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At a glance
The open Caldera in Koa, as a numbered one-off set from ZMF, with an aluminium or Mg12 chassis. Delivery in approx. 6–10 weeks.
30-day returns on ZMF too
We take back every configuration you can select here, even if ZMF builds it after you order. Only genuine custom builds made at your request, such as a special wood, are excluded.
At a glance
The open planar flagship in numbered one-off Koa sets
Numbered one-off sets. ZMF releases the Koa Caldera as numbered one-off sets, and only a few remain. You order directly here, with the chassis of your choice: aluminium or Mg12 magnesium. We then reserve a matching set at ZMF for you and let you know the set number and delivery date. Delivery takes approx. 6–10 weeks. If no matching set is left, you get the full amount back.
For this LTD edition ZMF built the Caldera Open in Koa. Koa is a Hawaiian wood with golden-brown to amber tones and lively grain. It grows slowly in volcanic soil, is dense with a silky lustre and was once used for outrigger canoes. Today it is one of the rarest and most sought-after hardwoods.
ZMF does not release the Koa Caldera as a freely configurable series but as numbered one-off sets (LTD #1 to #16). Each set has its own fixed specification: black aluminium or Mg12 chassis, rod and grille colours, some with a BBB strap. The wood of every set looks different from the photos.

Technology and tuning come from the Caldera Open: an 80 mm planar driver with the patented CAMS magnet structure, 60 Ω and the Caldera pad system. As with the Caldera, ZMF includes a second pair of pads.
Not sure if the ZMF Caldera Open LTD Koa is the right model for you? In our ZMF Buying Guide we put every model in the lineup head-to-head.
The Caldera Open is the model for anyone who wants to combine the technical strengths of a planar magnetic driver with the natural character of a dynamic driver – with high resolution, an expansive stage and powerful, controlled reproduction. The Koa sets are meant for collectors who want exactly this flagship in a rare wood.
| Design | open, circumaural |
| Driver | planar magnetic, 80 mm, CAMS |
| Impedance | 60 Ω |
| Sensitivity | ~95 dB/mW |
| Weight | 490–550 g depending on chassis (standard model) |
| Connector on the headphone | 2× mini-XLR |
| Wood | Koa |
| Specification | depends on the numbered set |