Joe Britt's Enhanced LM-1 Drum Machine

Joe and Roger

I've recently met a new friend named Joe Britt, founder and CEO of a tech company here in Silicon Valley called Afero, and designer of some significant tech products over the years.

Lucky for me, Joe also has a personal interest in my old drum machines. A few years ago, a friend of his gave him (!) one of my old LM1 drum machines. He enjoyed playing with it, but he wished it had a few extra features like loading alternate sounds from files, and pitch and pan knobs on the front panel.

So he decided to make his own enhanced LM1. He searched the web and found some incomplete old schematics, filled in the gaps by reverse-engineering the boards, then redesigned and replaced all of the circuit boards to include his enhancements. Note in the photo above that his redesigned boards are about half the size of the original boards, and are purple! Prince would have loved that.

Here are photos of Joe's enhanced LM-1:

In his design, he remained faithful to the original hardware circuit, but 1) replaced the original sound ROMs with RAM chips, then 2) added a Teensy CPU board and software that could take control of the original circuit and computer when he wanted to load different sounds into the sound RAMs. He also replaced the original front panel 3-position pan switches with full-rotation pots--with illuminated shafts-- that could act as either full pans or pitch controls.

Here's a video Joe made, showing it loading sounds and using the pitch/pan pots:

Here's what Joe wrote to me about his project:

"For me, as a kid growing up in the 80s, the sound of the LM-1 was the sound of my people. The Human League, Heaven 17, Yazoo, Gary Numan-- so many of my favorite bands from that time built their sound around the LM-1. And of course Prince, who used the LM-1 to create the "Minneapolis Sound." So I started with a very emotional attachment to work created with the LM-1.

I love technology, and I love products, and I really love taking things apart to understand how they work. Once I understood how influential the LM-1 was, I wanted to understand what was inside. But there were so few LM-1s made, and I could find relatively little detailed information about them online.

I finally found those nth-generation schematics, and could at least understand the hardware architecture. (But it wasn't clear enough to build a clone.) The schematics did reveal some very surprising design details. The first was that there was a DAC per voice! I did not expect that. And then -- the sample rate clocks were from 555 timers, holy smokes! Then I realized that the Z-80 wasn't using interrupts (whoa!), and that there was something special about how the Hi Hat sounds are made.

The LM-1 was just this box of technical surprises, and all together they created something that was just magical. The samples are digital, but the playback clocks and the tempo clock are generated by non-digital sources (the 555 timers, and an analog VCO for the tempo clock). So it's mostly digital, but with a very non-digital "heart."

Couple all of that with your very clever Shuffle algorithm, and some happy accidents like the bit of delay at the front of the Snare sample, and out comes the magic. Reverse-engineering magic is very rewarding.

From user groups online, I knew that there was a rabid following around the LM-1. They are coveted objects. They go for very high prices now, partially because there are so few of them.

Then, in 2021, that stroke of luck happened, and an old friend cleaning out a storage room asked if I would like to have an LM-1! I picked it up, and it had several problems that needed addressing, but now I could fill in the gaps from those schematics.

I think other folks had talked about building a clone of the LM-1 for a while, but it just hadn't happened. When I got started on the project, I was worried -- I thought, "I better hurry up and do this before someone else does!"

Then as I got into it, I calmed down and thought, "No, this is insane -- I'm glad I'm doing it, and I doubt anyone else is crazy enough to do this."  I felt strongly that the best way to really make it sound and feel like an LM-1 is to really make it work like an LM-1. And that meant reverse-engineering hundreds of design details, and re-implementing them. And doing it in a way that preserved the magic, but added on some modern features like MIDI and downloadable samples.

The urge for mission creep was constant. I think I did a pretty good job keeping it under control, and am super happy with how it turned out.

When I found out you live in Los Altos, literally 5 minutes from my house, I just felt like the universe was telling me something, Roger. I'm very grateful that I was able to find a connection to you through [our mutual friend] Pat, and very much enjoy and appreciate our conversations and hanging out!"

Joe is still improving his creation, adding a small LCD screen, MIDI, USB, a new metal chassis and more. Here are pics he just sent me of the new redesign. Notice the small LCD screen next to the MENU button, Pan and Pitch controls above the mixer, and the name "Luma 1", named after his dog Luma, the resident canine mascot at Afero:

Joe told me that he enjoyed the process of this project, sitting on his sofa with a glass of wine and his laptop, working on the design, schematics, circuit boards and software. What a gift it is that something I created years ago can inspire such a talented and accomplished guy as Joe is. Thanks, Joe.

One last question: neither Joe nor I have one of the old LM1 data cassettes containing the original preset drumbeats, and he couldn't find one anywhere on the web. Does anyone have one of these, or preferrably an audio recording of the data signal that was on the original data tape? If you do, please email me (Roger).

Update August 30, 2023: Two highly skilled engineer friends of Joe's (and now friends of mine) named Andrei Kudryavtsev and Devin Riley will be making a small number of Luma1 units for sale. Here's an Instagram page about their project.