Digital Inputs in Amplifiers – Why Do We Need Them?
Here’s an in-depth look into the need for digital inputs in the modern day amplifier.
Sometimes, we miss profound changes around us because they happen just slowly enough for us not to fully see them. It’s only when you realise that trying to perform day to day tasks without the internet is almost impossible or arranging an event with someone who doesn’t have a mobile phone is a logistical nightmare, you become aware how much things are changing in the background. When you suddenly pay attention to something again, you realise it looks very different to how you remember it.
Two channel audio is another area where this applies. In the last few years, almost everything that was a given has been tipped on its head just slowly enough that we haven’t really noticed it. For almost the entire life of high-quality hi-fi, what separated it from lesser quality hardware was that it was literally separate. It divided into separate boxes that had very defined roles: the source (turntable, CD etc), amplifier (which may be split into pre and power boxes) and speakers. If you wanted an extra function, you added another box.
With digital, this meant that you had a device that played the digital format of your choice and that decoded it and output it via an analogue interconnect to your amplifier. On occasions, people would choose to go for a separate DAC (digital to analogue convertor) to boost performance but the end result was still the same; your amp received an analogue signal as an input. The move away from physical media has changed these rules. Many sources aren’t ones that would have even crossed the mind of a designer twenty years ago and because of this, the requirements we place on amplifiers have changed.
In 2017, it’s possible that you’ll have sources that offer a very high-quality signal but don’t themselves have very high-quality decoding. You can of course attach a DAC but you could also deal with this directly and select an amp with digital inputs as well as analogue ones. That way, you can attach whatever you need to the amp and select your input regardless of the connection it needs.
On paper, this makes total sense but making an amplifier that does this well is harder than it sounds. In the same way that when an integrated amplifier is built, care needs to be taken in keeping the delicate preamp circuitry protected from the power amp, it’s the same with the digital circuitry. The power supply to the digital section needs to be clean and free from any interference. The board must be mounted in such a way to not produce any interference anywhere else.
These engineering challenges are ones we’ve approached with a clean sheet design with the CX series amplifiers. As we intended for these models to have digital inputs from the very beginning, they have been designed to ensure the digital board is protected from the rest of the circuitry and the rest of the circuitry from it. We can design the power supplies so that there is a separate output for the digital stage of the amp. We’ve then used our experience to ensure that the digital decoding partners the performance of the analogue inputs so that regardless of what sort of connection you choose, the amplifiers deliver a consistent and excellent performance.
This means that the CXA amplifiers are designed with a view to handling whatever components your system uses in such a way that you don’t need to worry how they’re connected. With the CXA80, the USB input means that pretty much any computer can be turned into a digital source that offers enormous flexibility.
As with a lot of things we do, our decision to fit digital inputs to our amplifiers does not mean we believe that separate source equipment has fallen by the wayside (we still make these just to prove it!) It represents our recognition that the requirements we have of source equipment is changing and that in order to meet the ever-changing requirements, we need to change with it. Connect what you want, how you want and enjoy the music.