tonestack wiring

[shooter]

Seems about every build I somehow screw up the tone knobs.  I was hoping someone could help me.  I drew up the layout, attached.

For bass and mid, is it 1 to 2 or 2 to 3 for tying the wiper?
For treble is it 1 or 3 connecting the incoming cap?

Thanks for helping the helpless!

[sluckey]

You've drawn the classic Fender AB763 TMB stack so just follow this Fender layout. If you really want to connect the wiper to the end of the pot just put a jumper between wiper and unused lug. Look here...

     http://el34world.com/charts/Schematics/files/fender/Fender_twin_reverb_ab763_schem.pdf

[shooter]

that seems to be my hang-up (among other things:), to me the "unused" lug is the wiper in the schematic the outer 2 go places.  I guess the better way of asking is; Is zero ohms = minimum bass, med, n treble?

[Ed_Chambley]

that seems to be my hang-up (among other things:), to me the "unused" lug is the wiper in the schematic the outer 2 go places.  I guess the better way of asking is; Is zero ohms = minimum bass, med, n treble?

When measuring from lug 1 across lug 2 the wiper, counter clockwise reduces resistance when using Linear and Audio pots we use most of the time in guitar amps.  If nothing else is connected, then the pot will measure '0" if turned all the way counter clock and measure across 1 and 2.

Check out this link and you will get a lot of info on pots.  Short read.

http://www.geofex.com/article_folders/potsecrets/potscret.htm

[sluckey]

to me the "unused" lug is the wiper in the schematic the outer 2 go places.

The wiper is the part of the pot that makes it variable. If you only connect to the outer lugs you will simply have a fixed value resistor.

Is zero ohms = minimum bass, med, n treble?

yes

[TIMBO]

Hi guys, I think T posted this..............

[shooter]

Thanks all, I get pots, what I don't get is complex band pass, band trap, simple RC or LC, I can muddle thru but looking at the schematic, it's hard to think; "If I turn that pot to zero, is that actually increasing treble, bass or decreasing it".  I use the tone stack simulator for curve shapes, but didn't know if zero dial = zero ohms so I took an amp apart that had all the knobs working the right way, turned it upside down n backwards then I knew which side was what.  And it worked!!  I did save the links.

thanks again, I'm getting there, where dono

[eleventeen]

As one who typically wires from schematics, not layouts, I will say that that the layout dwg for a Fender tonestack is 20x more useful than the schematic--in terms of exactly what you're saying. Wondering which is the "low" terminal on the pot, which one is grounded, etc;


When I'm wiring, I don't like having to ponder the rotation of the pot or how high-pass filters work. The bad part is having to undo then redo nice clean wiring because you got the rotation of the pot wrong. I like to get it right the first time and anything I can use to further that aim is fair game.

[shooter]

Thanks, I have 3 amps out in the public with at least 1 pot backward, when they ask, I say; "it's my signature design, you won't find that on any other amp!"