Upgrades for the Wadia 27i - CD and New Formats

Wadia has been manufacturing modular upgradeable digital audio components for over ten years. The Wadia 27i is the most modular and upgradeable product in Wadia history. There are two classes of upgrades that could be introduced for the Wadia 27i. For one, the Wadia 27i can be upgraded to take advantage of new Wadia-developed technology that will improve performance regardless of changes to the format. In fact several new such topologies are being developed at Wadia that may eventually be incorporated into future Wadia 27i upgrades. In addition, should a new standard become established, Wadia 27i’s flexible design means that it could be upgraded to decode them more easily, and for higher performance, than other product currently on the market.

Modularity in the Wadia 27i

 There are many design features that contribute to the ease and cost effectiveness with which the Wadia 27i can be upgraded: 

Multiple circuit boards

The Wadia 27i has six separate circuit boards, one for each discrete function: digital input and output circuitry, digital-to-analog conversion, digital signal processing, display/control, and power supply. This allows specific parts of the unit to be upgraded at the lowest possible cost. For example, the input board could be changed to accommodate new input or decoding hardware. 

Software re-programming

The main program chip in the Wadia 27i holds the operating software for the major system components. By changing this chip, the unit can be reconfigured in a wide variety of ways. This chip holds the instructions for three circuit sections:

Control Microprocessor: The display, input and output circuitry, and remote functions are controlled by a single microprocessor. Changing the program that controls the microprocessor can modify any of these functions.

Software-Based Digital-Signal Processing: Wadia’s patented DigiMaster 1.2 filtering system in the Wadia 27i currently operates at 64-times re-sampling with 24-bit resolution. This system can easily be upgraded to operate at 96 KHz or 192 KHz, simply by changing the main program chip.

 Field-Programmable Gate Arrays: Every Wadia product utilizes these re-programmable devices for input circuitry, clocking, and data handling. Changing the main program chip allows any of this circuitry to be re-configured. 

Modular rear panel

Many types of upgrades could require new rear panel connectors. The rear panel of the Wadia 27i features a sheet-metal insert that an be changed at far lower cost than replacing or re-machining the rear panel.

Upgrades to Decode High-Resolution Signals

Decoding PCM Signals (96 or 192 kHz, 24-bit signals)

Because of the modular design and high-speed processing that the Wadia 27i DigiMaster system already uses to extract maximum performance from the CD format, upgrades to decode the proposed high resolution format are truly simple.

The Wadia 27i currently accepts 24-bit signals from all inputs. The DigiMaster filter system interpolates additional samples to a maximum sample rate of 3.072 MHz, at 24-bit resolution. This data rate is faster than is required for any of the proposed formats.

When processing 48 kHz signal, the Wadia 27i DigiMaster system performs 64-times over-sampling interpolation, creating 63 new samples for each original sample, producing a effective 3.072 Mhz sample rate. Similarly, 44.1 kHz input results in a 2.822 Mhz rate. Over years of research, Wadia has determined that these are the optimum data rates for extracting maximum performance from today’s digital-to-analog converter chips.

With a 96 kHz signal, the system would simply perform one less interpolation, thereby executing 32-times over-sampling which results in the same 3.072 MHz sample rate. Similarly, for 192 kHz the DigiMaster system would perform 16-times over-sampling, resulting in the same 3.072 MHz sample rate.

By comparison, first-generation 96 kHz digital-to-analog converters perform 8-time over-sampling at best. The resulting data rate is slower than what the Wadia 27i currently generates. This is not meant to imply that a Wadia 27i processing 44.1 kHz data will outperform a 96 kHz system, only that the Wadia 27i is already capable of processing high-resolution signals at a higher level of quality than any 96 kHz unit on the market.

Decoding DSD Signals

With the Sony/Phillips DSD system, Wadia would add a "piggy-back" circuit board to the current DSP board, which would convert the Wadia 27i to a DSD-to-analog converter. With such an upgrade, all the processing power, conversion accuracy, and high quality analog circuitry already contained in the Wadia 27i would be brought to bear on performing the highest quality DSD-to-Analog conversion possible.

Receiving and Transmitting New Formats

So far, the only available format for transmitting high resolution digital audio signals from a transport to a digital-to-analog converter is the AES/EBU or SPDIF system (or an AES stream on glass fiber). To upgrade a Wadia 27i to accept high resolution signals on using these connections requires changing only the receiver chip located on the Wadia 27i DSP circuit board. This is a simple and inexpensive upgrade.

However, it is unlikely that the SPDIF or AES/EBU transmission formats will become an accepted standard for transmission of high resolution formats for either DVD Audio or Sony/Phillips’ SACD system. Many software companies are indicating that to prevent illegal copying of discs, high resolution data must not be available via unencrypted outputs like SPDIF or AES/EBU.

It is more likely that high resolution audio formats will be transmitted via FireWire (IEEE1394) or some other encrypted transmission system. Such a system would require new electronics to receive and decrypt the signal, and a new connector to accept the new format. For products that are not extremely flexible and modular in design, adding this type of capability will not be cost effective. Because no format has yet to be approved for this purpose, it is impossible to claim, as some manufacturers have, that any current transport or digital-to-analog converter is compatible with the new format.

The Wadia 27i, however, can be readily upgraded to FireWire or other transmission systems. First, the input circuit board is a separate modular board that can easily be replaced. In addition, the rear panel has a sheet-aluminum insert than can be inexpensively replaced with one that accommodates the new connector.

The Wadia 27i — 96 kHz Upgrade

Wadia recently demonstrated an upgrade to the Wadia 27i that enables it to receive and decode 96 kHz signals via SPDIF, AES/EBU, or ST glass fiber inputs. This upgrade requires changing only two chips: the software ROM that holds the DSP code, and the input receiver chip, both located on the digital signal processing board.

With this upgrade installed, the Wadia 27i decodes 96 Khz signals and performs 32-times interpolated over sampling. With true 22-bit resolution, the Wadia 27i has the highest resolution of any digital-to-analog converter available. As such it can be compared favorably to any other 96 kHz-capable converter on the market.

This upgrade could be introduced to the market at a very low cost. However, because it does not support what will most likely be the new transmission formats, Wadia will not ask our customers to spend their money on a temporary fix. When the format issues are resolved, Wadia will introduce upgrades that will allow the Wadia 27i to make the best of these new formats.

In the meantime, the Wadia 27i continues to set the standard for extracting maximum musical performance from today’s recordings, while standing poised to accept new technology as it becomes available.