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Mark Levinson No 40 HD Media Console (Surround Sound and Video Processor)

Part II

July, 2007

Sumit Chawla

 

Here is the inside of the video processor.

The digital-to-analog conversion is handled by Analog Devices AD1853 DACs. These 24-bit, 192 kHz multi-bit Sigma/Delta converters are used in a dual differential configuration for the eight main output channels, meaning that each of the eight channels is fully balanced. The DACs used for the remote zones are not specified; however, they are stated to be 24-bit, 192 kHz capable. To maintain the full resolution of these DACs, a digitally controlled analog volume control is used.

All digital audio signals pass through a jitter rejection stage where incoming data are buffered and re-clocked. FIFO stands for first-in, first-out which is needed to maintain the causal relationship of the incoming data. The data re-clocking ensures that the data are leaving the FIFO at a constant rate. ML calls their implementation an "Intelligent FIFO".

I/Os

The back panel of the No 40 provides a look which is different from most processors that are out there. The connectors are neatly arranged either vertically or horizontally depending on the orientation of the card. The expanded real-estate which comes from having two-chassis also allows good spacing between the connectors. This is unlike most processors where you get a busy look with tight spacing between the connectors. Most processors are not hardware upgradeable, so they need to build in the maximum number of connectors that anyone may need rather than making the number of connectors configurable via upgrades.

Here are the rear panels of the audio processor (top photo) and the video processor (lower photo). You can click on the photos to see larger, more detailed versions.

As delivered, the audio processor has numerous filled card slots as well as three empty card slots for additional future upgrades. Some of the cards include:

A pair of two-channel balanced analog inputs.

Three pairs of single-ended analog inputs (there are 2 cards with this configuration).

Two AES/EBU connections and one S/PDIF connection via a BNC connector.
Digital audio via three RCA and two Toslink inputs.

HDMI inputs and outputs.

A pair of single ended analog outputs and a digital output (there are 2 cards with this configuration: one for each of two remote zones).

Generally speaking, there is no fixed mapping of a card to any given slot. A card simply registers the I/Os it provides for the slot its gets placed in. ML does, however, have a default configuration that they offer where the cards occupy fixed slot locations.

The audio and video processors communicate with each other through a custom interface. The hookup for this interface is provided on yet another card. There is a second connector on this card which is unused at this time. The four SHARC DSP chips which crunch through the audio data are housed on this card.

The cards which are oriented horizontally are located at the bottom of the panel. These slots are named with letters instead of numerals. A pair of balanced and single-ended analog outputs is located on a total of four cards. These cards also provide digital to analog conversion and volume control for their respective channels. Presumably the DACs can be changed by swapping out these cards.

The video processor provides an assortment of analog video inputs and outputs. The varieties of connectors that it offers are: Composite, S-Video, and Component. There is one card offering three composite video inputs. Two cards each provide three S-Video inputs. Three cards each offer a component video input using BNC connectors. The two remote zones offer only composite and S-Video outputs.

The video output for the main zone is offered through composite, S-Video, and component connectors. The component connectors serve double duty, as they can be configured to output RGB plus sync there is an additional connector for sync. A monitor output provides hookup with an external display device. I connected this output to an external LCD which provided a better viewing angle than the front LCD from my listening location.

Go to Part III.

Copyright 2007 Secrets of Home Theater & High Fidelity

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