Elektor Electronics Magazine DAC2000 Article Review

In November 1999, Elektor Electronics magazine released a series articles about the building process of their state of the art multibit DAC using PCM1704.

They named it DAC2000.

This is quite spectacular because at that time, almost everything named with 2000. It is the new millennium and if you lived at that era you can feel the hype that everyone are excited to welcoming the year 2000.

But how good is the DAC2000?

We are two decades ahead but why I still digging out this ancient vintage multibit DAC article?

Seriously?!

The diagram of this DAC200 is tells everything about this DAC configuration.

Starting with the digital receiver, this is a common DAC implementation using CS8414 as a digital receiver for SPDIF or optical/Toslink connection. The CS8414 is capable to decode the digital signal up to 24 bit 96 kHz in I2s output. Although the CS8414 has it's own clock generator, but in this DAC2000, there is an additional reference/external clock circuitry. Probably for better clock performance.

Then on the digital filter/oversampling section is using DF1704 that made specifically for the PCM1704 DAC. This DF1704 is I2s input and capable to process 24 bit of word length data output.

Of course the DAC is using PCM1704. One IC per channel. This is state of the art multibit DAC, the latest vintage multibit DAC that capable up to 24 bit data process. PCM1704 internally using dual R2R DAC section in balanced configuration to improve the overall DAC performance.

The analog stages which are the current-to-voltage converter (IV stages) and the third pole low pass filter are all using OPA627 high performance op-amps. There are two option LPF section which depends on the digital receiver signal. One for the standard resolution 44.1 and 48 kHz and the other is for the higher resolution 88.2 and 96 kHz sampling rate.

The power supply in this DAC2000 is a common differential voltage using several 5 volt and 12 volt fixed regulators.

The rest of the diagram block such as hardware control and sampling frequency display can be ignored since they can configure manually and not relate to the main DAC function, except if the function of the mute control and LPF slope selection based on the sampling rate frequency are required.

Now let's see the complete schematic of DAC2000.

This DAC2000 schematic looks complicated because the present of the hardware control. If they are configure manually, especially for CS8412 and DF1704, the overall schematic become simple and easy to understand.

Actually this DAC2000 articles are comes in three parts. The first and the second parts are mostly talking about the DAC working principles. The third part are more focus on the components list, PCB design and measurement.

In general, I like the DAC2000 idea. This is a very common PCM1704 DAC implementation that guarantee to sound good.

Something that different is at the analog stages. This DAC2000 using the third pole LPF which is new for me. The reason is when a DAC in the oversampling configuration, the number of LPF pole doesn't require this much. So in my experience when build an oversampling DAC, using second pole LPF is more than enough to remove most of digital images from the analog output.

So I guess after two decades since this DAC2000 published, many audiophile still wondering how good it is. No wonder because the Delta Sigma DAC are already in their mature performance and then the popularity of the vintage multibit DAC slowly came back again.

This article might be a remedy for someone who looking to this DAC2000 specifically.

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