? I'll now go silent ;-)

Ok,

Well, I'll say a bit more... I need one. First, I wanted the
waveforms, same as those guys on that web page did, for an analog oscillator.
Second, I wanted it for the clean square after my Schmitt trigger, for a
freq-to-volt converter before I learned than the response that way was too
slow. Then I realised I had a voltage already from the PLL, if the VCO was
linear enough, and I could do divisions for frequency shifts, all sorts of
fun stuff, just by staying with it, so I stayed. Given how cheap they are,
it's a damn good idea to do that anyway. It's either that or learn to do it
all digitally. Dieter Doepfer is far better at that than I'll ever be, and he
hasn't solved it that way either.

I found the boom-box PDF via a bit of Googling, but I need something I can't
do with op-amps and a flip-flop. They might get me a nice square wave in a
deeper octave, but suppose I want a higher one? They don't get me a control
voltage without frequency to voltage conversion, and that';s even slower in
bass response, so I'd have to shift upwards, putting the flipflop in a PLL
loop. And the PLL also gives me the CV ( I swear I said that before. >

and
it also gives me some nice raw analog waves like saw and triangle with a bit
of coercion. In short, it's way too good an idea to ignore. There are whole
synthesizers that cost hundreds that aren't this much fun.

Lostgallifreyan · Oct 28, 2011

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:4EAA0F1B.7070909@electrooptical.net:

The dead zone is only an issue with PD2. PD1 is nonlinear as well, but
only at the very edges where you're about to lose lock anyway.

Indeed.

Is one reason I like it. I was fairly chuffed when I realised my
Schmitt trigger cleanup method let me use it instead of PC2 which most people
(even those in the synthesiser business, earning money) would use. I started
doing it that way too, and the results were as dodgy as the Korg MS10 and
most other things I'd heard. With Schmitt and PC1 I could whistle faintly
across a room, and the thing would be tracking pitch cleanly at amplitudes so
low I could barely discern it in my own whistled tone. This is great because
it means I can pick out a clean pitch long before I decide what any
subsequent process will do with it prior to output. When Dieter Doepfer told
me about his digital method, he surprised me by telling me that he didn't
have it start trying to track pitch till a threshold on amplitude was
reached. I still can't figure that out, I got best results once I had
something that always tracks whenever there's anything to track. That way I
don't have to wait for it to respond, it's likely locked on before there's
enough amplitude to justify using as a gate threshold. I later learned that
RA Penfold had also used a Schmitt trigger to clean up, and also to prevent
lock to harmonic, but as I can use PC2, I get that anyway, because according
to teh datasheet (and my tests) it won't stray. I'll soon test it with a bass
guitar though, if it tracks that it out to track most things.

Anyway, caffiene or no caffiene, I've taken to rambling, so goodnight.

Lostgallifreyan · Oct 28, 2011

George Herold <gherold@teachspin.com> wrote in news:b908dd61-6c13-45d8-9023-
8447ae6f8336@m19g2000yqh.googlegroups.com:

That's OK, I'll try different values and measure on my own. I was
thinking I'd like to keep the capacitance as big as possible, since
then stray stuff is less important.

Could be a trade-off between one source of nonlinearity and another. I know
Winfield Hill likes to 'look the other way' but I suspect that trial and
error might often be the only way to get best results from a 4046 in many
specific contexts.

Stray capacitance might be ok anyway, if it won't change.

George Herold · Oct 28, 2011

On Oct 27, 8:28 pm, Lostgallifreyan <no-...@nowhere.net> wrote:

George Herold <gher...@teachspin.com> wrote in news:d420780a-8348-4cce-a2d4-
0480e27eb...@s7g2000yqa.googlegroups.com:

Do you have a digital 'scope? They have a so-so spectrum analyzer.
As far as phase locked loops, I don't know the 4046. But there are a
few different approaches. The AoE is as good a place to start as
any.

Indeed. That, and RM Marston's book on linear IC's got me very interested in
the 4046. I got most of my starting points from those two, and a bit of trial
and error.

No digital scope, but I think Phil Hobbs' post said I'd be ok with an analog
scope, if fast enough. (Mine is, I think, more than I'll need for this).

I'm very interested in the use of the 4046 as VCO. At the moment I'm
using one to drive a stepped sine thingie. I've been starring at the
spec sheet curves wondering if there's a sweet spot somewhere in R/C
space. At the moment I've got R=20k and C=470pF.

As far as I can tell, most 4046 VCO's will be a lot more linear with 100K to
1Meg with a supply voltage as high as they'll take safely, but the last thing
I am is an authoroty on this...

That's OK, I'll try different values and measure on my own. I was
thinking I'd like to keep the capacitance as big as possible, since
then stray stuff is less important.

Keeping the impedance low also helps keep electrostatic 'stuff' from
leaking in. Which is worrisome at low frequencies.

But if the chip likes a high impedance.. then I'll have to deal with
it.

George H.

Martin Brown · Oct 28, 2011

On 28/10/2011 01:58, Lostgallifreyan wrote:

Jim Thompson<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:s3uja71sjd1kluivcb5u9krh05l66cli6b@4ax.com:

What is it you're trying to do? Sub-bass? Chasing lights? What? I
did all that s!@# ~40 years ago ;-)

Whistle to MIDI convertor. Seriously. I actually got fairly good at
whistling. I can play a bass guitar fairly well now, and keyboard (with right

Actually that is something else I notice the latest version of Daqarta
will do "Pitch to midi" I have no idea how well or if it works or not.
Haven't bothered to download the newest version.

There was a realtime fundamental frequency display in earlier versions.

--
Regards,
Martin Brown

Lostgallifreyan · Oct 28, 2011

Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote in
news:TQsqq.3100$SW4.1774@newsfe08.iad:

Actually that is something else I notice the latest version of Daqarta
will do "Pitch to midi" I have no idea how well or if it works or not.
Haven't bothered to download the newest version.

There was a realtime fundamental frequency display in earlier versions.

The program doesn't work well for me, chews all CPU I have, and won't let me
select the channels I want for the sound output without using the main system
setting for that. I like that they still support all of Win32 though, and a
sound card was always a good idea for this, I made a small adapter to DC
couple input and output in a Layla 20 or 24 bit interface which makes awesome
lab (and laser scan control) gear considering eBay prices for those now.
Results easily worth ten times the price. I might get a limited amount of
realtime analysis from Goldwave, perhaps...

I don't know if my machine will cope with exotic realtime processes though,
Daquarta chewed 97% of it just generating a sine wave! I'd have to record to
Sound Forge and anaylse it afterwards. My next task will be simpler though, a
MIDI to CV converter and a MIDI keyboard to play a few oscillators, 4046 VCO,
LM311, etc... I think my ears will tell me soon enough what course to take
next.

Bill Sloman · Oct 28, 2011

On Oct 27, 6:35 pm, Phil Hobbs
<pcdhSpamMeSensel...@electrooptical.net> wrote:

On 10/27/2011 12:22 PM, Lostgallifreyan wrote:
> Phil Hobbs<pcdhSpamMeSensel...@electrooptical.net> wrote in
>news:4EA8A469.2040204@electrooptical.net:

<snip>

Thanks, that's interesting. Can you tell me more about that resistor that
helps the dead zone problem (which I also don't understand yet)? Is it
loading the output to ground?

Take a look at the NXP 74HCT9046 data sheet.

http://ics.nxp.com/products/hc/datasheet/74hct9046a.pdf

The part is claimed not to have the dead zone problem, which is
discussed in some detail on page 8 of the datasheet.

There's also a fair bit of detail on the relationship between the VCO
frequency and the controlling voltage furthter down the data sheet.

<snip>

--
Bill Sloman, Nijmegen

Lostgallifreyan · Oct 28, 2011

Lostgallifreyan <no-one@nowhere.net> wrote in
news:Xns9F8CA5BDE8E8Ezoodlewurdle@216.196.109.145:

My next task will be simpler though, a
MIDI to CV converter and a MIDI keyboard to play a few oscillators, 4046
VCO, LM311, etc... I think my ears will tell me soon enough what course
to take next.

Right now, I'm having a hard time knowing what the hell the VCO frequency IS
proportional to! With R1 at 47K, C1 at 10nF, I assumed that it was
proportional to voltage like damn near any VCO that wasn't designed to follow
the 1 volt per octave standard used for most musical synthesisers.

When I measure the voltage out of the MIDI to CV converter set to Hx per
volt, the output voltage scales up correctly, doubling per octave, so clearly
linear in proportion to frequency. The 4046 VCO isn't having any of it! Tones
a keyboard semitone apart at the top end are far less separated in frequency
than they are at the bottom end, and are actually MORE nonlinear than they
are if I try to feed a voltage of 1V per octave, i.e. proportional to pitch.
That obviously shouldn't work for a VCO that is supposed to be linear with
frequency, but hearing it become even worse when fed by the correct voltage
scaling makes no sense to me at all. The only thing that works as expected is
that the actual frequency is always the same for the same voltage.

To prove that the voltage really is ok, I fed it to an LM311 configged as a
voltage to frequency converter. The result was horrible as a musical
waveform, horrible in speed of response, but it DID track perfectly, I could
play fast scales on it that sounded like a rat-arsed little trumpet.

So as the 4046 VCO makes a clean square, and responds like a flea on crystal
meth, I REALLY need to know why it can't track a voltage that IS correctly
proportional to frequency. Again, this is no mere vague nonlinearity, it's
grotesque, more nonlinear even than the difference in proportion between
frequency and voltage.

Driver to drive?

Jim Thompson

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