In terms of circuitry, the TB-303 is quite simple: a single sawtooth/square wave oscillator, which runs into an envelope-modulated low-pass filter. The onboard sequencer allows for pretty intuitive programming of notes and slides, all of which amounts to a squelching, liquified, wonderfully overdriven sound, which itself became part and parcel of the acid house genre and beyond.

While the 303 has been reproduced in a multitude of forms and formats —  analogue and digital, hardware and software — the original still regularly fetches several thousands of dollars on the secondhand market. To celebrate its legacy, we’ve put together some of our favorite 303 samples from Sounds.com in the form of the Acid Sounds collection, and spoke to some of our esteemed suppliers about their love of the timeless machine.

“I aimed to recreate the famous ‘squelch’ of the 303 in as much detail as I could,” says Micah Frank at Puremagnetic, of his pack TeeBee Loops. Frank’s primary objective was to capture the 303’s infamous filter, with sawtooth and square waveforms running through it, in a unique way — a challenge, certainly, as 303 sample libraries abound. Frank wanted to make sure his sounds stood out, both terms of authenticity and sound quality.

“The production process for capturing such a nuanced instrument was quite complex,” he explains. Frank used the technique of “permutative sampling” — a very granular approach to sampling, wherein each change between controls is recorded systematically, designed to capture every possible combination of all control positions, and which results in thousands of samples per waveform/filter change. The sounds were recorded with these permutations, and later programmed as both a software instrument and loop library, the latter which is available on Sounds.com.

Beyond the standard techno and house applications, Frank says these sounds can in fact be used much more broadly. “It sounds great in pop music and EDM, [and] it can even be layered into rock for some crossover flavors,” he says. “Additionally, you can use the sounds to beef up a kick drum. Simply chop up a TeeBee [loop], for instance, and layer single notes behind your drum for some extra oomph. Or use an expander to side chain trigger the TeeBee phrase with your kick drum. You can get quite creative!”

For its TB-303 pack, Soundtrack Loops was focused on trying to get “that raw, underground warehouse techno sound,” and to offer a mix of the classic Chicago sound (read: Acid Trax), along with the harder-hitting 90s rave sound, popularized by the likes of Richie Hawtin.

“The 303 is a synth with a very unique sound, mostly due to the sequencing style and note glide — not to mention an insanely resonant filter, that would really cut through the mix,” they tell us. “This particular sound started a whole genre — just like Skrillex’s growling, heavy synth basses defined the new dubstep, for example.” Soundtrack Loops also points out that the TB-303 is easy to play, which made it inspirational for a generation of electronic music pioneers. “It’s really inspiring, and doesn’t take much skill to pop a few steps in, add some glide, and tweak that cutoff knob. This made it way accessible to a lot of dance music producers who had very little traditional music training.”

In addition to the original TB-303, Soundtrack Loops also sampled the rather rare, 303-influenced Future Retro Revolution FR-777 synthesizer, which they borrowed from a friend expressly for this purpose. “The two synths are very close in sound at times, but the FR-777 isn’t a clone of the 303. It was more-or-less inspired by the 303, [but] the 777 can achieve a large range of sounds because of additional features like [frequency modulation] and different filter types, to name a couple.” They also recommend checking out their X0X Synths release. “These two packs should give you more than enough material to write several acid house/acid techno bangers!”

Finally, sample purveyor Smokey Loops tells us that the 303 sound is one of their favorites because it reflects “an acid sound that’s part of our musical culture.” During the processing of the sounds for its 303 Acid Sounds pack, a great deal of attention was paid to the use of the TB-303’s sequencer, lowpass, resonance, and accent filters. To create the pack’s vocal samples, text-to-speech software was run through the filter, and processed with plug-ins like Camel Crusher, Ozone 8, and Vengeance. All of this, they tell us, to the ends of creating a “modern acid sound.”