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kryptic
Joined: Feb 16, 2007
Posts: 40
Location: somewhere
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 Posted: Tue Jul 17, 2007 11:05 am Post subject:
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Hey, that's great to hear Randal. You can put me down for 3. What an exciting time for DIYers here at E-M lately!  |
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prophei
Joined: Jan 27, 2007
Posts: 234
Location: san francisco, ca
Audio files: 4
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| Posted: Tue Jul 17, 2007 11:10 am Post subject:
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yeah, to get more specific, any good design of this type of osc that becomes available on pcb will force me to buy between 3 or 4 pcb's....
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endif
Joined: Jul 14, 2006
Posts: 138
Location: Reno, NV
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guitarfool
Joined: Feb 26, 2007
Posts: 161
Location: Maryland
Audio files: 8
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| Posted: Wed Jul 18, 2007 4:30 pm Post subject:
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| ENDIF wrote: |
*dammit, this is turning into a serious addiciton..* |
I'll take 4.
I don't have a problem - I can quit! I've done it lots of times. 
The wave shaping circuit for this oscillator was borrowed from the EN76 Option 2 VCO, as I recall. The saw modulation is very nice!
But just to stir the pot, in keeping with the true spirit of through-zero oscillation, wouldn't you want the saw to change to a ramp when you go through zero? The Cynthia Zero-oscillator doesn't appear to do this, although it does have quadrature outputs. I suspect this was done in a manner similar to Tom Henry's Quadrature Function Generator in Electronotes #122. Check out the Thomas Henry's Designs forum, for yet ANOTHER PCB  |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Wed Jul 18, 2007 4:56 pm Post subject:
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| guitarfool wrote: |
The wave shaping circuit for this oscillator was borrowed from the EN76 Option 2 VCO, as I recall. The saw modulation is very nice! |
Hmmm... I don't see any waveshapers. Or saws either.
I'm pretty sure we're discussing the Jan Hall VCO in EN#65 p.11, also appearing in the Prefered Circuit collection.
Which one are you refering to?
Ian |
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guitarfool
Joined: Feb 26, 2007
Posts: 161
Location: Maryland
Audio files: 8
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| Posted: Wed Jul 18, 2007 5:23 pm Post subject:
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| Oops, my mistake. I thought the discussion was about the OTHER through-zero oscillator that's also in the Builder's Guide and Preferred Circuits - 4 pages later - from EN#129. |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Wed Jul 18, 2007 5:40 pm Post subject:
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| guitarfool wrote: | | Oops, my mistake. I thought the discussion was about the OTHER through-zero oscillator that's also in the Builder's Guide and Preferred Circuits - 4 pages later - from EN#129. |
No, I guess it's my mistake. My version of the Prefered Circuits (1980) does not have the EN#129 TZVCO. I didn't realize that there was a later edition. [Bernie dropped my subscription around then, apparantly because of a postal problem, and didn't respond when I tried to contact him. So I missed some material, which was replaced just a couple of years ago.]
But how could it be the EN#129 unit if Bernie said it was Charlie Thompson's design?  |
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Randaleem
Joined: May 17, 2007
Posts: 456
Location: Northern CA, USA
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Posted: Wed Jul 18, 2007 6:18 pm Post subject:
Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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Hi,
Today I've been reading up on TZ in general and having a look at what's already offered commercially. This is an interesting project!
Andrew F, Thank you for the opportunity to follow your footsteps.
Ian,
Thank You for the suggestion to contact Bernie Directly. FWIW, It's the EN#129 TZVCO that I'm going to start with in creating this PCB/module. Not sure if it will stay "stock" or get some additions yet. Still bouncing some ideas around between my ears<G>.
Guitar,
I am the one currently offering an updated Thomas Henry Quadrature Function generator PCB. Yes, I've been thinking about it in relation to this circuit.
Thomas would have to approve any further use of his circuit first.
I've recently done an LFO with a VC ramp to tri to saw for use with the mini-and EM Klee Seq, and it's funny you mention that in regard to the TZVCO.
I'd like to hear any and all wishlist thoughts for this PCB/Module. Can't say that they'll be added; but I can securely say that I can't add things I don't know are desired 
I'd also like to give it a name. Here's a few I've come up with:
Z-Øsc (Zee-Ahsk) OscillatØr (Ah-sil-lay-TOR)
VCØ (Vee-cee-ZERO) ZØSC (ZahSK, or Zohsk)
Let me know what you think?
Randal |
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guitarfool
Joined: Feb 26, 2007
Posts: 161
Location: Maryland
Audio files: 8
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| Posted: Wed Jul 18, 2007 6:21 pm Post subject:
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Oh, great - the plot thickens.
Bernie presented the reversing and rectifier part of the EN#129 TZVCO in EN#127, where he also mentions a method by Douglas Kraul from EN#62.
If there was another design by Charlie Thompson.....
Now I feel compelled to search the whole collection to find it.
On a lighter note - I got your 5-pulser boards today. Thanks! |
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Randaleem
Joined: May 17, 2007
Posts: 456
Location: Northern CA, USA
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| Posted: Wed Jul 18, 2007 6:26 pm Post subject:
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| frijitz wrote: | | But how could it be the EN#129 unit if Bernie said it was Charlie Thompson's design? |
Hi Ian,
Bernie responded with three items after my request; one was a discrete OTA by Charlie Thompson from EN#62.
No reference to CT is made in the EN#129 paper. Douglas Kraul and EN#62 are mentioned. The TZVCO is apparantly an update of the Kraul Circuit.
Randal |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Thu Jul 19, 2007 5:32 am Post subject:
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OK, I think I got it now. The EN#129 VCO is the one that is being considered here, and it appeared in an update to the Prefered Circuit Collection, which I don't have. The circuit originated from Doug Kraul's design in EN#62, which Bernie misremembered as being from Charlie Thompson, who also contributred to EN#62.
Whew! These senior moments are lasting longer and longer all the time.  |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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Posted: Thu Jul 19, 2007 5:46 am Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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| Randaleem wrote: | | ...I've recently done an LFO with a VC ramp to tri to saw for use with the mini-and EM Klee Seq, and it's funny you mention that in regard to the TZVCO... |
Just out of curiosity, I was wondering how you do the ramp-to-tri. Is is a morphing (tilting the saw's edge) or a mixing? I discovered a novel way to do the morphing a few years back:
http://home.comcast.net/~ijfritz/sy_cir10.htm
I haven't seen anyone else do it this way for synth applications.
Ian |
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factus10
Joined: Jun 20, 2007
Posts: 158
Location: Buffalo, NY
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Posted: Thu Jul 19, 2007 7:16 am Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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| frijitz wrote: | Just out of curiosity, I was wondering how you do the ramp-to-tri. Is is a morphing (tilting the saw's edge) or a mixing? I discovered a novel way to do the morphing a few years back:
http://home.comcast.net/~ijfritz/sy_cir10.htm
I haven't seen anyone else do it this way for synth applications. |
Holy jesus. Not to hijack, but would you consider offering that as a pcb? I know I'd want at least one. |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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Posted: Thu Jul 19, 2007 11:06 am Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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| factus10 wrote: | | Not to hijack, but would you consider offering that as a pcb? I know I'd want at least one. |
Thanks, but probably not. There has been almost no interest in this one over the years. Looks like everyone is saturated with boards right now, anyway, so I don't have plans to do any more for the time being.
But let's get back to the much more interesting TZVCO discussion. |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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Posted: Thu Jul 19, 2007 11:57 am Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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| Randaleem wrote: |
Today I've been reading up on TZ in general and having a look at what's already offered commercially. This is an interesting project! |
Yes, indeed.
One thing you might want to think about. I seem to remember hearing a criticism that the EN129 switching approach might have problems with chattering at the switching point for slow modulation signals. I'm not sure why you would even want to use very slow modulation, and I have no idea if this is a real problem or just something somebody was worrying about, but you might have a careful look at this aspect if you do a breadboard test. It looks to me like the Tillman or Wamsley approaches might get around any such problem.
I've been thinking for some time about adding TZFM to my super high-performance VCO:
http://home.comcast.net/~ijfritz/sy_cir4.htm
This doesn't incorporate a resettable flip-flop, but the required logic circuitry to reset all the switches shouldn't be too difficult to figure out.
All that's required is a negative pulse applied to the comparitors' inputs if the ramp is decreasing and vice versa. The ramp direction is given by either of the comparitor outputs, so all the is needed is a bipolar pusler (maybe an s-pulse) and another pair of analog switches to select the correct one.
Another project for the queue .  But I have been wanting to look at a simplified, less expensive version of this VCO anyway, so now I have some more motivation.
BTW, I fought off and on for years to get the OTA-based tri VCO approach to work accurately, but never had much luck. You may read my scree against it at the above link. Oh, I now see that I forgot to mention that OTA's don't have linear Iabc responses, so it is quite difficult to get good tracking -- something I would think you might want for serious FM work.
Ian |
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Randaleem
Joined: May 17, 2007
Posts: 456
Location: Northern CA, USA
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Posted: Thu Jul 19, 2007 1:45 pm Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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| frijitz wrote: | Just out of curiosity, I was wondering how you do the ramp-to-tri. Is is a morphing (tilting the saw's edge) or a mixing?
Ian |
Hi Ian,
It's a morph. I haven't seen it done the way I have; but it sure seemed obvious (whilst standing on the shoulders of Giants!) to me. Don't really want to say more until the SLO (Sample Lag Oscillator) LFO module for the Mini-Klee and EM-Klee is released. FWIW, the SLO is a nice LFO even without a Klee.
Randal |
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v-un-v
Janitor
Joined: May 16, 2005
Posts: 8932
Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1
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Posted: Thu Jul 19, 2007 3:02 pm Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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| Randaleem wrote: | OscillatØr (Ah-sil-lay-TOR)
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Jamaican Accent?!?
_________________
ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN. |
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Randaleem
Joined: May 17, 2007
Posts: 456
Location: Northern CA, USA
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Posted: Thu Jul 19, 2007 3:11 pm Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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| v-un-v wrote: | | Randaleem wrote: | OscillatØr (Ah-sil-lay-TOR)
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Jamaican Accent?!? |
V,
Did I make an accent?
No, that's a strikethrough. With an accent, it'd look like this: OscillatÒr
 Randal |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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Posted: Thu Jul 19, 2007 3:14 pm Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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| Randaleem wrote: | | I'd also like to give it a name. |
Reverserator? |
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tomcat
Joined: Oct 14, 2005
Posts: 141
Location: earth
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| Posted: Thu Jul 19, 2007 4:28 pm Post subject:
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Ice-Olator 
P.S. 0 degrees celsius is the freezig point for water |
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endif
Joined: Jul 14, 2006
Posts: 138
Location: Reno, NV
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mono-poly
Joined: Jul 07, 2004
Posts: 937
Location: Rotterdam, Netherlands
Audio files: 2
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| Posted: Fri Jul 20, 2007 3:42 pm Post subject:
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| OMG dunno what it's gonna be but i am in! |
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endif
Joined: Jul 14, 2006
Posts: 138
Location: Reno, NV
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guitarfool
Joined: Feb 26, 2007
Posts: 161
Location: Maryland
Audio files: 8
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| Posted: Sat Jul 21, 2007 10:01 pm Post subject:
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Looks like Bernie has posted the original article.
Go here: http://electronotes.netfirms.com/free.html and scroll down to the bottom "Electronotes 129 Through-Zero VCO" |
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Nosferatu
Joined: Jul 27, 2007
Posts: 234
Location: Planet Rock.
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Posted: Fri Jul 27, 2007 2:20 pm Post subject:
Re: Thru-Zero VCOs
Subject description: Thru-Zero VCO pro PCB in the works! |
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del
Last edited by Nosferatu on Mon Nov 26, 2007 3:28 pm; edited 2 times in total |
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