PedalPCB 1981 inventions DRV clone

This is a build of the PedalPCB Informant, it’s a clone of the 1981 Inventions DRV, which is a great sounding evolution of the ProCo Sound Rat. I’d call this a beginner to intermediate level project. The PCB is easy to work with and well laid out with plenty of room to work. The only thing that moves this up from a beginner project is the charge pump. It’s not hard to work with but you do have be careful as these can be blown up easily, there are a few different parts to choose from, and depending on the part number you may need to solder the jumper on the back of the board.

This shares a lot with the Klon but goes further in the drive/distortion range. The DRV and Klon use a charge pump to run on 18 volts. This gives the pedal greater headroom. It also makes it a poor candidate for batteries. They both use a similar clipping architecture with diodes to ground after the op-amp, like a lot of other designs. While the diode arrangement and charge pump are similar the sounds are pretty far apart. The Klon has a deeper mid focused growl and and DRV has tighter sharper mid chunk. It’s the difference between Tom Waits and David Lee Roth.

I used a black powder coated 125B enclosure. I milled the logo and labels into the enclosure with a desktop mill.

Assembly

The PCB is east to assemble and well laid out with plenty of room to work. The pots and LED are mounted to the board which makes for little work wiring and mounts the PCB in the enclosure.

I assembled everything in the enclosure without soldering, fitted the washers and nuts on the pots and bent to LED into position, then soldered the leads on everything.

The docs provide a drilling diagram for a 125B box with the jacks at the top which is a popular arrangement and works well.

Wiring

The PCB makes the off board wiring organized and easy to implement. There are two options to choose either buffered bypass or true bypass. The true bypass option removes the effect entirely from the signal chain and the signal passes from the input to the output through a wire. In the buffered mode one of the op-amps is used as a unity gain buffer when the effect is bypassed. I chose the buffered arrangement for this build which is how the original 1981 DRV works.

Cost

Parts for this project are easy to get and common. The thing of note is the charge pump which are about $2 and can be blown if they get shorted. I’ve burned up a few in the past. It’s this charge pump the boosts the 9 volt power supply up to 18 volts.

Running at 18 volts you’ll want to use 1/4 watt resistors and make sure the caps are rated 25 volts or height.

The other parts are pretty common TL072 op-amps and mostly 10k and 100k resistors. You might have all the parts left over from a previous project!

How Does it Sound?

It sounds like ROCK! This is a total ‘80s rock machine. In some ways it has some of the character of a Klon. But the Klon has a deeper/darker mid range and goes from almost clean to heavy overdrive. The Informant/DRV goes a from distorted to really distorted with with brighter mid range and tighter bass.

Here is a video demo: