No products in the cart.

Dioscuri Redux: Castor & Pollux II by Winterbloom

Most likely to spread awareness about the phenomenon of heteropaternal superfecundation, the good people at Winterbloom just released the second version of their popular Juno 106-inspired dual oscillator: Castor & Pollux II.

So what is C&P2? In Winterbloom’s own words:

“Castor & Pollux is a dual oscillator that echoes back to the legendary Roland Juno but shines with its own unique, massive voice. It contains two digitally-controlled analog oscillators implemented using a faithfully modernized version of the original Juno 106 design. It builds on the classic ‘80s sounds of its inspiration by using the second oscillator and internal LFO to layer in thick detuned sounds and harmonically complex hard synced waveforms.”

Now we know more about the module, let’s get a feature rundown.

Castor & Pollux II Features

  • $289 retail price
  • 14 HP (including expander = 16HP)
  • 2 individual, mirrored oscillators
  • 3 main pitch outputs (⍺ oscillator, β oscillator, and a mixed output w/ crossfade knob)
  • 9 total outputs (3 on main panel, 6 on expander)
  • Tracks over a 7 octave range
  • Separate pitch CV inputs (0V – 6V) and knobs (-1 to +1 octave, configurable)
  • Separate pulse width CV inputs (0V – 5V) and knobs
  • Three waveshape – ramp, pulse, and sub – mini-pot mixers (controlling amount of each wave in the mixed output)
  • Mode button giving access to 3 additional ‘Tweak’ modes (these adjust C&P2’s overall functionality)
    • Chorus mode, the default mode, uses the internal LFO to modulate Pollux’s frequency.
    • LFO PWM mode uses the internal LFO to modulate both oscillator’s pulse width.
    • LFO FM mode uses the internal LFO to modulate both oscillator’s frequency.
    • Hard Sync mode produces metallic sounds by syncing Pollux’s ramp core to Castor’s.
  • An internal LFO
  • Hardware chorusing
  • Hard sync (Team Hard Sync!)

That’s a lot of oscillator for under $300.

Ok, so what’s changed from version one to version two? In one word: Interface.

Oh you want more detail? Luckily, Winterbloom has us covered again. Changes made by the team include:

  • Replacing the pitch trimpots with large knobs
  • Replacing the pulse width, LFO, and crossfade trimpots with knobs
  • Moving the input and output jacks to the bottom edge of the module
  • Moving the individual waveform outputs to a separate expander
  • Consolidating the two separate circuit boards into a single board
  • Adding additional ESD protection to all input jacks
  • Adding an additional LED

You might have noticed C&P2 has 7 jacks on the panel vs. 13 for the original… curiously missing from this change list is the 2HP expander that bridges the gap, giving you access to the individual ramp, pulse, and sub waveform outputs (non-mixed).

UX for The Win

This is how you update hardware. Keep all the functionality while improving usability & overall design. Getting rid of the ‘all mini-pots all the time’ approach to the panel makes a massive difference, just on visual differentiation alone.

We know lots of synthesists who are massive fans of the Castor & Pollux, so expect to see its updated distinctive glow populating racks in the next few weeks.

Castor & Pollux II is available as a DIY kit ($259) and as a fully assembled module ($289). Winterbloom’s documentation is stellar. We’ll post it in the quick links, but the manual and DIY build instructions have excellent imagery and overall attention to detail. They even have night mode!

Eurorack is an amazing community because of unique manufacturers like this. Support Winterbloom by purchasing Castor & Pollux II directly from their website.

Sound Demo

C&P2 has the same features & firmware as C&P1, that means we get to embed this awesome sound demo from Read Means Recording! Of course, Jeremy makes the oscillators shine.

Castor & Pollux II Quick Links

Note: all imagery courtesy of Winterbloom / www.winterbloom.com.

Related Articles


Meet Nightlife – After Later Audio’s New Mixer Ecosystem

If you were lucky enough to attend Knobcon last year, 2023 was clearly the "Year of the Mixer." Larger offerings from Noise Engineering, 1010 Music, and Boredbrain got significant coverage but there's one company who seems to have snuck under the radar: After Later Audio and the modular Nightlife Mixer Series.

Modular World – Patch-On: Reverb Challenge

Weighing in at almost five and half hours, the Modular World Patch-On: Reverb challenge is an epic show of 50 artists across 15 countries.

Patch-On: Reverb – A Modular World Interview with Johno Wells

In celebration of the upcoming Patch-On // REVERB patch-challenge video we talk about the show, the scene, and the mind behind one of the most important creative outlets in our global modular community.

DivKid Ochd – Halloween Wallpaper Set

As promised, here are six hi-res desktop wallpapers and one (you have to edit people) iOS wallpaper from our DivKid øchd Halloween photo session.

Meet the New DivKid Ochd Expander: [ø]4^2

We've got a hunch that 'ochd expander' will be...
Modular Bias
Modular Bias
Modular Bias gets support from partners, affiliate links, and site ads. If you use an ad blocker we totally get it, even if the brands & services we aim to promote will be totally kickass. Purchasing products via our links adds no cost to you and massively helps fund site development & new content. We also love coffee. Thanks for reading and stay safe.


Please enter your comment!
Please enter your name here