Wierd ALPS motorised Pot - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 4th May 2007, 02:02 AM   #1
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
Default Wierd ALPS motorised Pot

I pulled this thing out of a Pioneer XR-P250 stereo system that the neighbour threw away when the CD player quit. I was planning to use it in my amp and figured it would just be an ALPS motorised pot (it looks similar to an RK168)

However when I measured the pins, it didn't correspond to any of the dual pots ALPS seem to have data on. It also had some wierd connections in the original Pioneer. Here is a rough idea of how one channel was connected:

Click the image to open in full size.

I measured the following:

Between 7 and 3 = 84K
Between 8 and 3 = 42K
Between 8 and 7 = 42K
Between 2 and 8 = 42K->0->42K (turning CW)
Between 2 and 7 = 84K->0 (turning CW)
Between 2 and 3 = 0->84K (turning CW)

Obviously I could just use the normal connections (2, 3 and 7) but 84K is a little high for a volume pot. I'm also intrigued as to how this arrangement is supposed to work. The pot was mounted on an individual board containing the pot, H-bridge IC, preamp based around a 4558, and muting transistors.

edit: The code sticker on the pot says
ACX7003-A
506t
  Reply With Quote
Old 4th May 2007, 02:15 AM   #2
diyAudio Member
 
Sonusthree's Avatar
 
Join Date: Dec 2005
Location: Sussex, UK
Does it have some kind of 'loudness' control built in for low volumes?
Just a guess
  Reply With Quote
Old 4th May 2007, 02:29 AM   #3
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
That was what I was thinking.. but 42K-0-42K thing coupled with what appears to be a filter makes me think its some kind of trick to keep the impedance constant across the whole range of the control.
  Reply With Quote
Old 4th May 2007, 04:47 AM   #4
diyAudio Member
 
Join Date: Jul 2003
Location: Dona paula, Goa
It has seven connections...
then it is a dual stereo pot with loudness connection.
What confuses is the ground connection and is shorted internally for both the pots.

Gajanan Phadte
Attached Images
File Type: jpg pot.jpg (6.3 KB, 95 views)
  Reply With Quote
Old 4th May 2007, 05:25 AM   #5
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
Cool, I get it now.

Just wondering how best to use this. Obviously, I don't want a "loudness" circuit in my hi-fi amp altering the sound!

looking at this helps. Hm, according to tests, this is a linear pot.
  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
-Possible Trade- 2ch motorised alps pot for 4ch matt09 Swap Meet 1 28th June 2009 12:19 AM
motorised faders fanjita Parts 2 12th December 2006 04:19 PM
Motorised pot hugobors Parts 4 3rd February 2006 12:15 AM
FS: Alps RK27 motorised volume pot with remote controller PCB ready to fit in amp rabbitz Swap Meet 3 8th September 2004 03:09 PM
motorised potentiometer trancy Parts 0 11th March 2004 06:03 AM


New To Site? Need Help?

All times are GMT. The time now is 11:14 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