Effect Audio Code 23 MK II | Copper IEM Upgrade Cable

The best copper cable I've ever had!

I'm a new audiophile and this is my first extensive cable review so bear with me. Code 23 MKII + Wider soundstage + Lots of bass (still fast & controlled) + More open and immersive presentation + More engaging treble - Slightly less air - Slightly bulky Compared to a typical thinner silver cable I have (26awg per core 8 core total), Code 23 MKII brings a stronger sense of space, weight, and presence—almost like the sound is being projected outward rather than contained. Soundstage & Space What the Code 23 MKII does most noticeably is expand the stage sideways. Compared to the silver cable, everything feels more spread out left-to-right. The space opens up, giving instruments more room to breathe. It’s not that the entire stage becomes dramatically larger in every direction, but the horizontal expansion is very apparent and natural, which changes how the whole presentation feels. Because of this, the music comes across as more open and outward-facing, rather than centered and enclosed. Separation & Layout With that wider presentation, elements naturally feel more separated. Compared to the silver cable, instruments don’t feel as clustered together. Instead, they are laid out more clearly across the stage, making it easier to follow different lines without effort. This isn’t about more detail—it’s about how that detail is spaced out. Bass Presence The Code 23 MKII adds a clear sense of weight and physicality in the low end. Compared to the silver cable, bass notes feel fuller and more grounded. There’s more body behind kicks, basslines, and low orchestral elements, giving the sound a stronger foundation. At the same time, it doesn’t feel slower—just more substantial and present. Midrange Placement The midrange itself doesn’t shift dramatically in tone, but it feels different in context. Compared to the silver cable, even though vocals and instruments sit within a larger, more open space, they still feel the same and naturally integrate into the overall stage. Treble Character In the treble, the Code 23 MKII feels a bit more forward and expressive. Compared to the silver cable, high-frequency elements stand out more—they have more presence and a slightly more energetic edge. It does have less air, but what it has feels more noticeable and lively. Overall Character Compared to the typical braided silver cable, the Code 23 MKII shifts the presentation toward: More width and openness More bass weight and physicality A slightly more expressive, energetic top end The overall effect is a sound that feels larger, more engaging, and more outwardly projected, without losing control or becoming fatiguing. Conclusion The Code 23 MKII isn’t about improving technical performance in isolation—it’s about changing how the music occupies space and carries energy. Compared to a thinner silver cable, it offers a presentation that is wider, fuller, and more physically engaging, making the listening experience feel more expansive and immersive. If your preference leans toward a sound that feels open, grounded, and bold with bass enhancement, the Code 23 MKII delivers that character very convincingly. Testing gear: Fiio K13 R2R, QX13, EPZ TP55 Moondrop Psyche, Blessing3.

Code 23 mk2

This cable looks and sounds fantastic. 4 stars because it is a little thick and stiff and no chin slider. Still a great cable and I really enjoy it

Great warm sounding cable

This is one of the better sounding copper cables I’ve heard. It’s a little too stiff for my preference though