rangemaster tonepad question

[freak scene]

i want to build a range master off of the tonepad layout, but here is my concern.  the layout on tonepad is a pnp layout that has negative ground.  i have a couple of npn transistors i want to use, i have heard that if you flip the electrolytics you can get by, but wouldnt this make it positive ground?  i really want to keep it negative ground so that i can use my power supply.

also on the military oc140's is the red dot the collector?  ive assumed this but was not positive.

[hairyandy]

i want to build a range master off of the tonepad layout, but here is my concern.  the layout on tonepad is a pnp layout that has negative ground.  i have a couple of npn transistors i want to use, i have heard that if you flip the electrolytics you can get by, but wouldnt this make it positive ground?  i really want to keep it negative ground so that i can use my power supply.

also on the military oc140's is the red dot the collector?  ive assumed this but was not positive.

Try using Dragonfly's NPN Rangemaster layout (http://aronnelson.com/gallery/album18/DALLAS_RANGEMASTER_NPN_VERO)

This layout is negative ground and will allow you to use the OC140.  And yes, the red dot is the collector.  These transistors sound great and this pedal will sound really good with it.  If you don't have any stripboard, just use the same layout on perfboard (like Velleman's pad-per-hole boards) and then connect the "strips" or "busses" on the solder side with the discarded clipped leads from your resistors and caps.  I've built many this way and it's really pretty easy to do.  Just be sure to solder each component point to the strip that you use and use your DMM to check for continuity.

Also, be sure to socket your transistor so you don't fry it!  If you don't have a socket, use an alligator clip as a heat sink to keep excessive heat from destroying the tranny....

Good luck and post back with any problems.  The Rangemaster circuit is so simple it's almost a shame to use a PCB, no offense Tonepad or J.D.! 

[vanhansen]

I've got some OC140's and the red dot is the emittor, the bag is labelled that way.  When I build my RM, I took the schematic from the Schematics page and used the same parts, just flipped the electrolytic caps around and used an NPN transistor.  That's it.

[hairyandy]

I've got some OC140's and the red dot is the emittor, the bag is labelled that way.  When I build my RM, I took the schematic from the Schematics page and used the same parts, just flipped the electrolytic caps around and used an NPN transistor.  That's it.

The red dot on your OC140s is the emmitter?  Maybe I'm remembering wrong then?  The way I always figure it out is to stick it in my DMM's hfe tester and find out which way it works.  Also, if you socket the tranny you can just swap it around if it's wrong.

[vanhansen]

Yup.  I got a bag from MartyMart around Christmas.  It's written on the label, by him I think.  I need a new DMM that does more.  Right now it's either knowing the pinout or figuring it out, and using the nice printouts from AMZ and stuff.

[freak scene]

so the red dot is the emitter?  hopefully i didnt fry the one i had in there.  i am using the dragonfly vero layout on perfboard, but i have some vero on its way, so i may end up re doing it so its neater.

and sockets are the best thing ever invented.

and any recommendations on a good dmm with hfe?  i am currently using one of the cheap o ge ones that you can get at wal mart.