T-Drive potentiometer taper and pot locations on PCB

[Anonymous]

Hi there, I am looking to build a T-Drive using your PCB, however I’m a bit confused regarding the correct potentiometer taper to use for the Bass control. The build doc says to use a linear B50k, however the original Timmie used a log taper as a ‘bass cut’ control.  I’ve put together a T-drive circuit on my breadboard, and a log pot does give a good sweep, in ‘bass cut’ mode. The T-Drive build doc indicates that the pot directions have been reversed for the Bass and Treble controls, so i guess that the T-Drive bass increases with clockwise turn of the knob.

This is what Paul G recommended on a popular forum: “That’s pretty close, but it doesn’t show what tapers to use for the pots.  The gain, bass, vol should be audio taper.  The treble is linear.  If you want to flip to the rotation of the tone controls use a reverse audio for the bass and switch the outside lugs of the Treble.  For several years now I’ve used a 25ka for the volume with an 18k resistor from input to wiper.  This alters the taper to put zero gain unity at 12 o’clock. ”

1st Question: Should used a reverse log C50k pot for the Bass to get a good control range?

2nd Question: I cant see the bass, treble, gain and volume pot locations on the PCB or in the build doc. Can you please update the build doc with the locations so that i can get my enclosure labelling correct?

Thanks

Dan

[Barry]

Hi Dan,

Re: I cant see the bass, treble, gain and volume pot locations on the PCB

The labeling for the Pots Controls are silk-screened on the other side of the PCB and are labeled appropriately.

Note: This also includes a #1 in the silk-screen to signify orientation at each location.

Re: I’m a bit confused regarding the correct potentiometer taper to use

You may absolutely and easily change the Taper to your liking.

This is our personal preference to make it feel more natural for most guitarists (a very common complaint). So when we finally jumped on the band wagon we decided to address those complaints. While we understand how the original circuit works it is not always intuitive to every guitar player and since we are not that concerned with cloning we will implement modifications if we see a positive gain. Please use whatever taper works best for you. If you prefer to hand wire the pot and change lugs 3 and 1 as you already mentioned that is perfectly fine.

Our version is by design and the way we like it to be clear so there is no “reader confusion”.

Maybe build two and have a few guitar players do a blind comparison. 😉

I hope that helps.

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