Cambridge Audio DUO MC/MM Phono Headphone Preamplifier Review

Cambridge Audio DUO Phono/Headphone Preamplifier Review

Space. The Final Frontier.

Gene Roddenberry had William Shatner (as Capt. James T. Kirk of the starship Enterprise) narrate the opening to the sci-fi episodic Star Trek and anybody who watched the original series from 1966 to ’69 growing up or in syndication – as I did in the mid-‘70s – can probably never forget Shatner’s voice, timbre or cadence as he proffered forth that line.

Much like Star Trek, space, for audiophiles or headphone enthusiasts alike, has become the final frontier as urban homes and condos continue to shrink in size and those of us with music and gear fetishes deal with the continued drop in square footage. In my hometown of Vancouver, Canada – much like any large, expensive city – it’s not uncommon to pay $2,000 for a 650 square-foot apartment, making headphone listening even more desirable from a space-saving, not-bothering-the-neighbors or cost-saving standpoint.

Two-channel listeners can now choose from myriad DSP options to squeeze the most from their space, but for those who prefer more inner fidelity than outer, headamps continue to not take up much real estate while still delivering big on sound, even for vinyl lovers. The combined footprint of a turntable and a pre/head-amplifier is minimal (I’m not getting into where or how people choose to store LPs), so when I set-up the Cambridge Audio DUO Phono/Headphone Preamplifier for review it’s not like I had to clear space for loudspeakers or drag amp stands into place for mono blocs.

No, I simply placed some isolation feet under the DUO and jacked in the unbalanced RCA out from a Rega Planar 3 and I was good to go.

As I wrote in my preview of the DUO back in November; “Little box, big, ballsy sound. That’s the first thing you notice about the Cambridge Audio DUO Moving Coil/Moving Magnet Preamplifier with integrated Headphone Amplifier. The second is the immediacy and resolution to the reproduction. With a weight and full-bodied presentation to piano and guitar, realistic tone, timbre and real meaty depth to percussion that belies it’s budget-conscious pricing.”

Nothing has changed in my estimation of the DUO, except that over time, after getting around 100+ hours on the unit, it has opened up considerably in it’s sound-staging capabilities and the timbral and tonal color has burnished slightly, becoming a touch warmer with more soulful believability to playback. For those of you who started out with a bent towards classic gear (which in my case also meant having to spend less money to get great sound) then you might know a phono/headphone output that the DUO puts me in mind of: The NAD 3020 stereo integrated amplifier. It came out in 1978 and has been referenced uncountable times over in the audio press and online for its price/performance ratio and impact on changing the landscape of high-fidelity history as one of the most significant and influential components of all time.

I bought a 3020 used for $180 in 2010 and fell in love with its warm, effortless and emotionally-engaging sound. Fast-forward 10 years and I’m time traveling courtesy of the DUO listening to many of the same LPs I owned back then, on a similarily-spec’d turntable and cart, albeit it through much better headphones. While the tonal signature is there, for a decade and about $100 more, the increase in resolution over the NAD is light-years better, especially through a set of cans like the Audeze LCD-2 Classic or Focal Elegia. When headphones like these are coupled with the DUO and the Rega ‘table, they enable a playback ability that I would associate more with something costing double what this circuit path does.

Its solid-state internal circuit board features surface-mount components, short signal paths to maintain higher fidelity is quipped with a subsonic filter to deal with low-level rumble and has a switch-mode power supply. Moving coil and moving magnet unbalanced RCA inputs with a rated impedance of 47k Ohms for MM (capacitance of 100pF) and 100 Ohms for MC, an unbalanced output, balance control, AC Mains input socket, along with a chassis ground and the rear of the unit is simple and straightforward. The DUO eschews fancy controls on its fascia with just one 6.3mm (1/4-inch) headphone jack, a power button (press to wake from sleep mode which is engaged after 20 minutes of not being used) and MM/MC buttons to toggle between inputs.


For review listening I stuck with a 'table and cart more in line with what DUO buyers would have on hand, as opposed to a reference-level turntable and MC cartridge. The associated equipment list is thus: Rega P3 Planar Three turntable with Rega Exact MM cartridge, Auditorium23 slipmat, AudioQuest NRG 10 AC cable, Focal Elegia and Audeze LCD-2 Classic headphones.

Sassy Sarah Vaughan, 1956, EmArcy MG 36089, 1999 Speakers Corner Records 180g remaster

This mid-’50s recording of bop and cool-jazz standards features Vaughan with Brooklyn composer and arranger Hal Mooney and his orchestra. The Speakers Corner remaster is pressed in Germany and through the DUO any surface noise was pushed well back into the recesses of the sound stage through the Elegia with Vaughn’s vocals imaging dead-centre and forward of Mooney’s orchestral backup which filled in beautifully behind her liquid-smooth crooning. On “The Boy Next Door” the opening strings are clearly delineated from one another and the harp is full-bodied behind the stand-up bass’ deep thrumming as the horn section glides in under the subtle intimations of the woodwinds. Separation between Vaughan and the myriad instruments is precise without ever presenting as strident or etched in the upper registers.

Moon Safari, Air, Source record label V-2848, 1998 French pressing

Versailles, France based electronic-music duo Nicolas Godin and Jean-Benoit Dunckel landed with ethereal grace and critical acclaim (being named to several top music magazines and websites as ‘Album of The Year’ and there ‘Top-10’ lists) on the scene in 1998 with this, their first full-length debut album. Equal parts downtempo, chill out and space pop, Moon Safari is filled with deep bass, Moog, glockenspiel, synth and keyboard-filled hooks and riffs laid down over driving percussion, subtle guitar riffs/plucking and vocoder-breathy lyrics sung with insouciance by Beth Hirsch. “All I Need” seems to feature everything Godin and Dunckel could play as well as a healthy dose of more courtesy of their eight-deep backup band. While the cut’s signature keyboard twinkling strayed slightly into hot territory with the treble region, it managed to ride the fine line without becoming twitchy through the DUO and the LCD-2 Classic and delivered solid baselines throughout.

Bumpin’, Wes Montgomery, Verve Records MV2114, 1975 Japanese gatefold repress

One of my favourite jazz guitarists of all time, Montgomery pulls out all the stops on 1965’s Bumpin’ which was his first album to chart in the United States reaching 112 on the Billboard 200. With a cast of characters more than 20-deep accompanying him on this LP, the sound is signature Montgomery with a full orchestra thrown in for backup. Playing through the DUO and the Audeze Classic, this album had excellent spatial and timbral reproduction with his guitar bursting forth note-by-note with real propulsion right from the centre of a deep-V 3D sound stage. On the LPs title track all the other players are beautifully arranged around him – easily discerned in a wide-band stereo presentation that wrapped around my head and saw Candido Camero’s bongos and congas emerging from behind and below my left ear and Grady Tate’s floor tom coming through with sub-bass in the spot behind and below my right ear – with Roger Kellaway’s piano tinkling and flourishes along with Bob Cranshaw’s exquisite fret and finger work on bass holding down the core of the recording as Tate’s drumming keeps everything moving along with drive and dynamism.


This is a more than capable phono/headphone preamplifier at $600 USD, at $299 USD it is an out-and-out bargain and why I named it to my InnerFidelity Editor’s Choice 2018 – Under $500 list. Dynamic, punchy, nuanced when it needs to be, this simply makes listening to LPs a fun, engaging and educational experience as it revealed a lot of detail in its resolution-abilities that had me relaxing and enjoying albums that I hadn’t hauled down from the shelves for years. If you’re in the market for an analog alternative to your current DAC/headphone amplifier combo, are looking for an upgrade from a more budget-conscience analog phono/headphone preamplifier, or are lacking a way to listen to your vinyl collection via headphones, the Cambridge Audio DUO fills out all the paperwork with ticked boxes for an audiophile-grade playback experience at a price that will raise eyebrows and satisfy pocketbooks.


  • CARTRIDGE SUPPORT – Moving Magnet | Moving Coil
  • GAIN @ 1KHZ – MM: 39dB | MC: 60dB
  • RIAA CURVE ACCURACY – +/- 0.3dB 30Hz-50Hz
  • MM: >90dB | MC: >70dB
  • THD+N 1KHZ (20-20KHZ BW) – MM: <0.0025% | MC: <0.20%
  • INPUT IMPEDANCE – MM: 47k Ohms | MC: 100 Ohms
  • CROSSTALK @ 10KHZ – MM: >85dB | MC: 75dB
  • DIMENSIONS (H X W X D) – 48 x 215 x 159 mm (1.9 x 8.5 x 6.2")
  • WEIGHT – 0.95kg (2.1lbs)

Cambridge Audio
Gallery Court Hankey Place London SE1 4BB United Kingdom
+44(0)20 7940 2200

sam1s11's picture

Hi and thanks for your great review!

I’m also having Duo and just love it. I was wondering which isolation feet you use under Duo and do you recommend using them?

Best regards,


Rafe Arnott's picture
I didn't use any, as the footprint is too small and cable weight from headphones can move it around if the feet are not physically attached. I would recommend a small marble, granite or heavy wooden base to place it on though if you think it needs it.