Overview of 518

7

 

 

Planning setup of 518

Firstly, the 518 is a product for enthusiasts! We designed it for audio and multimedia enthusiasts, keen listeners and those with enthusiasm for the best sound.

However, 518 is something of a chameleon. What do we mean by that? This is best explained by seeing what it does: 518 fulfils four very different functions in one box.

We have categorised uses (applications) of 518 into four broad headings, as follows:

∙A simple 'preamp' orControl Unit for a purist digital audio system. (Type 0) – see below.

∙A Resolution Enhancement processor in a high-quality audio system. (Type 1) – see the overviews on pages 10 and 49.

∙A Mastering Processor, used in any recording, editing, mastering or dubbing process. (Type 2) – see the overview on page 12.

∙A peri-computer Multimedia Processor. (Type 2) – see the overview on page 12.

What's inside a 518?

D1

D2

D3 Opt

Input Switch

 

 

Twin PLL

 

 

42MHz DSP

 

 

Digital Output

 

Out

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Front Panel

Control

RS232

Computer

Internal block diagram for 518

518 is a 2-channel digital audio computer with four inputs – see the diagram above. The selected input is de-jittered with a proprietary Meridian twin phase-lock-loop that acts as a 'big flywheel' to regulate the audio stream. By using this twin PLL we ensure that the outgoing digital audio has very precise timing allowing the final output device (e.g. DAC) to achieve its maximum sonic potential.1

Following the twin PLL is a fast (42MHz) 24-bit Digital Signal Processor, which runs the user programs in 518. The DSP functions are all controlled by an internal computer which co-ordinates the front-panel keys, remote control sensor and display as well as RS232 control.

All software for 518 – control and DSP is held in a socketed EPROM. This allows the potential of upgrades or new applications being issued later.

Following the DSP is a multistandard digital output.

1For the technically interested, Figure 1 on page 49 shows the performance of the twin PLL.

518 User Guide