Looking for something to challenge your building skills? The Pro Collection is a line of DIY projects designed for the expert pedal-builder who wants something a little out of the ordinary. They are designed like professional pedals with specific assembly techniques and components used, and they also come with artwork files if you want to get the enclosures professionally screenprinted.

Lab Series L5 Preamp

Lab Series L5 Preamp PedalThe Lab Series was a line of solid-state guitar and bass amplifiers designed by Moog in the late 1970s. They are the product of a few years of research into the sonic characteristics of tube amplifiers on top of Moog’s already-vast expertise in analog audio design.

This project is a replica of the preamp section of the L5 guitar amp, which is where all of the unique character comes from in the amp. In addition to some really interesting filter design work, it also features a unique OTA-based overdrive which has never been used outside of these amps to my knowledge. The result is an effect that is the very definition of “amp-like”… because it is one.

This pedal can be used as a deluxe overdrive effect if the levels are kept low. But it’s more than capable of driving a power amp by itself, and that’s going to be where it shines.

l5pre_pcb_populatedNow for the fun part: Twelve knobs, 80 resistors and 50 capacitors. It’s designed for a 1790-sized enclosure—think Electro-Harmonix “XO” series. It’s not a difficult or finicky circuit, but it’s going to be a lot of soldering and you have to be very careful because one resistor of the wrong value could take a very long time to debug. If you’re willing to put in the time, though, all the information is provided for you to end up with something that looks just like the photo above.

I’ve made a spreadsheet of the parts so you can very easily order most of what you need from Mouser. The remaining items can be obtained from Small Bear or Mammoth Electronics in the United States or any of the major European part stores. There are no “unobtainium” or mojo NOS parts to hunt down.

The screenprint artwork for the above pedal is available for download and can be sent directly to Pedal Parts Plus or modified to taste using Adobe Illustrator. (Note that the text is in black so it can be seen in the PDF. If you’d like to print it as white on a dark enclosure, just tell them to change it to white during the printing process and they can take care of it.)

Logo nameplates

I also came up with something extra for this project since it’s such a special one to me:


These are ultra-high-resolution aluminum nameplates featuring the original Lab Series logo. They’re $5.00 each, and they come with the screws and nuts for mounting to the enclosure (one black screw and one silver screw to match the colors). The screenprint artwork has been designed with the nameplate in mind, and the drill marks are built into the artwork.

Next up: Boss Dimension C

The next release in the Pro Collection will be the Boss DC-2 Dimension C. This circuit is legendary for two reasons: first, it’s considered by many to be the best analog chorus ever made, favored by guitarists and keyboard players alike; and second, it’s enormously complicated—probably the most densely-packed PCB of any commercial pedal. Because of this, it’s never had a proper DIY clone PCB.

All that will change in about two months! This is going to be a fun one: I started out with the design rules that 1) it had to be no bigger than the original Boss unit, 2) it had to have all the same functions as the original, 3) it couldn’t use any SMD, and 4) it had to use all flat 1/4W resistors instead of the stand-up 1/8Ws of the original. It also supports either the original MN3207 BBD or the higher-headroom MN3007, and it has two different choices for the bypass method.

Stay tuned!