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Old 10th December 2018, 05:50 AM   #821
syracuze is offline syracuze  United Kingdom
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Join Date: Jan 2018
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Introducing the Buffalo III-SE-Pro 9028/9038
Default 128 * Fs gear clock

Quote:
Originally Posted by Russ White View Post
Hey guys - I have not had much time to play with pure-sync until this weekend. I am working on it today and have a few observations:

Importantly - we must set a clock gearing ratio to play DSD (and to get optimal PCM). The gear ratio will entirely depend on the frequency of your master clock. The key is you need to gear the clock to 128FS. This has some implications for hermes/cronus.

The key here is we need to use some port expander positions to indicate what gearing to use. This could be automated from certain sources like the amanero - but not (currently - at least ideally) via hermes/cronus because you would lose isolation. So the best short term solution would be to set the gearing manually (via the DIP/Panel switches or controller) and then stick to a single sample rate - possibly resample all content at the player.

Open to suggestions
Hi Russ,

I was reading through your previous posts; I believe, current version of sync firmware is mentioned in post 663/page 61 of this thread.

How does this Firmware respond if one feeds in multiples of 128 * Fs; e.g. 256 * Fs, 512 * Fs?

Thanks
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Old 10th December 2018, 06:48 AM   #822
twluke is offline twluke  Japan
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Introducing the Buffalo III-SE-Pro 9028/9038
Quote:
Originally Posted by Russ White View Post
-snip-
The key here is we need to use some port expander positions to indicate what gearing to use. This could be automated from certain sources like the amanero - but not (currently - at least ideally) via hermes/cronus because you would lose isolation. So the best short term solution would be to set the gearing manually (via the DIP/Panel switches or controller) and then stick to a single sample rate - possibly resample all content at the player.

Open to suggestions
How about providing a daughter board to generate MCLK from BCLK using a multiplier from such an ICS? If this is possible, the MCLK becomes only dependent on the source frequency and it can be always set to fulfill 128fs for pure sync mode. This will not break isolation.

Regards,
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Old 10th December 2018, 09:10 AM   #823
Dimdim is offline Dimdim  Greece
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Introducing the Buffalo III-SE-Pro 9028/9038
Quote:
Originally Posted by Russ White View Post
Hey guys - I have not had much time to play with pure-sync until this weekend. I am working on it today and have a few observations:

Importantly - we must set a clock gearing ratio to play DSD (and to get optimal PCM). The gear ratio will entirely depend on the frequency of your master clock. The key is you need to gear the clock to 128FS. This has some implications for hermes/cronus.

The key here is we need to use some port expander positions to indicate what gearing to use. This could be automated from certain sources like the amanero - but not (currently - at least ideally) via hermes/cronus because you would lose isolation. So the best short term solution would be to set the gearing manually (via the DIP/Panel switches or controller) and then stick to a single sample rate - possibly resample all content at the player.

Open to suggestions
So, in order to get the absolute best results for Red Book audio we will need to use an MCLK of 5.644,8 MHz?
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Old 10th December 2018, 02:32 PM   #824
twluke is offline twluke  Japan
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Introducing the Buffalo III-SE-Pro 9028/9038
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Originally Posted by Dimdim View Post
So, in order to get the absolute best results for Red Book audio we will need to use an MCLK of 5.644,8 MHz?
If based on the math of 128fs, that will be correct.

Since the introduction of the pure sync firmware in April, I've been enjoying this pure sync mode on my 9038pro and 9028pro DACs (the latter in dual-mono pure sync) from TPA and can say that one particular rate of MCLK fulfilling 128fs can cover the source of 64fs for ordinary use: meaning that a 11.2MHz MCLK may cover the source requiring 5.6MHz MCLK for pure sync but you will soon find the SQ is not the same and slightly compromised.

The current firmware for WithDisplay allows to change the clock gear to the half rate using the basic function of ES9038/9028 but I would say that you can not avoid some degradation of the SQ with this setting, as long as based on my personal experience.

Regards,
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Old 10th December 2018, 02:57 PM   #825
Dimdim is offline Dimdim  Greece
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Introducing the Buffalo III-SE-Pro 9028/9038
The 9028/38Pro chips support clock gearing settings of /2, /4, /8 so even a 45.1584MHz clock could be used as clock for a 44.1K SR in 128fs with no problem.

But you are saying that using the clock gearing degrades SQ?

So, using a "real" 5.6MHz clock is the better sounding solution?
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Old 10th December 2018, 03:41 PM   #826
twluke is offline twluke  Japan
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Introducing the Buffalo III-SE-Pro 9028/9038
Quote:
Originally Posted by Dimdim View Post
The 9028/38Pro chips support clock gearing settings of /2, /4, /8 so even a 45.1584MHz clock could be used as clock for a 44.1K SR in 128fs with no problem.

But you are saying that using the clock gearing degrades SQ?

So, using a "real" 5.6MHz clock is the better sounding solution?
At least, as long as the current beta firmware enabling gearing function by Russ is concerned, my answer would be yes, though it may be probably dependent on the configuration (I have no data sheet now).

Regards,
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Old 10th December 2018, 03:52 PM   #827
Dimdim is offline Dimdim  Greece
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Introducing the Buffalo III-SE-Pro 9028/9038
I'm pretty sure Russ' firmware is just fine. I don't think anyone else can do better.

Besides, the datasheets describe clock gearing as a "power saving feature", so......
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Old 10th December 2018, 04:07 PM   #828
barrows is offline barrows
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Russ: My approach is already to re-sample everything to DSD 256 in the software player, so this solution is perfect for me. I am using Hermes/Amanero/Cronus with a single 45.1584 XO (with a jumper cable the other clock position). I really like feeding the ESS DSD 256 and feel no need to be compatible with other rates at this point.
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Old 10th December 2018, 07:24 PM   #829
pawlus is offline pawlus  Canada
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Join Date: Oct 2008
Location: Vancouver BC
Quote:
Originally Posted by Russ White View Post
Hey guys - I have not had much time to play with pure-sync until this weekend. I am working on it today and have a few observations:

Importantly - we must set a clock gearing ratio to play DSD (and to get optimal PCM). The gear ratio will entirely depend on the frequency of your master clock. The key is you need to gear the clock to 128FS. This has some implications for hermes/cronus.

The key here is we need to use some port expander positions to indicate what gearing to use. This could be automated from certain sources like the amanero - but not (currently - at least ideally) via hermes/cronus because you would lose isolation. So the best short term solution would be to set the gearing manually (via the DIP/Panel switches or controller) and then stick to a single sample rate - possibly resample all content at the player.

Open to suggestions
Simpler is better so I'd vote for the DIP switch solution. Like barrows, I'm resampling everything to DSD256 with the current beta firmware except native DSD files. I can resample those as well if necessary. Really like the sound with the current sync firmware. Thanks for the effort on this.
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Old 10th December 2018, 07:30 PM   #830
itsikhefez is offline itsikhefez  United States
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Introducing the Buffalo III-SE-Pro 9028/9038
This discussion is very interesting but unfortunately I seem to have some significant knowledge gaps on this topic and is getting confusing.
For purely Redbook material, which would be the "best" configuration for Chronus/Hermes/Amanero -> 9038 ?
I'm using the default Amanero firmware, with the 45/49 pair.
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