Hardware Reviews

Prism Sound Callia


Prism Sound’s reputation preceded it when it finally entered the domestic hi-fi business earlier in the year. The Cambridge based company has been making converters for the studio market since 1987 and its top pro DAC is a cult product amongst those in the know. PMC founder Peter Thomas has one in his main system for instance, and he’s tried more than most in his quest for digital audio ecstasy. That model used to cost about six G, so when Callia appeared at the Munich show I was expecting something rather less affordable and perhaps a bit bigger. But Callia contains many of the design principles of Prism Sound’s best models including fully balanced circuitry, ‘CleverClox’ jitter busting tech and their USB platform.

While their big pro audio converter, the DA-2, is limited to 96kHz sample rates Callia is good up to a typically audiophile 384kHz (actual conversion is 192kHz), and it is DSD capable too albeit up to a fairly standard DSD128. However, this DSD implementation is the first to include the option of adjusting signal to noise to accommodate so called ‘hot’ recordings (found on some SACDs made after March 2003), those that exceed the 0dB ceiling normally applied in the studio. Prism Sound have also paid attention to the headphone output, which is a high current, low impedance design that will work with the majority of headphones on the market. Variations in sensitivity can be balanced with dip switches on the back panel which is very useful.


Callia in


Callia is a nicely put together DAC with a separate volume control for main and headphone outputs and the ability to bypass the former by moving another dipswitch on the back panel. Nicely packaged and finished, almost the best thing about it is the USB stick that contains manuals and drivers for Windows computers. This looks like it was designed for military applications, underwater, but I didn’t test that side of things! The Callia’s back panel has USB B, coaxial and optical inputs alongside outputs on XLR and RCA phono sockets. All the phono sockets are good quality examples. You can tell by the back panel shot that this is not a full width component, it’s just over 11 inches wide so won’t take up too much real estate in your system rack.

One thing that’s not immediately obvious on this DAC is how to change inputs, this is largely because it has an auto mode that detects signal and switches to the live input. If there is more than one such feed the power button doubles up to provide this function. A short press switches to the next input and if something live is connected then the bit, sample rate and format is revealed with a row of LEDs. You have to read the manual to fully understand the lights but it’s a useful indicator that signal is present.


Callia rear


I started out using Callia with the USB feed from a Melco N1-A server over a Vertere HB cable, a very good cable indeed. Used thus Patricia Barber’s ‘Company’ had all the weight and texture of the double bass and its notes stopped and started precisely but without glare. The character of the drum recording was also clear, I got the power and clarity of image one hopes for at this price alongside an honesty and transparency that made the most of everything played. The Callia is as Prism Sound describe, a neutral, nothing added DAC. It doesn’t sound as if it has been tuned to sound sparkly and open or lush and smooth, it sounds as different as each of the pieces of music it converts. More expensive converters reveal more detail, more body in each note and thus greater depth to images. One of these was the twice the price Rockna Wavedream but the other was the more modest Primare DAC 30 at £2,000. This is not DSD capable nor does it have volume control or headphone output but does offer more inputs.

A closer competitor is the Mytek Brooklyn (£1,740), a more compact DAC with features coming out of its ears, including but not limited to analogue inputs, MQA decoding, remote control, variable filters, AES/EBU input and wordclock connections. It sounds lean and fast compared to Callia, quite gripping but not as musically enjoyable nor as relaxed.


Callia front low 0


Back with Callia I really enjoyed ‘Always Hopeful’ from Bugge Wesseltoft’s OK World album, this offered up glorious instrument timbre from a fretless bass and superb musical flow. The fingers on tabla of the next track were also very convincing and the whole piece remained clear and coherent regardless of how busy the musical proceedings became. With a coaxial input from a Cyrus X Stream the situation remained much the same, the aesthetic side of the sound was enhanced by the connection, coax seems a little smoother through the midband and treble. The sense of immediacy was also very strong with the aforementioned tabla, as was the imaging. The tonal balance was more even with the direct USB connection but this source provided a a very  musical and engaging result that encouraged listening, Kurt Vile’s excellent ‘Pretty Pimpin’ sounding articulate, solid and tight in all the right places.

I was able to directly compare the two connection systems when an Auralic Aria Mini turned up, this is a streamer with both coax and USB outputs (and analogue) that has a more even balance than the Cyrus and a great control app. This showdown made a good case for the detail levels available via USB but swayed me to coax by virtue of this connection’s musicality. But in both cases Callia sounds great, and that’s what counts. Give it an even better source, the CAD CAT USB server, and you get more detail and greater realism, the room acoustic on Amandine Beyer’s violin was as clear as the Bach tune she was playing, or so it seemed. Timing is a key element in music as in life and this DAC is pretty well transparent to it, give it a complex arrangement or a simple groove and it remains bang on the money. With this source the levels of detail increased but so did the music’s power to engage and it was difficult not to be swept away by its charms.


USB stick


What Prism Sound have done well with Callia is to create an honest and transparent converter that doesn’t need smoothing or exciting because it delivers music in a totally coherent form. Something that quite a few DACs even at this price find hard to achieve, they often fudge the issue with a soft/smooth sounding output stage or go for a lean, forward balance to inject some extra excitement, but this inevitably results in a fatiguing sound. Put on Muddy Waters playing ‘Feel Like Crying’ and the groove, the space and the tone are irresistible, it makes you want to hear more of his acoustic blues. With the rather more diverse sounds of Schumann’s Piano Concerto the flow and dynamics of the piece are equally engaging, you get the charm and the power in equal measure and cannot simply use it as background listening, it clearly warrants rapt attention.

The Prism Sound Callia is one of those ‘does what it says on the tin’ products, it lets you hear just how good the source that you connect is and by extension, what the musicians were doing in the studio or on the stage, not to mention the character of the recording. Build quality is high and ease of use couldn’t be better, some of the competition offers more in the way of features, but the absence of a remote for volume is the only real feature omission. Add in Prism Sound’s enviable pro audio heritage and excellent build quality and Callia looks more and more like a DAC that’s very hard to beat at the price.

See Prism Sound at British Grove here.


Type: Solid-state PCM/DSD digital-to-analogue converter/preamplifier
Digital Inputs: Coaxial, Toslink optical, USB 2.0
Analogue Outputs: single ended on RCA, balanced on XLR, configurable for fixed or variable level
DAC Resolution/Supported Digital Formats: All PCM from 44.1 kHz to 384 kHz with word lengths up to 24-bit, DSD64 (2.8224MHz) and DSD128 (5.6448MHz). PCM sample rates above 192kHz are down converted.
Headphone output: 3 level sensitivity
Variable DSD headroom
Output Voltage: RCA 2Vrms, XLR +14dBu at maximum
Dimensions (HxWxD): 50 x 285 x 242mm
Weight: 2.1kg
Accessories supplied: USB memory stick, USB and IEC leads

Price when tested:
Manufacturer Details:

Prism Media Products Ltd
T 01353 648 888




Jason Kennedy

Distributor Details:

Prism Media Products Inc
T +1 973 983 9577

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