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Prism Callia
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Professional Education

Martin Pipe discovers that the pro-audio heritage of Prism Sound’s Callia DAC/headphone amplifier is manifested in its sound.



A while back Prism Sound discovered that audiophiles, notably in the Far East, were buying its professional DACs for home use. ‘No-compromise’ devices like Lyra and Orpheus might be expensive (they’re not at the top of the Prism line, either) but money is no barrier to the dedicated! This unintended market gave Prism founder and marketing director Graham Boswell the idea of producing a DAC specifically for hi-fi enthusiasts. 

   The result is the British-designed and made Callia (in the Prism tradition, a Greek word – here meaning ‘beautiful voice’). Its pro-gear influence is evident; the visual resemblances to the company’s existing Lyra models (which also boast pro-grade ADC facilities) and Callia are obvious.

   Another similarity between these two compact units goes beyond skin-deep – both are intended primarily for USB use. Just as the Lyras are pitched at the modern musician who uses a laptop as a production tool, the Callia is aimed at the modern hi-fi enthusiast who uses a laptop as a playback source. In both cases, the USB interface  is UAC2-compliant asynchronous with Prism’s proprietary ‘CleverClox’ PLL circuitry minimising jitter. In the Callia, the latter is also active on the conventional optical and coaxial S/PDIF inputs that are provided for CD transports, streamers and the like. They are selected automatically, with front-panel push-button override.

   The Callia’s digital volume control is surrounded by a ‘halo’ of LEDs that indicates the current level; it can be defeated via a rear-panel DIP switch, so that the output – on unbalanced phonos and balanced XLRs – is fixed to full level, and the Callia’s full dynamic potential realised. 



You may not get a remote but Prism does supply this

impressive 4GB USB stick containing the Windows

drivers and operating manual in PDF form.


No remote handset is supplied. However you do get an independent analogue volume control for the headphone amplifier, the sensitivity of which can be adjusted by two more DIP switches. The 6.3mm output (no provision for balanced ‘cans’ here) joins it on the front panel, alongside a row of LEDs that indicate the currently-selected source and the type of signal being converted. They are particularly useful when using the Callia with a computer via USB as you’ll be able to troubleshoot software configuration issues and ensure that the unit is getting your music in the best possible way.


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