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buffalo II multi channels capabilites for multi amplification with digital active crossover
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Joined: 11/4/2010(UTC)
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Hi,
I am interested in the multi channels capabilities of the sabre dac.
In an old post, you told it should be possible to use the channels and program the filters for multi amplification with digital active crossovers without a need for external DSP.
How is it possible with the buffalo II board ?
Since there are 2 balanced outputs, does it mean that without board modification and just a little of programming (using femto or arduino), is it possible to have four outputs ?
That will means with one buffalo board we can go at least to bi amplification quite easily (in single ended only).
We will need two boards for tri amplification and three boards for balanced tri amplification.
Thanks for your help !
Bye
Lwi
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Rank: Member
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Actually, to be more precise, with two boards we can go quadri amplification in single ended.
If it is possible ! :)
How can we connect three boards digitally (spdif and i2s) ?
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Rank: Member
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Joined: 11/9/2007(UTC)
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The DAC outputs are hardwired for stereo. The Sabre chip only has two possible I2C addresses, so without some surgery or I2C address multiplexing, 4 channel is the max with two boards. Whether single ended or balanced, you are still restricted to 2 channels per board. Then you can easily program the filters provided you can come up with the coefficients for them.
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There are not enough coefficients to use them as a crossover.
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Rank: Member
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Ok, that seems a bit more complicated.
Now, if the crossover is done by software, what is necessary to configure two buffalo boards in four channels ?
Something in parallel, how to root two buffalo boards for I2S ?
For example, it is possible to branch a hiface usb -> I2S to 2 buffalo boards with I2S in parallel ?
In this case is it the same in order to have 4 channels with 2 boards by I2S and spdif ?
Thanks for your help.
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As Brian was saying, there insufficient taps in the ES9018 for filters that are very useful in the audio range.
As for I2C, you could control up to 2 DACs each with 2 channels each per I2C interface. You can do as many chanels of I2C as your controller will allow. It would be quite easy to control 8 or more channels.
Yes you can simply route two sets of wire from your I2S source.
For SPDIF when using two DACs you wire one DAC for SPDIF input with SPDIF switch closed(on) and wire your source to SPDIF input and GND. You wire the D1 and GND from the first DAC to D1 and GND on the second and leave the SPDIF switch open on the second DAC. This way the consumer level SPDIF signal is properly terminated and you will have one comparator driving D1 on both DACs and they will both be in sync.
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Rank: Member
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Joined: 11/4/2010(UTC)
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Now if I have two boards connected to one spdif output as explained, what is needed to handle four channels on spdif ?
As I said, we can do the crossover by software on the computer, then we have four channels on spdif with an interface like hiface, or if we hack the hiface we can have four channels on I2S, since I2S is paralleled for the two buffalo boards, how to configure everything ? How to know which channel goes where ?
I hope I am clear, the idea is that we have four channels as spdif or I2S and we want to get it out from the two buffalos.
At least that will enable stereo bi amplification.
For tri amplification we will need three boards. But I have seen that it is difficult to have three I2S in parallel, is it a problem for spdif ? Is the configuration for three buffalos the same as for two, leaving the middle one closed (on) and the last one open (to terminate the signal) ?
Thanks a lot for your help and your great work !
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Twisted Pear Audio Support
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buffalo II multi channels capabilites for multi amplification with digital active crossover
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