The Dirt Doctor Overdrive (Barber Gain Changer SR)

[Brett]

The Dirt Doctor Overdrive

What is it...
Based on the Barber Gain Changer SR.

Modifications...
Minor changes from stock. I replaced the fixed resistors in the recovery stage with trim pots so Mids and Bass were adjustable instead of fixed.

Sounds
I've always loved the Gain Changer, Mr. David Barber did an outstanding job on designing the circuit and it's a classic for a reason. The gain range on this one covers a lot of ground, from light overdrive to a mild distortion.

Enclosure
Winked Silver 125B from Tayda. Tayda handled the UV printing as well (double white, gloss varnish).

 

[Synchrony Pedalworks]

This looks really great! I always like your designs. Why do you add a white layer? Does it add depth to the graphics?

 

[Brett]

Thanks, I appreciate it!

Why do you add a white layer?

I always add the double white because it helps separate colors in almost every circumstance. It’s not a depth thing, it’s just about color quality.

 

[KT88]

Wow! That is humbling.

 

[benny_profane]

Great job all around! The layouts of your recent pcbs look really nice. What can you tell us about the I/O daughterboard?

 

[Brett]

Thank you, @benny_profane!

What can you tell us about the I/O daughterboard?

This is a modified version of Chuck’s Basic Relay Bypass that accepts up to 24V, has a SW pad (for compatibility with other boards). Mostly SMD aside from the jacks, on-board CLR, and LED.

 

[kylewetton]

Thanks, I appreciate it!


I always add the double white because it helps separate colors in almost every circumstance. It’s not a depth thing, it’s just about color quality.

That’s true, but this is black, without the white is simulating a “multiply” blend mode. With black, you’re not multiplying any colour, so what difference would it make? Genuinely curious, have you tried no white layer underneath for black graphics like this?

 

[Brett]

Genuinely curious, have you tried no white layer underneath for black graphics like this?

I haven’t, but it’s because I’ve always done it this way and through experience, observation, and research, this is what works for me.

Most of the time, my enclosure designs include white or some color (not just black). Adding a white layer is the easiest way I’ve found to have colors render as accurately as possible and eliminate the biggest variable (enclosure color). It also helps “build” the UV print some so it stands out a little more.