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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
Audio files: 24
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Posted: Sun May 27, 2007 11:00 am Post subject:
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Quote: | also liked the definition from the urban dictionary, which states that a gnat's ass is about one tenth of a skosh (which is equal to approximately one nudge of the dial, amounting to something much less than a pussy hair). |
Thats f---ing funny man !!!!!
Thanks for the laughs guys !
Bill |
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Coriolis
Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark
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Posted: Sun May 27, 2007 12:01 pm Post subject:
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Ahem:
One question - I've got 1k tempco's but no 2k. If I want to use those, I'll have to use a 50K resistor instead of 100k on the 1v/oct input, right?
But what about the other inputs? Will it matter? Would I have to halve both the pot- and series resistor values (say, on the "coarse" input - R35, R28 and R44 will be 50k, 50k and 1M1 respectively). Or what? What happens if I don't?
Man, I've got 2sa768's, 1000pf polystyrene caps, a couple 3080's...
I'm building one of these!
C |
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Scott Stites
Janitor
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Mon May 28, 2007 12:37 am Post subject:
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Hey Coriolis,
Y'know, I never know the answer to this one. Thomas? Bill? Fonik? Anyone?
If the 1K doesn't work, maybe I can help get you set up with a 2K tempco.
Cheers,
Scott _________________ My Site |
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
Audio files: 26
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Posted: Mon May 28, 2007 4:24 am Post subject:
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Coriolis wrote: | Ahem:
But what about the other inputs? Will it matter? Would I have to halve both the pot- and series resistor values (say, on the "coarse" input - R35, R28 and R44 will be 50k, 50k and 1M1 respectively). Or what? What happens if I don't?
C |
I'm pretty sure that if you don't change the series resistor(s) the associated input will give half the range it would with a 2k tempco. The Coarse control would provide, say, a 2 octave range instead of 4 or whatever, the Fine contol would be very fine, an lfo or envelope on the Exp FM would provide half as much frequency sweep.
The pot values do not matter much -- they act as voltage dividers. They affect the loading on the circuit driving them and the low impedance output of opamps provides plenty of drive. I wouldn't use lower than 20k or so in a system, though, just to be safe. |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Mon May 28, 2007 4:46 am Post subject:
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i had the same question when building the SN-voice, can't remember who (it will be somewhere on the SN-voice thread) said putting two 1k tempcos in series, gives you 2k and the temp comp rating doesn't change, the message finished with - trust me!
Anyway i did.
as far as my worn out tin ears can tell its fine. |
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State Machine
Janitor
Joined: Apr 17, 2006 Posts: 2809 Location: New York
Audio files: 24
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Posted: Mon May 28, 2007 8:21 am Post subject:
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Quote: | Ahem:
One question - I've got 1k tempco's but no 2k. If I want to use those, I'll have to use a 50K resistor instead of 100k on the 1v/oct input, right?
But what about the other inputs? Will it matter? Would I have to halve both the pot- and series resistor values (say, on the "coarse" input - R35, R28 and R44 will be 50k, 50k and 1M1 respectively). Or what? What happens if I don't? |
If you want the circuit to behave exactly as it did with the 2K TEMPCO feedback resistor when using the 1K unit, you will need to half all the input resistors (R26,R27,R28,R44,R46) that go to the op-amplifiers summing junctions. The pots can remain the same values.
Bill |
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Coriolis
Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark
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Posted: Mon May 28, 2007 10:28 pm Post subject:
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Thanks for the advice, people!
I think I'm going to use 50k (49.9k) resistors then. I've got a bunch of 1k 3000ppm tempco's, but if I use two at a time, they'll be used up pretty fast...
Great that I don't have to use different pots - I have loads of the 100k variety from futurlec!
Great to be learning!
C |
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Thomas Henry
Joined: Mar 25, 2007 Posts: 298 Location: Southern Minnesota
Audio files: 2
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Posted: Wed May 30, 2007 10:31 pm Post subject:
Re: Thomas Henry Strikes Again Subject description: Another very cool VCO by the Man from Mankato |
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Scott Stites wrote: | From way up north, Mankato way, land of a thousand lakes... |
Ahem...as our license plates proudly proclaim: Land of Ten Thousand Lakes.
Hey Scott, can I interest you in a VCO which is perfectly in tune over one octave?
Thomas Henry |
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Coriolis
Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark
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Posted: Fri Jun 01, 2007 5:37 am Post subject:
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Yeah, I believe the "single" thousand lakes land is Finland...
C |
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Scott Stites
Janitor
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Fri Jun 01, 2007 6:20 am Post subject:
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Any state that can wriggle out of a Jesse "The Body" Ventura headlock has got my respect, no matter how many lakes it's got!
Now, if Kansas had just one natural lake, I'd be surprised......
We've got cow ponds. Does that count? _________________ My Site |
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