Usually this would be done after the digital input controller, like the Cirrus input parts, and then have multiple DAC's use the same I2S digital data signals.
I guess we need more information on what you're trying to accomplish: 2 Dac's in the same room or seperate rooms?
You're going to want to avoid supplying a common SPDIF signal to multiple DAC's in the same system. That's frought with all kinds of grounding, impeedance, and signal timing issues.
-David
I guess we need more information on what you're trying to accomplish: 2 Dac's in the same room or seperate rooms?
You're going to want to avoid supplying a common SPDIF signal to multiple DAC's in the same system. That's frought with all kinds of grounding, impeedance, and signal timing issues.
-David
Thanks dw8083
I was writing details about my setup and realized that I wan't be able to control volume vith 2 dac's.
this is my current setup
-------------------------------------------------------behringer equalizer(2nd dac) -- amp -- woofer
cd player --> monica2 dac -- preamp --- <
-----------------------------------------------------2nd amp --- capacitor --- tweeter
I just wanted to bypass monica2 dac -- preamp section for woofer
I was writing details about my setup and realized that I wan't be able to control volume vith 2 dac's.
this is my current setup
-------------------------------------------------------behringer equalizer(2nd dac) -- amp -- woofer
cd player --> monica2 dac -- preamp --- <
-----------------------------------------------------2nd amp --- capacitor --- tweeter
I just wanted to bypass monica2 dac -- preamp section for woofer
MisterTwister said:
There is a device designed for this task. It is called Digital Audio Distribution Amplifier (DA). Typically, it will distribute a single input to around 8 or more outputs. Unfortunately, they aren't inexpensive as they tend to do more than just distribute. Fortunately, you can make a simplified version with a little 74 series logic.
There is no problem with two DACs sharing the same S/PDIF connection. I do it routinely. In fact, splitting at the S/PDIF level to feed two external DACs is preferable to splitting the output of the DIR.
S/PDIF was designed to interface external boxes. The DIR uses a differential receiver and quality DACs usually have input transformers, which provide isolation and fewer ground problems. CDPs often have differential transmitters and higher end units have output transformers. Transmitters, receivers, and connecting cable all have the same impendence, thus eliminating reflections. The data encoding is biphase, which uses state transitions rather than signal levels to differentiate ones and zeros. The word clock can be derived from the timing of the unique sub-frame preambles, which is very accurate and jitter-free. (It is a mistake to derive any clocks from the biphase data stream, other than preambles, because, by definition, it is irregular.)
Other benefits include parity checking on sample data giving the DIR the ability to recognize data errors and repeat the last good sample or interpolate through the error. Another is the transmission of the state information, including the emphasis bit. To this day, many labels are still producing CDs with emphasis. Finally, S/PDIF allows you to mix and match DAC species. At the moment I have two DACs connected to my lab PC with S/PDIF. One is a 16-bit, I2S NOS and the other is a 24-bit, right-justified delta-sigma.
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