Premium Integrated Amplifier

Our "Sound First" design process ensures the 651A will make all your music sound amazing. And with 75 watts of amplification per channel, a USB audio input, and a front facing 3.5mm jack input for easily connecting iPods and MP3 players, the 651A is packed with features as well.

Sound First Design

We developed the 651A with one simple purpose:

To allow users to enjoy music from any source in fantastic quality. To find out how we achieved that, watch the video above.


For many people their computer has become more important than their towering CD collections. However, poor quality soundcards plus jitter means audio performance from PCs can be quite poor. Fortunately the 651A features a USB audio connection so you can simply plug your Mac or PC directly into the amplifier to instantly enjoy a whole world of digital music streamed from your computer.

Our in-house developed USB audio processor extracts audio data directly from your PC hard drive - bypassing its soundcard - and takes care of the critical digital to analogue conversion process, bringing clarity and warmth to otherwise dull and lifeless MP3 files.


Rather than overcomplicating the 651A, we’ve just invested in the components that really make a difference to the sound you hear.

  • We use a premium toroidal transformer which is key to unruffled performance with music of all types.
  • Separate transformer taps for left & right channels, twin rectifiers and separate PSUs for dual-mono operation of the left and right power amplifiers all add to the audiophile specification.
  • High grade film type volume ensures the 651A also performs as well at low levels as at higher volumes.


Whatever hi-fi speaker you choose, the 651A is designed to drive any model with ease. Our retuned output stage featuring Sanken output transistors gives excellent bass response and dynamic control. Additionally our proprietary CAP5 system ensures unrivalled peace of mind against overloads, faults and clipping.


Connection support for analogue sources like CD players, iPod docks and tuners is better than ever so whether you store or stream music from your computer, iPhone or maybe you prefer the luscious sound of good old vinyl, the Cambridge Audio 651 will make all your music sound amazing.


75 Watts of class leading power per channel fills even the largest rooms with encompassing audio whilst a whole host of custom designed components together with our perfectionist approach to design means that whatever you're listening to, it will simply sound fantastic.

  • Power output75W RMS into 8 Ohms
  • THD (unweighted)< 0.002% @ 1kHz, 80% of rated power
    < 0.03% 20Hz - 20kHz, 80% of rated power
    < 0.02% 20Hz - 20kHz @ 10W
  • Frequency response5Hz - 50kHz (-1dB)
  • S/N ratio (ref 1w)>92dB (unweighted)
  • Input impedance47k Ohms
  • Power amp damping factor>100 at 1 kHz
  • Max. power consumption600W
  • Standby power consumption<1W @ rated mains
    Shelving, ultimate boost/cut +/- 7.5dB @ 20Hz and 20kHz
  • USB audio inputUSB audio 1.0
    16 bit 32kHz, 44.1kHz, 48kHz
  • ColourBlack or silver
  • Dimensions (WxHxD)430 x 120 x 350mm (16.9 x 4.7 x 13.8")
  • Weight8.4Kg (18.5lbs)

Hi-Fi Choice (GB, )

"It simply has no weak areas, and has various strong ones that frankly you wouldn't expect at this end of the market."


Hi-Fi Choice (GB, )

"Excellent affordable integrated amplifier, with an endearing character... ...A true everyman's amplifier this comes festooned with facilities."


Hi-Fi News (GB, )

"The 651A is a confident performer, with excellent levels of clarity balanced by an impressive soundstage... ...what sets the Cambridge Audio 651A apart is its sound quality which makes it exceptional value for money."


What Hi-Fi? (GB, )

"651C is a good-looking, spacious-sounding disc spinner... ...651A is a meaty, powerful-sounding amp."

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Hi-Fi World (GB, )

"All in all, these careful and considered designs provide a good basis for enjoyable, long term listening which, for any budget system, is worthy praise."

Diapason D'Or )

651C and 651A both win a prestigious French award, a Diapason D'Or!

Witch Doctor (NZ, )

"...for the money, this gear is gold, particularly the amp... A highly, even wildly-recommended combination."

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