The DAC from Ipanema

This project shows a way to connect a comercially available SPDIF receiver to the TDA1543 DAC.

Views of DAC

This little and unexpensive 'SPDIF to Analog' DAC offered on the web under different branding, contains the CS8416 SPDIF digital audio receiver and the CS4344 DAC on a double layered PCB. Component layout and wiring seem -as far as I can assess it- to follow the recommendations for low jitter given in the CS8416 datasheet.

The CS8416 is wired for hardware mode operation and I2S interface. The analog part of the DAC is wired very much like the datasheet's recomendation. Its output is fed via a simple RC filter to the RCA connector.

In my system, the sound has something appealing to it, good stage and instrument location but is not what I would call audiophile. Admitedly too high an expectation for the price. Still, the 'CIRRUS LOGIC' chips have a good reputation so I blamed it on the RC filter and put it aside with the idea of maybe connecting the DAC directly to a tube output stage at some later date...
View of DAC PCB

Weeks later, I came across a forgotten TDA1543 neatly packed in a corner in my shack. It has an I2S interface so I decided to try to marry it to the cheap DAC. The price to pay: no oversamplig (maybe a bliss) and goodbye 24bit and higher bitrates.

The picture shows the necessary modifications. The RCA and the DC input jack were removed from the PCB for better access to the I2S on the CS8416.
The other IC is a multiple operational amp. probably linked to the optical SPDIF input. The CS4344 is on the bottom side of the PCB and thus not visible here.

+6V from an adjustable LM317 regulator supplies the TDA1543 and -connected to the input of the +3V regulator of the PCB- also the rest of the circuit. Since the CS4344 I2S interface required +3V and the TDA1543 requires +5V, a separate +5V is needed to provide the correct voltage on the I2S towards the TDA1543. For this purpose it is necessary to remove the SMD component that was originally at the red framed position enclosing the +5V connection.
This component (either a jumper or a coil) was part of the +3V supply filter for the I2S interface. Removing it leaves the +3V supply end open. At the other end the +5V can be connected. This way also part of the I2S supply filter (C35, C11 and C36) can be reused.

Build on a one sided copper clad PCB to hold it together, this 'quick and dirty' setup provides the CS8416 with a good filtered power supply.

Along with the TDA1543 working in non oversampling mode rewards with a great sonic result. It swings so cool and sways so gentle that everyone that hears it goes aaaaaah...
Component values around the TDA1543 have been 'stolen' from Doede Douma's Project DDDAC 1543MK2.

Jan. 14. 2012, Carlos Durandal
inserted by FC2 system