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Russ White posted on diyAudio to deanoUK: "If you are willing to do some surgery on the USB Streamer you could easily get that type of solution to work with a single Cronus and a Single Hermes - BBB (repurposed for the Streamer) You would just wire the USBStremer to the appropriate pins on the BBB header. This would get you 8 isolated/reclocked channels all sharing the same cronus master clock. If you need more help let me know." An unsure whether deanoUK proceeded to try to do this himself but I am certainly keen if the offer of help is still there. My initial question is which Rhea crystals should I use? The USBStreamer needs 22/24Mhz but I understand it is recommended to use 45/49Mhz when connecting to the B3 - can the MCLK OUT signal be halved? Edited by user Tuesday, September 22, 2015 8:01:59 AM(UTC)
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Cronus reclocker needs clocks with double frequency of maximum supported frequency.
If you don't want to play files with 352.8/384kHz sampling rate then you can use also 22/24MHz and set divider to 1:1.
In the other case use 44/48MHz and divider 1:2.
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Originally Posted by: miero  Cronus reclocker needs clocks with double frequency of maximum supported frequency.
If you don't want to play files with 352.8/384kHz sampling rate then you can use also 22/24MHz and set divider to 1:1.
In the other case use 44/48MHz and divider 1:2. Sorry, but I don't understand. Even 22/24Mhz frequencies are orders of magnitude greater than 384Khz (i.e.: far greater than double). I was under the impression there was an advantage in using the 45/49Mhz clocks with the B3 as it eliminates the need for it to do any reclocking?
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My second question is how to integrate to the Cronus's clock selection multiplexer to switch between 44.1 and 48Khz time bases.
The only indicator that the USBStreamer provides that can be used to do this switching is its own internal MCLK (which switches between 22/24 Mhz depending upon the input timebase.
Is it possible to trigger Cronus clock selection from this somehow?
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BBB header of Hermes-BBB: P9_24 clock selection switch - drive it low or high to switch the clock (ISOLATED) Hermes header of Cronus: Pin 15 clock selection switch - drive it low or high to switch the clock (NON-ISOLATED) 384000 (fs in Hz) * 2 (stereo) * 32 (bits per channel) = 24576000 (Hz) required Cronus requires double clock frequency to process incomming signal => 49152000 (Hz) clock is required for playing 384kHz Edited by user Wednesday, September 23, 2015 9:31:35 AM(UTC)
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 1 user thanked miero for this useful post.
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Got it! Thanks Miero.
I guess this means I either need an additional circuit to create a high/low clock switch from the native MCLK on the USBStreamer - or else I only use a single clock for 48Khz based feeds.
One more question: Pin 15 clock selection switch - drive it low to switch to which clock? C2 or C3?
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You should use pin P9_24 pin of Hermes-BBB if you are going to connect streamer to Hermes-BBB.
Pull it HIGH for 48k sampling rates.
I'm not sure if there is easy way to play 44k1 on USB streamer. Does it support such rates natively?
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Yes. The USBStreamer natively supports 44.1Khz - but the only way to tell which sampling rate its using is to monitor its own MCLK - which would presumably require a circuit that gives a low output when 44.1Khz and a high output for 48Khz to feed into P9_24 of the Hermes.
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Originally Posted by: Possum Russ White posted on diyAudio to deanoUK:
"If you are willing to do some surgery on the USB Streamer you could easily get that type of solution to work with a single Cronus and a Single Hermes - BBB (repurposed for the Streamer) You would just wire the USBStremer to the appropriate pins on the BBB header. This would get you 8 isolated/reclocked channels all sharing the same cronus master clock. If you need more help let me know."
How do you do that?
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