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Tim Servo
Joined: Jul 16, 2006
Posts: 924
Location: Silicon Valley
Audio files: 11
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 Posted: Wed Dec 23, 2009 2:02 pm Post subject:
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| sduck wrote: | | Several things - one is that these are expensive pots, but even so they've got that loosy feel that the cheaper bourns pots have. And I don't know if one of mine is broken or defective, but the amount of torque required to turn my init freq pot is directly related to how tightly I tighten the mounting nut - in other words, if I tighten it up as much as I'd like, the thing is nearly impossible to turn, so I need to back off the torque a bit. Odd... |
Hey Sduck,
That definitely sounds odd. One thing you might try is putting a small spacer between the body of the pot and the panel (so you have pot - spacer - panel - mounting nut). You can use a washer or even another mounting nut as a spacer. Actually, I'd probably go with another mounting nut, so that the clamping force isn't being transfered to the body of the pot. What I'm thinking is that the body of the pot is getting squished against the back side of the panel as you tighten the mounting nut, and this is causing some mechanical twisting or compression inside the pot. It may also be that the 'collar' that holds the pot shaft is broken, and so it clamps down on the shaft as you tighten things up. I'd take a really close look at that pot and make sure it's okay, and then maybe try the second mounting nut trick and see if that cures the problem.
Tim (let the "tight shaft" jokes begin!) Servo |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Wed Dec 23, 2009 2:35 pm Post subject:
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| neandrewthal wrote: | I have LM336 2.5v regulators in there  So, I'm just curious, is this enough to make it completely not work? |
Not for sure, but I think you should see some kind of oscillations. But it won't work correctly.
Of course, help is available  . But I'll be having some down time over the next couple of weeks.
Ian |
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sduck
Joined: Dec 16, 2007
Posts: 459
Location: Nashville
Audio files: 5
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| Posted: Wed Dec 23, 2009 8:53 pm Post subject:
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Thanks Tim! But it seems to be ok the way it is - the pots not twisting or anything, it's holding fine, and the knob is currently turning fine. It's just a matter of loosening it up a little bit - not so much that the thing gets too loose.
I'm considering building another one of these, so this one is sort of a test bed - it's certainly had more than it's share of problems. Including one I haven't even brought up yet because I just don't have the time to deal with it (and it's probably just another wiring error). |
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neandrewthal
Joined: May 11, 2007
Posts: 672
Location: Canada
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| Posted: Thu Dec 24, 2009 2:18 am Post subject:
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| frijitz wrote: | | neandrewthal wrote: | | I have LM336 2.5v regulators in there So, I'm just curious, is this enough to make it completely not work? |
Not for sure, but I think you should see some kind of oscillations. But it won't work correctly.
Of course, help is available . But I'll be having some down time over the next couple of weeks.
Ian |
Cool, thanks. I probably won't get the right parts until the holiday rush is over anyway, so I'll see if I can find anything else wrong then and ask if I'm stumped.
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" I went through quite a few trannies til I found one I liked" - Wild Zebra |
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neandrewthal
Joined: May 11, 2007
Posts: 672
Location: Canada
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| Posted: Thu Dec 31, 2009 1:15 pm Post subject:
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Ok, so I got the 5v regulators working properly. Still nothing
Next I started following the sduck procedure for stillborn Teezers. Got 15v on the A5-A10 line I don't know why, but the zener diodes were shorted and I replaced them with new ones. Got my 12v(11.4 actually), but still not a peep.
The expo and A3 seem to be working.
Continuing along:
A2-6: Nothing
U2-2: 2.2v
U2-3: 2.7v
U2-7: -6.3v
U3-2: -4.6v
U3-3: -6.4v
U3-7: 5.2v
This is close to what sduck got except that U3 is high instead of low.
Next, the D2,D4,D6,R28,Q4,Q5 node - -4.5v.
At this point it looks like the sduck procedure will not help me anymore, but I`m very glad you guys went through it in this thread rather than in private. I think I`m pretty close now.
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neandrewthal
Joined: May 11, 2007
Posts: 672
Location: Canada
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| Posted: Fri Jan 01, 2010 12:06 am Post subject:
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Well, I replaced the LM311s and it works
Now let`s see if I can get through the calibrations.
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Fri Jan 01, 2010 10:05 pm Post subject:
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| neandrewthal wrote: | | Well, I replaced the LM311s and it works. |
Hmmm ... that seems strange. Are the new ones from a different batch? I did have some trouble with a batch that wouldn't work at one point. Are the old ones actually buzzed?
Ian |
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neandrewthal
Joined: May 11, 2007
Posts: 672
Location: Canada
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| Posted: Sat Jan 02, 2010 7:36 pm Post subject:
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| frijitz wrote: | | neandrewthal wrote: | | Well, I replaced the LM311s and it works. |
Hmmm ... that seems strange. Are the new ones from a different batch? I did have some trouble with a batch that wouldn't work at one point. Are the old ones actually buzzed?
Ian |
One was from the same batch of LM311P from TI that I have in there now. The other was a leftover from an old batch of LM311N from National. I`m not sure which one was acting up since I swapped them both out at once.
The calibrations went about as well as I could expect them to without a scope. It tracks well and I was able to get a triangle and sine that sound as good as any I`ve heard.
Now as soon as Digi-key receives their 2 week late shipment of 2134`s I`ll try to get the second one up and running.
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alcofribas
Joined: Oct 03, 2008
Posts: 22
Location: Eastern France
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| Posted: Mon Jan 04, 2010 4:13 pm Post subject:
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This might have nothing to do with your problems, but I went through a whole bunch of comparator spec sheets today and noticed that TI 311s have faster specs than generic 311s.
Alcofribas |
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sduck
Joined: Dec 16, 2007
Posts: 459
Location: Nashville
Audio files: 5
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| Posted: Sun Jan 10, 2010 6:33 pm Post subject:
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Last problem with this thing. I promise.
Apparently my sync depth knob isn't working. I can't tell any change in behavior at any setting. There are two possibilities - 1. I'm not fully understanding how it's supposed to work, and am testing it wrong ...or 2. it just doesn't work.
In an earlier debugging post you mentioned that I must have it wired wrong - but I've rechecked everything (several times!) - I have the CW end of the pot attached to ground, the middle connected to slev2, and the CCW end to slev1. No shorts or anything I can find - the pot is a nice 10K spectrol, and is reading correctly on my DMM as I turn the knob. As I mentioned earlier, A9 pin 2 is reading 3.8v with the knob at 0, changing to 0v with the knob at 10.
Any ideas? |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Mon Jan 11, 2010 11:46 am Post subject:
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| sduck wrote: | | Apparently my sync depth knob isn't working. I can't tell any change in behavior at any setting. |
This should be straightforward to track down.
First put your scope on the comparator outputs A9a-1, A10-6. Both should be swinging rail-to-rail.
Ian |
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sduck
Joined: Dec 16, 2007
Posts: 459
Location: Nashville
Audio files: 5
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| Posted: Mon Jan 11, 2010 8:21 pm Post subject:
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| Hmm, not quite right here. At A9 pin 1 I'm getting a square wave, and A10 pin 6 is a steady voltage - 11.4v. Hope I'm reading the right pins! |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Mon Jan 11, 2010 9:51 pm Post subject:
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| sduck wrote: | | Hmm, not quite right here. At A9 pin 1 I'm getting a square wave, and A10 pin 6 is a steady voltage - 11.4v. Hope I'm reading the right pins! |
So A10 isn't firing. The Sync In signal just has to cross 0.65V every cycle. I guess check to be sure you see the sync signal at the R125/R126 junction and that pin2 is at .65V. Other than that, one of the resistors around A10 might be wrong, e.g. the 4.7k, 47k and 470k might have gotten mixed up. |
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neandrewthal
Joined: May 11, 2007
Posts: 672
Location: Canada
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| Posted: Wed Jan 13, 2010 6:19 pm Post subject:
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To avoid hijacking the analog FM thread at MW, I'll reply to this post here:
| frijitz wrote: | This is a very interesting question. I've done some recent work investigating whether Chowning-type FM can be done in analog, in conjunction with the development of my through-zero VCO (The Teezer). I have found -- using modern, accurate VCO design -- that it takes only a small amount of sync to make Chowning-type dynamic-depth FM with huge modulation indices workable. The sync modifies the waveform slightly, of course, but so far this doesn't seem to me to be a large drawback, since only a small amount of soft sync is needed. This is something people will have to decide for themselves in the context of their own needs, but I think there is a lot of potential for useful, deep FM patches here. Of course, people who do not believe in using accurate equipment will not be able to test this directly themselves.
The development of the Teezer is documented on a thread at e-m. I have put up there some demos of wide sweeps of deep through-zero FM (around page 11).
http://electro-music.com/forum/topic-29149-25.html
Ian |
Ian, I did something really stupid. I thought the sync amount knob on the Teezer was an attenuator so I left it off to save space. I didn't realize until I was wiring it that it's an integral part of the circuit. So, I have to hardwire a divider circuit into it to replace the pot, but this begs the question. What setting of the sync amount would be the most useful for the kind of things you describe above, or does it require tweaking every time you change another control? (hence the use for the pot which I ignored) I will have two Teezers, so I could have a different setting on each of them, but I'm still SOL if it's something that requires finding the sweet spot dpeending on your patch.
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Wed Jan 13, 2010 8:15 pm Post subject:
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| neandrewthal wrote: | | So, I have to hardwire a divider circuit into it to replace the pot, but this begs the question. What setting of the sync amount would be the most useful for the kind of things you describe above |
Well, I like to use the least sync necessary for the frequency ratio and frequency range I'm trying to use.
Is there any way you can squeeze a small toggle switch in? Then you could try using settings of 20% and 100% for soft and hard sync.
Ian |
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neandrewthal
Joined: May 11, 2007
Posts: 672
Location: Canada
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| Posted: Wed Jan 13, 2010 11:24 pm Post subject:
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| frijitz wrote: |
Is there any way you can squeeze a small toggle switch in? Then you could try using settings of 20% and 100% for soft and hard sync.
Ian |
Unfortunately, no room for a switch. It's real tight in there since I squeezed 2 of them on a 2U panel.
I have a new idea, though. I could steal the fine tune pot on one of the Teezers. For general purposes I don't really need a fine tune on both. With a bit of fiddling I can usually get exactly where I want with the coarse alone anyway.
I'm not sure how this would pan out with touchy FM patches. In a soft-synched FM patch like you described is there anything I'd be missing by only having fine control over the master VCO?
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sduck
Joined: Dec 16, 2007
Posts: 459
Location: Nashville
Audio files: 5
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| Posted: Thu Jan 14, 2010 6:49 pm Post subject:
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Ok, found it. It was another 22 ohm resistor where a 22K should have been - R131. Again, an easy fix, and now the thing has a whole new realm of weird sounds available. Thanks for the help in finding it! As far as I can tell it's fully functional now! Yay!
And now a big question, and not just for Ian: show me your patches! I definitely know how to experiment a lot, but am still having a perceptual problem getting into some of the finer concepts involved with this module. So perhaps the easiest/best way is to show me what it can do - how do you use this thing? |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Thu Jan 14, 2010 7:57 pm Post subject:
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| sduck wrote: | | As far as I can tell it's fully functional now! Yay! |
| Quote: | | So perhaps the easiest/best way is to show me what it can do - how do you use this thing? |
You might want to check out some of the discussion going on over at muff's:
http://www.muffwiggler.com/forum/topic-11481.html
Ian |
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Tasmanian Alkaloid
Joined: Jun 29, 2008
Posts: 116
Location: Isle De Mort
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| Posted: Fri Jan 15, 2010 9:01 am Post subject:
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| neandrewthal wrote: | | frijitz wrote: |
Is there any way you can squeeze a small toggle switch in? Then you could try using settings of 20% and 100% for soft and hard sync.
Ian |
Unfortunately, no room for a switch. It's real tight in there since I squeezed 2 of them on a 2U panel.
I have a new idea, though. I could steal the fine tune pot on one of the Teezers. For general purposes I don't really need a fine tune on both. With a bit of fiddling I can usually get exactly where I want with the coarse alone anyway.
I'm not sure how this would pan out with touchy FM patches. In a soft-synched FM patch like you described is there anything I'd be missing by only having fine control over the master VCO? |
If you have 10-turn pots for the Initial Frequency & Coarse, you probably won't need a fine tune pot. I had one when i first built it, but took it out & haven't missed it. |
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neandrewthal
Joined: May 11, 2007
Posts: 672
Location: Canada
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| Posted: Fri Jan 15, 2010 4:25 pm Post subject:
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I'm not a big fan of 10 turn pots actually, but I do have a big 1.3 inch knob for the coarse tune and I can tune it for unison with another oscillator in a couple seconds with that alone. I'm just not sure how well it would work for a dual teezer sync fm patch. I guess I could just use the fine tune on the master VCO to get the exact ratio I want, but then the overall pitch goes off. I'll just have to make sure that I tune everything to the teezers rather than the other way around.
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zthee
Joined: Feb 20, 2008
Posts: 414
Location: Stockholm
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| Posted: Wed Mar 10, 2010 6:12 pm Post subject:
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I'd like some feedback on this panel.
And never mind the pitch scaling around the large knobs - it's for the graphics - not usefull 
The Voltage Controlled Mod. Section is just a VCA connected to the lin. fm input.
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Wed Mar 10, 2010 7:07 pm Post subject:
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| zthee wrote: | | I'd like some feedback on this panel. |
Very nice. Do you want to have both AC and DC coupling available for the Linear FM?
Ian |
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Luka
Joined: Jun 29, 2007
Posts: 1003
Location: Melb.
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zthee
Joined: Feb 20, 2008
Posts: 414
Location: Stockholm
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| Posted: Thu Mar 11, 2010 12:04 am Post subject:
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| frijitz wrote: | | zthee wrote: | | I'd like some feedback on this panel. |
Very nice. Do you want to have both AC and DC coupling available for the Linear FM?
Ian |
Thank you!
What is the advantage of DC coupling the linear FM input? AC coupled will make it swing ±? Which is needed for that "original" FM sound?
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Sound
Joined: Jun 06, 2006
Posts: 842
Audio files: 1
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| Posted: Thu Mar 11, 2010 4:30 am Post subject:
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Very very nice Luka. Pretty. You have there a very powerful module.
What ist hat pulse output? |
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