Hi-fi spirit for the Retro Radio.

Real reception for LEGO® 10334. Hands-on tuning. Instructions and extra parts included.

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AM/FM reception Mod kit for LEGO® 10334 Requires extra parts

Origin

Why build this?

Cosmic Voice was founded in ~1960 by my grandfather to sell radio kits and other educational materials. He also literally wrote the(a) book on car radios. When LEGO released the Retro Radio, I was excited by the concept, but I felt like something was missing from the execution: a radio. It felt like the perfect opportunity to bring the Cosmic Voice brand back to life and to realize the potential of the set. It's taken a little bit longer than I planned to get it to this stage, but I'm pleased to finally share it with you.

AM / FM

Analog tuning · Si4831 receiver

Knobs

Both functional · smooth* action

Mod

For LEGO® 10334 · adds parts

What’s in the kit

AM/FM receiver board (assembled)
Mounting hardware & wiring
Step‑by‑step instructions
Additional LEGO® elements for functional knobs & dial

What you provide

LEGO® Retro Radio set (10334)
4 × AA batteries
Nostalgia

This is a modification kit: it reuses most of 10334’s parts and changes the interior layout to make the knobs and dial functional.

Design notes

Is this as easy as a lighting kit to assemble? Sadly, no. In order to have functional power and tuning knobs, some of the kit innards had to be removed and reorganized. Is it a real radio? Yes. The tuning scale connects to a Si4831 IC receiver for AM/FM, with a smooth mechanical feel at the front and a tidy mount at the back. You’ll reuse most of the original parts, add a small set of new elements, along with a couple of small 3D-printed parts to interface the electronics with the LEGO controls. The look stays Retro Radio; the behavior becomes a radio. Were there easier ways to do this, like hiring an engineer who had designed radios before? Sure, but parsing my favorite TV character, it ain't easier I was after.

The board is currently on its third design iteration - revision C. If there's enough interest in the project, I'll move to a revision D with improved features for wider production.