AB type J pot

George Macdonald · Post by **George Macdonald** » 11 May 2009 3:10 pm

I have an unused Allen Bradley type J 500K pot from the late 70S. I bought it as a spare to use someday, but not realizing I had this, I have used Claristat and PEC pots [and also a Dunlop in one pedal]. On the bottom of the pot it does say MEXICO. Is it likely to be as good as the ones that don't say Mexico? George

Jack Stoner · Post by **Jack Stoner** » 11 May 2009 3:41 pm

If it is a true Allen Bradley it is, or if it's an early Allen Bradley after it was purchased by Clarostat then it's still a "good" one.

George Macdonald · Post by **George Macdonald** » 11 May 2009 4:01 pm

Thanks Jack, I put it in an old pedal made by Larry Petree the other day. It works, but it seams like the taper is different. It has all the same numbers on it as the original that lasted for 30 plus years but most of the volume comes on about 2/3s of the way through the travel. It's no big deal because the pedal is really just a keep sake from days gone by. I have a recent Goodrich as well as a Hilton.

Donny Hinson · Post by **Donny Hinson** » 12 May 2009 3:48 pm

"Type-J" refers to the high power (2-watt) hot molded, panel mount pots. The taper is indicated by the next to last letter (or sometimes last letter, in non-mil markings) in the part number. Pots with an "A", "D", "K", or "R" after the last digit are what you want (That's a log, or volume taper). Pots where the letter after the last digit is a "U", "S", "F", "Y", "M" or "C" are all linear tapers (usually used for tone controls in our application).

Pots are made to pretty close specs, so one that seems drastically different probably is different.

The pot number I always recommend is JAIN200P504AA

George Macdonald · Post by **George Macdonald** » 12 May 2009 4:31 pm

Donny, The number on this pot is: JAIN200P504AA

John Billings · Post by **John Billings** » 13 May 2009 6:46 am

Donny, are any of these any good?
AB
A-673224
TYPE J

AB
JAIN 056S504AA
500K OHM 9023
TYPE J
MEXICO

AB
8674211 8218
TYPE J
MEXICO

AB
JAIN 056S504AA
TYPE J
MEXICO

OHMITE
TYPE AB
CU5041
500K
JN

Donny Hinson · Post by **Donny Hinson** » 13 May 2009 4:20 pm

George: Yes, that is the pot I recommend. (I removed the extra "1" in the part number I listed

)

John: The second and fourth pots you listed, JAIN 056S504AA will work in most pedals. They're a "short shaft" model, but electrically they are the same. The last pot you listed, OHMITE TYPE AB CU5041, will work too, but probably won't last as long (It's a commercial grade, as opposed to a Mil-Spec model.)

John Billings · Post by **John Billings** » 13 May 2009 5:08 pm

Thanks Donny!

James Cann · Post by **James Cann** » 30 May 2014 9:40 am

OK, how about some sources? Who has them?

John Billings · Post by **John Billings** » 30 May 2014 12:00 pm

Try to find a local Hamfest.

Jack Stoner · Post by **Jack Stoner** » 31 May 2014 2:42 am

That particular pot wasn't used in much equipment. It is a specialized taper. I've been through many "military surplus" sales and have never came across this specific AB pot.

I went back over some old ARRL handbooks (I have one from the 60's) and that pot is not referenced anywhere in the ARRL manual or Ad's.