Swap 250k trimmer for 250k pot? - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 20th June 2012, 12:53 AM   #1
diyAudio Member
 
nonsuchpro's Avatar
 
Join Date: Sep 2011
Location: Bowie, MD
Default Swap 250k trimmer for 250k pot?

Hey all.
Not sure if this is the right place to ask, please move it if so.
I am building this Velleman preamp kit and want to swap out the 250k trimmer for a 250k pot and knob. My question is which type do I need... audio taper or linear taper?

Velleman nv

Thanks in advance!
__________________
My Studio
  Reply With Quote
Old 20th June 2012, 07:31 AM   #2
diyAudio Member
 
Groundloops's Avatar
 
Join Date: May 2004
Location: fubar Germany.
Get a linear one.
  Reply With Quote
Old 20th June 2012, 10:50 AM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
I can't see a schematic.
But I guess at two alternatives.
1.) if you want to use the pot as a volume control, then use an audio taper pot, also called a log law pot.
2.) if you want to use the pot as a sensitivity control, then use a linear pot. That way you can set to 50% or 10% by estimating the rotation angle as a proportion of the total adjustment angle (usually about 270degrees).
__________________
regards Andrew T.
  Reply With Quote
Old 20th June 2012, 05:41 PM   #4
diyAudio Member
 
nonsuchpro's Avatar
 
Join Date: Sep 2011
Location: Bowie, MD
Thanks guys! I will go with linear
__________________
My Studio
  Reply With Quote
Old 20th June 2012, 08:13 PM   #5
diyAudio Member
 
nonsuchpro's Avatar
 
Join Date: Sep 2011
Location: Bowie, MD
One more quick question... I have a 1M pot brand new I never used from another project. What would happen if I used that instead of 250k?

Here are the schematics:

Click the image to open in full size.
__________________
My Studio
  Reply With Quote
Old 21st June 2012, 07:01 PM   #6
macboy is offline macboy  Canada
diyAudio Member
 
Join Date: Oct 2003
Location: Ottawa, Canada
You could put the 1 Mohm pot in parallel with a 330 kohm resistor. This will create a ~250 kohm pot with a non-linear taper. The non-linear taper could be a good thing since this is a gain control. It will provide a more natural feel when adjusting than a simple linear pot.
  Reply With Quote
Old 22nd June 2012, 09:29 AM   #7
diyAudio Member
 
nonsuchpro's Avatar
 
Join Date: Sep 2011
Location: Bowie, MD
Quote:
Originally Posted by macboy View Post
You could put the 1 Mohm pot in parallel with a 330 kohm resistor. This will create a ~250 kohm pot with a non-linear taper. The non-linear taper could be a good thing since this is a gain control. It will provide a more natural feel when adjusting than a simple linear pot.
Thanks
__________________
My Studio
  Reply With Quote
Old 22nd June 2012, 09:58 PM   #8
diyAudio Member
 
Speedskater's Avatar
 
Join Date: Sep 2002
Location: Lakewood, Ohio
A pot in the feedback loop of an op-amp will be very sensitive to lead wire length. Try to keep the pot's wires as short as possible.
__________________
Kevin
  Reply With Quote
Old 24th June 2012, 06:41 AM   #9
diyAudio Member
 
nonsuchpro's Avatar
 
Join Date: Sep 2011
Location: Bowie, MD
Quote:
Originally Posted by Speedskater View Post
A pot in the feedback loop of an op-amp will be very sensitive to lead wire length. Try to keep the pot's wires as short as possible.
2-3"s is that too much?
__________________
My Studio
  Reply With Quote
Old 24th June 2012, 07:30 AM   #10
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Yes.
__________________
regards Andrew T.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
WTB Alps LINEAR TAPER 250k MOTORIZED Potentiometer... ga1960z Swap Meet 1 28th December 2010 03:26 PM
Source for a 250K, 2gang(stereo) pot? Mosquito Parts 11 10th March 2010 11:23 AM
WTB: ALPS RK27 250K Potentiometer mrdon Swap Meet 14 6th August 2008 11:17 AM
Alps 250k in a Pas-3 Question Pyre Tubes / Valves 2 20th September 2006 08:24 PM
100K, 250K or 500K POT? D_GR8_1 Chip Amps 5 26th November 2004 06:46 AM


New To Site? Need Help?

All times are GMT. The time now is 02:43 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2