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Pot-Pin-Out-Please?

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tblo163

New Member
I've found an interesting potentiometer in my box of bits,it has 10 pins.a row of two(which is the switch terminals) & two rows of 4 pins,(twin gang pot).I'm obviously fully familiar with the normal 3pin layout,but I have not a clue what the 4 pin pot is used for,it looks to be very well made(not a cheapy)it is marked 708r 50K DX2.Anyone know the pin outs for this pot?
Thanks in advance Terry
 

Sceadwian

Banned
Pictures needed. Descriptions for that kind of devices are useless because they are often custom built for the application.
 

crutschow

Well-Known Member
Most Helpful Member
It's likely a stereo audio volume pot with a 4th terminal loudness tap on the pots between the two fixed end terminals. By connecting an appropriate RC network, it can be used to give a loudness function (increased bass and treble at low listening level) to compensate for the ears reduced sensitivity to the high and low frequencies at low sound levels (see http://www.angelfire.com/electronic/funwithtubes/Amp-Volume.html)
 

tblo163

New Member
Reply to your post

Thanks for the info,Ive looked at the link,and will study it in detail.I've tested the pot,& allthough it's marked 50K, I get 44k between the fixed pins,Assuming the pins are #1,2.3&4, 1&3being the fixed pins,2 wiper,& 4 the out side pin.then the readings are-1&3=44k. 1&40k, 3&4=4k,(these are the fixed settings)between the wiper and fixed pins resistance varies as normal.Between the wiper and pin4, turned fully anti clockwise,it starts at 4k,then turning clocwise,it reduces to 0 at half way,& then increases to 40k
for the rest of the turn.(Now I'm really confused)Anyway I'll study the link and see if I can use it.Iwant to install tone controls to my amp,and have got the suitable pots,so if I can find a diagram ,I might go this way.Your advice has allways been good,so I will follow it up.The resolution of the PDF is not too good,but if you zoom OUT it looks better,
regards-Terry.
 

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crutschow

Well-Known Member
Most Helpful Member
Apparently pin 4 is connected about 4k from one end of the pot resistance element. That's why the resistance between it and the wiper goes to zero at 4k from one end and 40k from the other end (total pot resistance of 44k).

Make sense?

Incidentally, this is for a volume control not a tone control, although it does affect the tone as you change the volume to generate the loudness function.
 

tblo163

New Member
Yes.it's starting to register,I'll see if I can find a way to connect it up,and give it a try.
I've not seen any diagrams using a 4 pin pot.Thanks again. Terry
 
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