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Dear Russ/Brian,
my mux in the subject is connected I2S to Buffalo II, and it works perfectly, included 24/192.
The mux passthroug S/PDIF out is connected to another Buffalo II, set on consumer S/PDIF input, with a short coax cable. It works perfectly till 176 but do not lock at 192Khz (led flashs very fast). This second Buffalo II board has no problem, tested with other spdif input at 192 works perfectly.
The power supply to the mux is 5,2 volt and will not decrease at 192 (measured).
WHat can it be?
Thanks in advance,
Andrea
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The S/PDIF passthrough is TTL-level, not consumer-level, so for the B-II, turn off the S/PDIF switch.
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Or use a cap and voltage divider to get it closer to consumer level. 100nf then 221R series with 100R to GND will work fine.
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Its probably easier to use Brian's approach. You just want to be careful about running longish wires with TTL level signals.
if the route is long I would use the voltage divider and go into the consumer SPDIF input. If the route is short - use Brian's approach straight into D1.
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Dear Brian/Russ,
I just would like to ask:
What about the possibility to modify C5 R3 and R2 (or only R3 and R2) before the coupling transformer (same of the inputs) to get an SPDIF consumer out (and avoid too many components). Which value should they have?
Thank you,
Andrea
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Ah yes, thanks for reminding me. Yes that network is already there and should be providing consumer level output. No need to change anything.
Obviously its been a while since I looked ta that circuit. :)
If you are still having trouble I am not sure what might be going on. It could be wiring. or it could be something about CS8416 itself. I would check the datasheet and see if there is any limitation on SPDIF pass-through.
Cheers!
Russ
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Dear Russ,
that's why I was a bit doubtly...
I didn't try to input D1 yet (I am away from home for some days) but I was wondering if - instead - the signal at 192Khz becomes too low with that voltage divider + a coupling transformer, even for consumer spdif...?
Some useful information:
- everything works well till 176; at 192 the buffalo "lock" led flashes very fast but never locks.
- the mux passthrough out is linked to the buffalo spdif in with a short coax cable of around 15 cm. I tried to replace the cable, but no changes.
- while injecting 192 signals, I measured the power supply of the buffalo and of the mux, they remains stable as it is at 176.
I kindly ask for help :)
Thank you,
Andrea
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One thing that may be worth trying is removing the transformer from the MUX output. It could be that that output does not have enough drive for the transformer at that speed.
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Dear Russ, Brian, the 192Khz issue is solved: - transformer removed at the mux output - left on place R3=300Ohm (series) + R2=100Ohm (parallel). Is that ok the voltage divider? Which are the practical disadvantages for having that transformer removed ? Thanks in advance, Andrea Edited by user Wednesday, July 3, 2013 5:00:18 PM(UTC)
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You lose galvanic isolation between the MUX and DAC, but that's not a big deal. You still have it between your source and the MUX.
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