Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

 #84270  by tcsned
 Thu Jul 29, 2010 1:43 pm
aoguitars wrote:Way to come full circle, too, to the original post...Dan Erlewine is the main dude at Stew Mac.
and worked with Don MacRostie who built the mandolin that the mando player in my bluegrass band uses - Red Diamond. Nice instrument.
 #93225  by TI4-1009
 Fri Feb 04, 2011 10:51 am
Yeah, the 500/250 modpot has me lookin too. I'm guessing that this is not a switchable (push/pull, etc) pot, just a double pot on the same shaft, turning the knob turns both pots? 250 for the neck single coil, 500 for the bridge humbucker? Where is a good source for top quality? Thanks!
 #93304  by TI4-1009
 Mon Feb 07, 2011 7:09 am
Thanks Jon! Don't know how I missed that?
 #93305  by waldo041
 Mon Feb 07, 2011 7:54 am
yes, that could serve the purpose, but it is a concentric pot with 2 shafts requiring 2 knobs. it also is an audio/log pot. probably one of the only options besides finding a 250k/250k dual like wolf. some have, including myself, have just made our own 250k/500k's by disassembling a 250k/250k and a 500k/500k linears and reassembling the bottom wafers on the other pot.

 #93306  by Jon S.
 Mon Feb 07, 2011 8:07 am
My link to a source for the Allparts knob is intended for those among us who are not pro electrical engineers (or at least not electrically totally lame like me). But I have a better idea. All in favor of Waldo building a bunch extra and listing 'em for sale on his web site, say aye. (You can put me down for an advance order. ;) )
 #93308  by TI4-1009
 Mon Feb 07, 2011 10:29 am
I knew that was too easy. I had Googled all combinations of "Allen Bradley AB linear Modpot 500 250" and never could hit it.

I second Jon's suggestion- make me one Waldo and I'll get it alongwith the TPC-1 I need?!

For the electronically adventuresome- following Waldo's lead I found a site that has both 500 and 250 linear duals: ... =10&page=1
 #98659  by TI4-1009
 Fri May 27, 2011 11:35 am
Alpha Dual Potentiometers - Linear Taper, 8mm Bushing
24 mm carbon composition
300° rotation
1/2 watt
1/4" diameter solid shaft
Solder lugs
500 VDC rating

I found them here:

They have them in 250 and 500k. Dual, linear, single shaft, the only drawback is the bushing is 8 mm as opposed to the usual 3/8", but as long as you're starting from scratch you can drill the hole you want. Hopefully they are easy to open up and swap the resistor wafer.