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ejr27233
Joined: Feb 08, 2010 Posts: 52 Location: UK
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Posted: Sun Feb 26, 2012 6:41 am Post subject:
2k Tempco advice Subject description: Options to replace 2k tempco |
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I'm about to build 2 Buchla 258ish VCO's and need 2k Tempco's.
I've got 1k ones so the options are....
a, Put 2 1k tempco's in series
b. Put a 1k tempco and a 1k 1% metal film resistor in series.
or at a push
c, Order 2k tempco's from USA (not keen to do)
Which is the best option???
Any advice greatfully recieved |
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Sebo
Joined: Apr 27, 2007 Posts: 564 Location: Argentina
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Posted: Sun Feb 26, 2012 6:55 am Post subject:
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I think that two 1K tempcos in series will work OK. The x0xbox uses two 1K tempcos in series.
1K tempco + 1K metal film will not work for sure, as the temperature coeficient will be a lot lower than needed. _________________ Sebo
---------------------------------------
My Music:
https://www.facebook.com/cosaquitos/ |
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ejr27233
Joined: Feb 08, 2010 Posts: 52 Location: UK
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Posted: Fri Mar 02, 2012 11:39 am Post subject:
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Thanks for your help
Regards
John |
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L´Andratté
Joined: Sep 23, 2012 Posts: 150 Location: Hamburg, Germany
Audio files: 5
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Posted: Sat Jan 19, 2013 4:41 pm Post subject:
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Funny, I have the same question-
Since those tempcos are not really cheap, wouldn´t it be possible to just lower the input resistors from 100 to 47k (same relation gain 1/50)?
I´ll try it...
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rogerlatur
Joined: Dec 22, 2012 Posts: 118 Location: france
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Posted: Mon May 20, 2013 5:26 am Post subject:
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L´Andratté wrote: | Funny, I have the same question-
Since those tempcos are not really cheap, wouldn´t it be possible to just lower the input resistors from 100 to 47k (same relation gain 1/50)?
I´ll try it... |
I am curious if you did try?
Is there any replacement then? |
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L´Andratté
Joined: Sep 23, 2012 Posts: 150 Location: Hamburg, Germany
Audio files: 5
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Posted: Mon May 20, 2013 5:52 am Post subject:
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Yes and no...
I did build it and it gave exponential response and mediocre scaling was there, but not optimal, maybe due to other things? I don´t know, I guess the problem with the 47k is about the input impedance, maybe there´s some tiny voltage loss?
The difficulty might be the same cv would give different notes from different osc.s! {EDIT: check next post}
Sorry I´m only autodidactic halfwit
Good reading:
*** ELECTRONOTES S019:scroll down here
http://electronotes.netfirms.com/free.htm
***http://www.uni-bonn.de/~uzs159/index.html
***first article under
"Projects and Misc Files"
http://home.comcast.net/~ijfritz/misc_lnk.htm Last edited by L´Andratté on Mon May 20, 2013 6:31 am; edited 1 time in total |
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L´Andratté
Joined: Sep 23, 2012 Posts: 150 Location: Hamburg, Germany
Audio files: 5
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Posted: Mon May 20, 2013 6:29 am Post subject:
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Check especially the 2nd link halfway down, it´s there!
54k:1k at 1% tolerance! |
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rogerlatur
Joined: Dec 22, 2012 Posts: 118 Location: france
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Posted: Wed May 22, 2013 10:53 am Post subject:
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L´Andratté wrote: | Check especially the 2nd link halfway down, it´s there!
54k:1k at 1% tolerance! |
I see.
This page is very instructive, and I will check also the other links. Thank you very much! |
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