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TBX tone control

7/24/1997 4:26 PM
Jim Gross
TBX tone control
Hi! Was wondering if someone can tell me how a TBX tone control works. Is this an active control?? Anyone have a schemetic??  
Thanks, Jim.
7/25/1997 5:52 AM
Dave Harris

It is passive. It uses a twin ganged pot with different values for each half and a center notch. Center to anticlockwise works as normal tone control. Center to clockwise increases the highs. I am not sure of component values. I have a schematic at home I can post up on Monday.
7/28/1997 6:13 AM
Dave Harris

The TBX is a concentric 1M lin / 250k log pot.  
Tone pot selector SW to wiper of pot A.  
ACW of pot A to wiper of pot B.  
ACW of pot A to ground via 82k resistor.  
CW of pot A no connection.  
ACW of pot B to ground via 0.022u capacitor.  
CW of pot B no connection.  
I think pot B is the 1M and pot A is the 250k but I canít tell from the drawing.  
Someone please correct me if I am wrong.
7/28/1997 10:32 AM
Jim Gross

Thanks Dave...  
I also found out that Fender sells a TBX tone control kit. P/N: 099-2052. Don't know the price yet.  
Thanks again, Jim.
7/29/1997 2:10 AM
Dave Harris

I think it was about 15 pounds in the UK  
9/12/1997 2:59 AM
Steve Ahola

The schematic for the TBX won't do you any good unless you have the special oem Fender control, but I thought I'd explain how it works.  
There is a center detent, which corresponds to a normal tone control set to 10. As you turn it down to 1, it acts just like a regular tone control.  
The neat trick is that as you turn it up from 5 to 10, it gradually removes the tone control from the circuit, so you get a much brighter and slightly louder sound from your pickups.  
A normal tone control is always in the circuit, even when set to 10 since some of the signal is being bled to ground through the 250K or 500K pot and the tone cap. With the TBX set to 10, the tone control is completely out of the circuit.  
To save a few bucks, you might want to check out your local guitar repair shop as they may have one laying around that they took out of someone's guitar.  
I forget what value tone cap Fender ships with the TBX because I usually put in the .015 Eric Clapton "Woman Tone" cap.  
The TBX works especially well in conjunction with a passive mid-cut or mid-boost/mid-cut control. I usually rewire my strats so that the middle pot is a passive midrange control using Dan Torres' designs. For humbuckers, I like to use a mid-cut control to clean up the sound a bit when desired. For single coil pickup, I like the Dan Torres advanced mid control which boosts the mids from 7 to 10 (for a dirtier sound) and cuts the mids from 5 down to 1. You do lose some of your output signal even with the control set to 5 or 6 so I'll usually wire it up to a push-pull pot to take it out of the circuit completely when I don't want to boost or cut mids.
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