What is a Pre-Amp?
A Pre-amp is an electronic amplifier that takes a small electrical signal and converts this to a larger version, known as Line Level. This is then ‘loud’ enough for a power amplifier to interpret and amplify further to a listening level.
This signal can be restricted with the use of volume control to prevent damage to your speakers. This is necessary as producing the maximum signal possible from both units may damage your speakers and allows control to establish a comfortable listening level.
A pre-amplifier also has the ability to ‘clean’ a signal and reduce distortion and ‘hum’ from the audio signal as it is amplified. This ensures that you hear more of the music and less background noise caused by the equipment in use.
How is Digital Pre-Amp (DPA) Mode different to a regular Pre-Amp?
A digital source does not produce a signal in the same way as an analogue source. An analogue source is gradual, as with a sound wave. This can be at any volume level and include the distortion and ‘hum’ previously mentioned.
With digital, there can be no variation in signal power, this is either ‘on’ or ‘off’ as in the image below.
Digital Wave Analogue Wave
As a digital source already produces the maximum output available, the ‘amplification’ part is therefore unnecessary.
How does this relate to my 851N?
As the amplification of digital sources is not necessary, it could be easily determined that a pre-amplifier may be an irrelevant feature, however, this assessment may be misguided.
As digital sources produce the maximum output, there is still a necessity to prevent this large signal from damaging your speakers.
For this reason, when Digital Pre-Amp (DPA) mode is enabled this allows volume adjustment to be performed by the network player before being converted to an analogue audio signal. This, in turn, prevents the Power amplifier from delivering a full signal to your speakers and damaging them.
Helpful tips and ways to prevent damage
If you wish to use the 851N as a Digital Pre-Amplifier we have a few tips to prevent damage or confusion regarding your system.
DPA mode is NOT enabled upon initial set-up of the 851N and as such must be enabled before connecting to a power amplifier. Failure to do so may result in speaker damage.
When you attempt to enable DPA Mode, we would advise switching this feature on before connecting the 851N to your Power Amplifier. If you have already connected the devices, please ensure there is no audio playing through your system.
Please check the volume of the 851N is initially set to a low level every time you use the unit, before switching the Power Amplifier on.
If at any point you wish to perform a factory reset on your unit, this will then disable Digital Pre-Amp Mode. This will, therefore, need to be switched back on before using your system.
We would advise checking DPA is enabled after every firmware update as a precaution.
If at any point you wish to connect an analogue device such as a turntable to your system, this will not be possible directly as there are no analogue inputs within the 851N. You may use an Analogue-to-Digital converter although this can reduce the quality of the audio. This is because the signal will later need to be converted back to analogue to be sent to your speakers and the conversion can add audio distortion.
When is Digital Pre-Amp Mode unnecessary?
DPA Mode is unnecessary when connecting to an Integrated Amplifier as this unit also has a Pre-Amplifier included.
If using a traditional external Pre-Amp, DPA will also be unnecessary for the same reason as above.
You may enable DPA Mode in both of these instances if you wish, although this will then ensure that your system has two separate, active volume controls which may be unwarranted.