Prism Sound Callia DAC/pre/headphone amp review

Prism Sound Callia


Build quality




Ease of use


Sound quality





  • Studio quality performance
  • Simple set up
  • Clarity of reproduction
  • Excellent headphone amp
  • Superb DAC


  • Parting with almost £2k

prism-sound-callia-reviewBack in August I was fortunate to be invited to the launch of Prism Sound’s Callia DAC. Prism Sound might not be a familiar name to most but they have been producing top-end kit for recording and mastering studios for years. I have had the added bonus of living with the Callia for a while.

Prism Sound, the UK-based audio manufacturer has made highly regarded studio products including its premium analogue Maselec mastering EQ to a variety of multichannel Analogue/Digital and Digital/Analogue converters. These would not be found in every studio though. We are talking high end, and with a price tag to match.

This year, Prism Sound has not so much dipped its toe in to the domestic market, but dived right in. Will the Callia make a splash?

Prism Sound Callia design

The  Callia unit is clothed in a dark-grey and measures 285 x 242 x 50mm (including its rubber feet). These dimensions are pretty much a 3/4 of a rack space wide by 1 U high, in studio speak.

The front panel is tastefully anodized and the whole look and feel of the DAC is elegant whilst retaining a functional air about it. I can certainly see that it is related to the Lyra from the front.

callia-and-mf-v90-bluThe uncluttered look lends itself to both high-end Hi-Fi enthusiasts and new-comers alike. The controls are simply a large line-output volume control, a separate, smaller headphone volume control, and a standby/input selector switch. Other than that, there is the headphone jack and a series of indicator lights and nothing much else to report.

One bank of LEDs indicate input: Auto, TOSLink SPDIF, RCA SPDIF, USB.  The second bank of separate LEDs reveal the audio input status — a DSD LED and a PCM LED. More about those later.

I/O panel

Connectivity is taken care of by a set of balanced XLR line outputs, a pair of unbalanced RCA line outputs and three digital inputs (SPDIF TOSlink, SPDIF RCA, and USB 2.0).

The 32-bit PCM audio path and sample rates higher than 192 are only active if you go via the USB input. The Callia comes with a rather nice-looking USB stick that contains the required software to run on your laptop or PC.

prism-callia-rearWhile we’re around here, it makes sense to also point out the series of small DIP switches. These allow you to cater for headphones that need a bit more grunt. The other switches puts the Callia in to pre-amp mode with the main volume being controlled by your main amp.

Prism Sound Callia performance

Input status lights

Righty, let’s get the read-out sorted before  we start. Stick with me and we’ll get through this together.

The DSD (Direct Stream Digital) sample rate is indicated by the DSD LED being lit plus one of the following. If the 2X light is not illuminated it signifies 2.8MHz; if the LED is lit this indicates a 2X 2.8 MHz DSD sample rate — 5.6 MHz.

When playing PCM (Pulse Code Modulation), the sample rate is indicated by either the 44.1 kHz or 48 kHz LED being illuminated, plus either the 2X or 4X LED.

This means that 24/96 will be indicated by the illumination of the 48K LED and the 2X LED (48 x 2 = 96), plus the 24-bit LED.

prism-sound-callia-dac-headphone-amp24/192 material shows the 48K LED, plus the 4X LED (48 x 4 = 192) and the 24-bit LED.

A 384 sample rate is indicated via illumination of the 48K LED, the 4X LED, plus the 2X LED (48 x 4 equals 192, and192 x 2 equals 384).

Real 32-bit integer audio is indicated by the 24-bit LED glowing red instead of blue. When a 16-bit recording is played, the 24-bit light does not glow at all.

Yes, this looks a bit convoluted and complicated but you soon start to recognise the read out at a quick glance.

Digital analogue converter

The Callia is loaded with an ARM Cortex digital processor, but with Prism Sound’s own circuit architecture and reclocking stages. The latter is the aptly named CleverClox hybrid phase-locked loop. This acts as clock recovery taken from either local or S/PDIF input.

callia-angleThanks to that tech, you get ±50ppm local clock accuracy and a greater than 60dB/decade above 100Hz jitter rejection. The DAC boasts a noise spec greater than -115 dB (20 Hz-20 kHz), according to Prism Sound’s specs.

Sound quality

Set up was simple. There was just a bit of guesswork required to get the DIP switch right for it to run as a pre. There may well be a guide in the production boxes but I scampered away with this model from the press launch. When you run the Callia in this way the main volume lights stay off as this control is disabled.

callia-usbI had it running from my Lenovo Yoga 2 Pro via the included cable playing files stored on my QNAP NAS in no time. Being Windows, it needed the USB-packed software which was sorted quickly.

Wow! I never thought that my digital library could sound so much better simply by putting the Callia in the chain.

I feel that I must point something out though. The Callia is truly studio-grade gear. This means poor rips or dodgy records will be shown for what they really are. There is nowhere for your digital recordings to hide.

prism-callia-angleIf you are looking for added warmth or something akin to a ‘beauty’ filter, look elsewhere. Instead Prism Sound’s Callia will give you the unedited truth. With that comes more insight into what the engineers, producers and artists had in mind when the tracks were being recorded.

I found myself entranced and genuinely more involved in the listening experience. This was especially true when using the Callia’s headphone port with my Oppo PM-1 headphones.

I actually just sat there for the entire night with a bottle of wine and tune following tune. It was as if I was listening to ‘Rumours’, ‘The Fragile’ and ‘So Far, So Good…. So What?’ for the first time.

Prism Sound Callia review conclusion

The Callia is open and detailed with plenty of width and depth in the stereo presentation. To say that I was impressed by this piece of equipment would be an understatement. My home Hi-Fi is fairly decent but the Callia made it sound so much better. Truer. More dynamic.

The DAC is worth the not inconsiderable sum just by itself but, with that headphone amp, it is almost a bargain if within your price range.

I so would if I could!