Hacking a valve radio to build the ultimate iPhone speaker

A new project bridges analogue and digital and captures the audio quality and romance of times past. Valve radios and gramophones were manufactured from 1930 to the 1960s.

They had a dual purpose as an audio device, and because of their size, a piece of furniture. They typically have a striking design in bakelite or wood.

My grandparents had a large radio and gramophone set housed in a freestanding wooden case.

It used to take several minutes for the valves to warm up and spring into life. I remember the high-end wooden lacquered case. The rich, deep bass drifted softly throughout the house.

The mainstream production of the transistor in the 1960s saw off the valve. It kickstarted the modern era of miniaturisation and low-cost consumer electronics.

Valves are now a luxury celebrated by high-end audio fans. The audio quality of valve amplifiers even compared with modern solid state electronics is extraordinary.

But while valve hi-fi equipment costs up to £1,000, and often more, vintage valve equipment is affordable.

You occasionally spot old radios and gramophones in antique stores or flea markets. They’re priced around £50 to £100 depending on condition and vintage.

Help is never far away to make sense of the market. There’s a large community on the web of valve enthusiasts and content including specifications and manuals.

We recently spotted a Stella ST236A radio on eBay. It’s a magnificent six valve set manufactured in the 1950s and housed in a large bakerlite case.

There’s a richness, depth and tone to the audio quality. There’s also a romance in knowing that this is a 60-year-old piece of kit in perfect working order.

The radio has three bands and a gramophone input. The tuner compares well with a modern digital radio set, especially if you plug in an external aerial.

At the suggestion of a friend I connected my iPhone to the gramophone input using a home-made cable.

The audio pickup was low but improved dramatically whenever the gramophone button was pushed down. A spray of contact cleaner from Maplin and brush with an old toothbrush restored it to fully working order.

Connecting an iPhone to a valve radio and streaming audio from iTunes or Spotify is a magical experience. It appeals to my obsession to restore and tinker with old technology.

The next step was to go wireless and replace the cable with a Bluetooth radio receiver and connect an iPad, iPhone or any other Bluetooth-equipped audio device.

So-called wireless active speakers have emerged as a new audio category to serve the growth in mobile devices, and demand for something better than a tiny mobile phone speaker or headphones.

I travel with a small cylindrical device that I bought from Mapin for £30 that doubles up as a speaker phone. Brands such as Boss, Pioneer, Sony and Sonus are making a bid to restore audio fidelity to mobile device.

Adding a Bluetooth radio to the valve radio was straightforward.

We bought a tiny (11.2 x 9 x 2.4 cm) black box of electronics from Amazon for £13 and made another homemade cable to connect it to the radio.

The Bluetooth radio (JUSTOP BTR006) pairs with any Bluetooth device to capture an audio stream, and plugs into an amplifier or speaker. It has an internal battery that is charged via a USB connector.

The result is magical. It crosses the worlds of analogue and digital, and decades of audio history. You can keep your fancy Sonus box. Vintage wins.