ALM Busy Circuits Pip Slope Mk II (2018–)

A 4HP module that is tiny, precise, and can set off entire sequences with a single trigger.

Overview

The Pip Slope Mk II has four knobs, a few jacks, and a quiet front panel. There are no flashing lights and no 20-page manual. Behind that panel is a full-function envelope generator, not just another AD/ASR module to slap in a skiff to save space. With the flip of a switch and a twist of a knob, it goes from a snappy percussion shaper to a glacial, looping LFO. It does all of that in 4HP.

At its core, the Pip Slope Mk II is a dual-mode envelope generator: Attack/Decay for percussive hits, Attack/Sustain/Release for the classic synth envelope contour. It also works as a function generator, a looping LFO, a burst modulator, or a rhythmic trigger sequencer. The shape control morphs the envelope slope from logarithmic (sharp attack, long tail) to linear (predictable rise/fall) to exponential (slow start, fast snap). It isn't a coarse switch. It's a continuous, voltage-controllable parameter, so you can change the character of an envelope in real time. Voltage control over both attack and decay times comes on top of that.

The Mk II improves on the original in refinement. It keeps the same 4HP footprint and adds selectable 5V or 8V maximum envelope output (handy for driving VCAs or modulating other modules that prefer higher CV), increased output resolution for smoother curves, and finer control over fast envelope times, so no more mushy sub-millisecond attacks. The "End of Cycle" trigger output spits out a precise pulse when the envelope completes, whether it's a one-shot or a loop. That's useful for cascading sequences, triggering fills, or clocking other modulators in sync. It loops, too, in three modes. Regular loop gives steady LFO action. Decreasing amplitude gives echo-style decays. Decreasing time gives a "bouncing ball" effect where each repetition gets quicker until it fizzles out.

Specifications

Manufacturer	ALM Busy Circuits
Model	Pip Slope Mk II
Model Number	ALM028
Production Years	2018–
Module Type	Envelope Generator / Function Generator
HP Size	4
Depth	38mm
Power Supply	+12V, -12V
+12V Current Draw	30mA
-12V Current Draw	10mA
Envelope Modes	Attack/Decay (AD), Attack/Sustain/Release (ASR)
Envelope Time Range	Approx. 1ms to 7 minutes per stage
Shape Control	Morphs between logarithmic, linear, and exponential slopes
Voltage Control	Attack and Decay times (CV inputs with attenuators)
Trigger Inputs	Gate input (for ASR), Trigger input (for AD)
Outputs	Envelope output, End of Cycle trigger output
Max Envelope Level	Selectable 5V or 8V
Loop Modes	Regular loop, decreasing amplitude, decreasing time
Reverse Polarity Protection	Yes
Country of Origin	United Kingdom

Key Features

Shape Morphing: The Secret Weapon

Most envelope generators lock you into a fixed curve: exponential for punch, linear for neutrality. The Pip Slope Mk II lets you slide between them continuously. For a pluck that starts soft but snaps shut like a mousetrap, dial in logarithmic attack and exponential decay. For a swell that crests slowly and fades into nothing, go linear all the way. The shape can also be voltage-controlled (via the front panel knob's CV input), so you can modulate the envelope's character over time. An LFO, for example, can make a filter sweep evolve from smooth to snappy across a sequence. This kind of dynamic contouring is rare in modules this size.

Looping Intelligence

The three loop modes are useful compositional tools. The regular loop turns the module into a precision LFO with complex shapes, good for modulating pitch or pan in evolving patterns. The decreasing amplitude mode mimics natural decay, which suits reverb tails or hand-drum rolls. The decreasing time mode is the standout: each cycle gets faster, creating a rhythmic acceleration like a ball bouncing to a stop. Use it to drive a sequencer's clock divider and you get a fill that builds tension and then collapses in on itself. It behaves more like an algorithm than an analog circuit, yet it's all generated in real time with no firmware tricks.

End of Cycle Trigger: The Silent Conductor

The "End of Cycle" trigger output connects the Pip Slope to the rest of your rack. Every time the envelope finishes, whether it's a one-shot or the last loop in a sequence, it fires a clean 5V trigger. It's good for resetting other envelopes, but it's also a compositional signal. Patch it to a noise source and a VCA, and you have a burst generator. Send it to a sample & hold, and you get a stepped random voltage on every envelope completion. Use it to clock a second Pip Slope, and you have a dual-stage modulator with interlocking rhythms. That makes the module an active part of the patch, creating feedback loops and cascading events.

Historical Context

The Pip Slope Mk II arrived in 2018, when Eurorack modules were getting bigger, more colorful, and more feature-laden, often at the cost of utility and elegance. The Pip Slope went the other way. It wasn't a Swiss Army knife with 17 blades; it was a scalpel. Make Noise's Function and Intellijel's Dual ADSR dominated the "premium envelope" space with multiple stages and complex looping. ALM Busy Circuits went for a minimal footprint and maximum flexibility. The original Pip Slope had already earned cult status, and the Mk II refined it. It competed with the idea that small modules had to be simple, packing advanced modulation into 4HP without giving up control.

It also arrived as the DIY and skiff-friendly movement gained steam. Eurorack wasn't only for wall-sized cabinets anymore; people were building lunchbox systems, travel rigs, and desktop setups. The Pip Slope Mk II, with its reverse polarity protection, compact depth, and skiff-friendly design, suited that shift.

Collectibility & Value

The Pip Slope Mk II isn't rare - ALM has kept it in steady production since 2018 - but it's highly sought after. New units sell for around £110 GBP (roughly $140 USD), and the used market reflects that. Expect to pay $100 - $130 depending on condition, with mint units from reputable sellers holding firm at the higher end. It's not a speculative collector's item like a vintage Roland synth, but it's a "forever module" that people buy and keep. The build quality is excellent: PCB-mounted jacks, sturdy knobs, clean silkscreen. Failures are rare, but there's one known issue. Some early Mk II units exhibit high-frequency parasitic oscillation on the output, a 1MHz ripple visible on oscilloscopes, reported by multiple owners. It doesn't usually affect audio or CV performance in practice. If you're buying used, ask if the unit has been tested with a scope, or plan to check it yourself.

Maintenance is minimal. There are no moving parts and no trimpots to drift. The only real wear point is the toggle switch for the 5V/8V output level. Mechanical switches can eventually fail, but there are no widespread reports of this. It's a digital-analog hybrid (the timing and logic are microcontroller-driven), so firmware updates are possible, and ALM has released patches in the past to refine behavior. Always check the official site for the latest firmware if buying used. No recap is needed and there are no aging electrolytics to worry about.