I’m Ben from Cambridge Audio.
We’re known for making an awesome range of hi-fi products but today I’m here to tell you how our clever digital preamps work.
There are usually two parts to an amplifier: the part that controls volume and input selection, the pre-amp
and the part that actually drives your speakers, the power amp.
An analogue preamp, like our 851E, has analogue audio inputs
such as RCA or XLR for music sources which have a fixed analogue output, like a CD player or turntable.
Whereas a digital preamp, like the 851D or CXN, usually combines DAC functionality with digital inputs
such as optical and coaxial for music sources which have a digital output, like the CXC.
Both types of preamp then provide an analogue audio signal to the power amp, which in turn drives your speakers.
Normally a source product, like a music streamer, needs to be connected to a preamp or integrated amp, because its audio output is fixed at one level.
But, in our DACs and digital music players, like the 851D, the CXN, 851N and Stream Magic 6, we build-in an optional digital preamplifier.
By activating the digital preamplifier inside the player, the selector knob also becomes a volume knob, and the analogue output becomes variable
in other words the player now has built-in volume control.
This means it can be connected directly to a power amp like the 851W, without the need to go through an additional analogue preamp.
Not only does this simplify the system, but it also saves the cost of an analogue preamp, because you no longer need one!
This means you can maximise the rest of your system with great speakers and cabling.
There’s also an important benefit for sound quality too.
With a traditional setup, the player is connected to an analogue preamp, which in turn is connected to a power amp.
These multiple analogue connections create a chain of products which are all subject to analogue signal degradation, which damages sound quality.
By using a digital preamp built in to the player, we’re using the simplest signal path, with no lengthy chain of products
minimising any signal deterioration and giving the best possible sound.
Most digital preamps from other manufacturers simply aren’t good enough to be able to do this.
To achieve volume control, usually a digital preamp compresses the digital audio signal. This is known as bit-reduction.
It works, but it’s certainly not hi-fi quality because the audio signal is being compressed and data is being thrown away.
But at Cambridge Audio, we're cleverer than that so we do not do this.
Instead, our digital preamps are driven by a powerful Digital Signal Processor or DSP.
The volume level is fully controlled by this DSP. The audio signal is not compressed and no data is thrown away.
This means that the audio signal remains at full resolution and sounds just as the artist intended: awesome!
We use our fantastic, DSP driven digital volume control in many products across our range
including the CX and 851C series.
In our network music players, having the built-in digital volume control also means that the volume can be fully controlled by the Cambridge Connect app.