Center tapped pots?

[martingriffith]

I'm laying out some PCB's for Barry Porter's NetEq, (see my old site, net equaliser on http://www.wavefront.mcmail.com/scans.htm ).

I'm having trouble locating some 10K linear center tapped pots that are horizontally mounted. I've looked at the 388 modular system from http://potentiometer.com/pdf_library2.cfm?pdf=catalog388.pdf
and its seem that only vertically mounting pots are available, fig 27

Any other suppliers that dont have a MOQ of 100,000?

martin

 

[Guest]

Yep - Omeg
http://www.omeg.com/e16typ1.htm
Look at the LA16ECO model...
Last time I ordered from Omeg it was a min of 10 pieces..
They can do Centre Tapped or Not, lin or log - each of the pots comes in those options...
T

 

[Rob Flinn]

What you`r e after are pots with a centre detent. i.e a click that hold them in place around the central postion.

Centre tapped pots are something different. Not commonly available nowadays, they are pots with a connection in the middle of the trace that you can connect to. The only place I`ve seen them being used is at the input of the control amp of the Fairchild 670.

Sorry if I`m being a bit particular, but I am !!

 

[NewYorkDave]

I've seen Porter's EQ design. They're talking about actual center-tapped pots, not just center-detent.

One other place where a center-tapped pot can be found is in Baxandall's original design for the active bass-treble EQ. The treble control was center-tapped. Some later versions of the design took a shortcut and left out the center tap. And then, of course, there are numerous examples of tapped volume controls in old hi-fi circuits (for "loudness" compensation).

 

[chrissugar]

Dave is right, center-tapped is an electrical thing and center-detent is a mechanical thing. The two can go together but not necessarily in all cases.

chrissugar

 

[gyraf]

Centre tapped pots are used in Sontec/GML stuff also as cut/boost pot. This ensures effective band bypass in centre position. Not easy to find.

Jakob E.

 

[martingriffith]

[quote author="Rob Flinn"]What you`r e after are pots with a centre detent. i.e a click that hold them in place around the central postion.

Centre tapped pots are something different. Not commonly available nowadays, they are pots with a connection in the middle of the trace that you can connect to. The only place I`ve seen them being used is at the input of the control amp of the Fairchild 670.

Sorry if I`m being a bit particular, but I am !![/quote]

Nope I want center tapped pots, detents are an option

martin

 

[Rob Flinn]

I`m not sure that OMEG do centre tapped pots.

I know they do centre detent ones.

I guess the only way to find out for sure is email them.

 

[weiss]

i know i'm bumping an old thread here but i got trouble locating 10k lin center tapped pots for my build. any help would be really appreciated!

 

[Rob Flinn]

i know i'm bumping an old thread here but i got trouble locating 10k lin center tapped pots for my build. any help would be really appreciated!

You could perhaps try Blore Edwards.  They are up for making custom pots I believe.  Speak to brett Cryer the operations manager.

 

[weiss]

You could perhaps try Blore Edwards.  They are up for making custom pots I believe.  Speak to brett Cryer the operations manager.

thanks rob!
contacted him.

 

[weiss]

bump. Does someone know an alternative? Still not able to find 10k lin center tapped and detented potentiometers. blore ed only has center detent pots

 

[JohnRoberts]

bump. Does someone know an alternative? Still not able to find 10k lin center tapped and detented potentiometers. blore ed only has center detent pots

These are generally not widely available in small quantity.

In many cases you can get away with standard linear taper pots.

Detents and center tapped pots are different animals. Center-tapped, an extra contact mid pot was historically popular for automatic loudness compensation... (bass boost at low volume settings). A more modern application for center tapped pots is back grounding boost/cut EQ pots at mid position to insure flat transfer function when set flat.

Center detents are more of a cosmetic issue to infer precision that may not exist.

I used to suggest buying similar parts from the service department of manufacturers still using them. These days with so much large scale manufacturing performed overseas service parts are an old school luxury harder for modern manufacturers to support.

Have you tried the circuit with a standard linear part?

JR 

 

[RuudNL]

I remember that some old Philips tube amplifiers used center tapped pots.
The output of for example the microphone preamp was conncted to one side of the carbon track, and the radio or phono source was connected to the other side. The center was grounded.
By turning the knob left or right, you could select the source you wanted to hear.

 

[JohnRoberts]

I remember that some old Philips tube amplifiers used center tapped pots.
The output of for example the microphone preamp was conncted to one side of the carbon track, and the radio or phono source was connected to the other side. The center was grounded.
By turning the knob left or right, you could select the source you wanted to hear.

I think I vaguely recall an old tascam mixer that did something similar.

JR

 

[user 37518]

What about this: https://www.mouser.mx/datasheet/2/54/ptvptt-778065.pdf

 

[gyraf]

bump. Does someone know an alternative

Are you sure you need them? for what?

 

[peterc]

They can be DIYed.

https://sites.google.com/site/chosenaudioproducts/tuxedoamp/tappedpot

There is also another example of this somewhere out on te Interwebs, but I could not find it.

 

[JohnRoberts]

What about this: https://www.mouser.mx/datasheet/2/54/ptvptt-778065.pdf

ding ding ding, we have a winner...

JR

 

[analogguru]

Behringer sells center tapped pots, unfortunately with a value of 50k lin only..... in their parametric EQ's.... time to buy used Behringer's....