Author |
Message |
jean bender
Joined: Feb 21, 2010 Posts: 139 Location: france
|
Posted: Tue Mar 29, 2011 7:29 am Post subject:
Changing pots values |
|
|
hi everybody..
Most of schematics use pots which have values between 100k and 1meg.
I've got a huge stock of 50k pots, and i think it should be stupid to not use them, and buying other pots.
My question is : What should i do when i'm building an osc, for exemple, in order to have a "normal" response ?
yesterday i tried to make some osc from a 4093. It was working, but when i changed my pots for 1meg ones, for exemple, the coarse was much better with them than with 50k.
At the moment, i'm looking after typical osc : 0.1uf caps, 10k res with the pot in feedback loop...
I don"t think that i have to change caps values, since it's them which give the general pitch. Maybe using a bigger resistance ? In parallel of the pot ?
thanks for any trick !
cordially ! _________________ http://h.a.k.free.fr/
www.electroncanon.org |
|
Back to top
|
|
|
slacker
Joined: Nov 18, 2007 Posts: 301 Location: England
Audio files: 11
G2 patch files: 1
|
Posted: Tue Mar 29, 2011 10:06 am Post subject:
|
|
|
The frequency of these oscillators is roughly 1/(resistance x capacitance) so if you make the resistance smaller you need to make the capacitor larger by the same amount to keep the same frequency.
If a design uses a 1Meg pot and a 0.1uF cap and you want to use a 50k pot you'd need to make the cap 20 times bigger, so you could use a 2.2uF cap. If there's a resistor in the feedback loop as well as the pot you need to make this 20 time smaller so something like 470 Ohm. |
|
Back to top
|
|
|
jean bender
Joined: Feb 21, 2010 Posts: 139 Location: france
|
Posted: Tue Mar 29, 2011 11:22 am Post subject:
|
|
|
ok thanks, i think it will help me a lot !!
Where can i find some knowledge about the way to build osc like these ? i mean, this math theory ?
Well, thanks for all !! _________________ http://h.a.k.free.fr/
www.electroncanon.org |
|
Back to top
|
|
|
Kabzoer
Joined: Feb 07, 2011 Posts: 82 Location: Belgium
|
|
Back to top
|
|
|
jean bender
Joined: Feb 21, 2010 Posts: 139 Location: france
|
Posted: Thu Mar 31, 2011 4:59 am Post subject:
|
|
|
You're right !!
I oftently should look at these datasheets... lots of interesting things in these documents !
_________________ http://h.a.k.free.fr/
www.electroncanon.org |
|
Back to top
|
|
|
Glitch-Militia
Joined: Apr 25, 2011 Posts: 25 Location: Europe
|
Posted: Wed Apr 27, 2011 12:59 am Post subject:
|
|
|
I have a question regarding this as well.
I have recently "slaughtered" a few large mixers for parts, thus I have about [1000] pots, mainly 10 KΩ logarithmic and linear.
Is it possible to use the linear 10 KΩ in the Baby10 sequencer instead of the 100KΩ and how would I do this ? |
|
Back to top
|
|
|
tjookum
Joined: May 25, 2010 Posts: 360 Location: Netherlands
Audio files: 26
|
Posted: Wed Apr 27, 2011 6:25 am Post subject:
|
|
|
nice find!
And yeah, if you are using the potentiometers as a voltage divider to generate a control voltage from each step you can use any pot you like. I do recommend >10K just to be on the safe side.
A voltage divider works with the ratio of the resistance between pin1 and the wiper and pin2 and the wiper. Basically if the pot is turned 1/10th it means that the ratio is 1:9 and it will let 10% of the signal go through. Try ading a voltage divider as a volume control to a simple audio circuit, you will find that the value doesn't matter. _________________ There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.
Hunter S. Thompson
movies
noise |
|
Back to top
|
|
|
Glitch-Militia
Joined: Apr 25, 2011 Posts: 25 Location: Europe
|
Posted: Thu Apr 28, 2011 12:03 am Post subject:
|
|
|
Thanks tjookum for an informative post. |
|
Back to top
|
|
|
Glitch-Militia
Joined: Apr 25, 2011 Posts: 25 Location: Europe
|
Posted: Fri May 06, 2011 12:40 am Post subject:
|
|
|
tjookum wrote: | nice find!
|
As icing on the cake i also pulled:
2 x MN3005 BBD's
2 x MN3207 BBD's + 2 x MN3102
2 x NE570N Compandors
M5207L01 Dual VCA
Not counting the ridiculus amount of op-amps.
And I'm not even halfway checking the circuit boards for rare / expensive / interesting chips. |
|
Back to top
|
|
|
tjookum
Joined: May 25, 2010 Posts: 360 Location: Netherlands
Audio files: 26
|
Posted: Sat May 07, 2011 4:48 am Post subject:
|
|
|
stop making the rest of us feel jealous .
One tip, never trow a board away unless you either stripped it bare of are sure that all the leftover components are useless. I stripped my share of boards and I've trown away very usefull parts because I just didn't know what they were. _________________ There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.
Hunter S. Thompson
movies
noise |
|
Back to top
|
|
|
Psyingo
Joined: Jun 11, 2009 Posts: 248 Location: Canada
|
Posted: Sat May 07, 2011 8:17 am Post subject:
|
|
|
tjookum wrote: | stop making the rest of us feel jealous .
One tip, never trow a board away unless you either stripped it bare of are sure that all the leftover components are useless. I stripped my share of boards and I've trown away very usefull parts because I just didn't know what they were. |
and the addition to that tip:
always check the chip numbers for datasheets while you pillage those boards.
http://www.datasheetarchive.com is your friend. |
|
Back to top
|
|
|
Glitch-Militia
Joined: Apr 25, 2011 Posts: 25 Location: Europe
|
Posted: Sun May 08, 2011 7:05 am Post subject:
|
|
|
Psyingo wrote: |
and the addition to that tip:
always check the chip numbers for datasheets while you pillage those boards.
http://www.datasheetarchive.com is your friend. |
Uhmm yeah that's what I'm doing. No need stating the obvious.
I also forgot the 3-400 DPDT's |
|
Back to top
|
|
|
-minus-
Joined: Oct 26, 2008 Posts: 787
Audio files: 13
|
Posted: Sun May 08, 2011 1:55 pm Post subject:
|
|
|
Glitch-Militia wrote: |
Uhmm yeah that's what I'm doing. No need stating the obvious.
I also forgot the 3-400 DPDT's |
Wow! With all those pots you could build a pretty huge mixer! |
|
Back to top
|
|
|
|