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Old 29th February 2012, 03:11 PM   #1021
Bunpei is offline Bunpei  Japan
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Quote:
Originally Posted by exa065 View Post
2.5 ns is horrible
I believe that your e18 DAC might have adapted a synchronous master clocking mechanism so that you may take full advantage of the low jitter nature of signals output from your own high performance built-in USB-I2S interface board.
Otherwise, By using a conventional asynchronous fixed-frequency master clock of 80 or 100 MHz which brings unavoidable and inherent clock-tick derived jitter of 10 ns, your precious low jitter I2S signals will be degradated severely in the DAC chip.

One more my opinion. Direct signals originated from the inside of XMOS do not necessarily mean the I2S signals output from the USB interface board. Some skillful designer may use a direct or divided signal forked from an audio frequency dedicated external oscillator of low phase noise for LRCLK, BCLK or MCLK in I2S set.
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Old 29th February 2012, 04:32 PM   #1022
exa065 is offline exa065  Canada
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Quote:
Originally Posted by Bunpei View Post
Otherwise, By using a conventional asynchronous fixed-frequency master clock of 80 or 100 MHz which brings unavoidable and inherent clock-tick derived jitter of 10 ns, your precious low jitter I2S signals will be degradated severely in the DAC chip.
Bunpei, are you saying that the ES9018 patented internal jitter-elimination processing is causing 10ns jitter?

Are you sure that you can draw parallels between the careless general purpose fractional division that takes place inside XMOS, and mechanism inside ES9018 that is actually designed to fight jitter?

Can you provide some evidence for this claim?

Quote:
Originally Posted by Bunpei View Post
One more my opinion. Direct signals originated from the inside of XMOS do not necessarily mean the I2S signals output from the USB interface board. Some skillful designer may use a direct or divided signal forked from an audio frequency dedicated external oscillator of low phase noise for LRCLK, BCLK or MCLK in I2S set.
Yes, of course you can generate jitter and then you can deploy measures to cancel it. This is what SP/DIF is all about. My preference is to avoid it at first place.

Do you know who is doing jitter cancelling on xmos-based asynchronous USB to I2S interface? Is it done well? Are there any measurements, and are they backed by blind listening tests?

As you know, I've published measurements, and there is no hint for 10 ns jitter. The lack of jitter is backed by the testimonials of ALL of our users. They say that exaU2I is in a different league compared to the rest.
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Last edited by exa065; 29th February 2012 at 04:48 PM.
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Old 29th February 2012, 04:39 PM   #1023
exa065 is offline exa065  Canada
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I forgot to mention, the exaU2I-BlackDAC measurements are done with l00MHz master clock. These measurements provide indication about the performance that can be achieved with exaU2I-Buffalo DAC in asynchronous mode.
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Last edited by exa065; 29th February 2012 at 04:45 PM.
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Old 1st March 2012, 03:42 PM   #1024
Bunpei is offline Bunpei  Japan
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Quote:
Originally Posted by exa065 View Post
... are you saying that the ES9018 patented internal jitter-elimination processing is causing 10ns jitter?
No. I think their jitter-reduction processing is a kind of stopgap measure of correcting sound intensity values by an interpolation. Route origin is in the clock tick gap between fs domain and DSP domain.
By the way, would you tell me the number of the patent that you indicate?

Quote:
Originally Posted by exa065 View Post
... Are you sure that you can draw parallels between the careless general purpose fractional division that takes place inside XMOS, and mechanism inside ES9018 that is actually designed to fight jitter?
I'm not sure. However, ES9018 seems to have a computer chip-like architecture ( which point I favor much) for me. All events in the DSP-side domain within the chip might be under the control of system clock and they are aligned to a system clock tick.

Quote:
Originally Posted by exa065 View Post
... Can you provide some evidence for this claim?
Yes. However, I don't want to give any adverse effect to this thread of your business. Shall we have further technical discussions on ESS Sabre32 thread?

Quote:
Originally Posted by exa065 View Post
... Yes, of course you can generate jitter and then you can deploy measures to cancel it. This is what SP/DIF is all about. My preference is to avoid it at first place.
I agree with you. Your approach is correct, I think. Your exaU2I can perform very well with such DAC chip, DSD1794, WM8741, AK4399, etc. by employing a conventional synchronous master clocking scheme.

Quote:
Originally Posted by exa065 View Post
... Do you know who is doing jitter cancelling on xmos-based asynchronous USB to I2S interface? Is it done well? Are there any measurements, and are they backed by blind listening tests?
I have no facts on this point. However, I have a prospect of high confidence.

Quote:
Originally Posted by exa065 View Post
... As you know, I've published measurements, and there is no hint for 10 ns jitter. The lack of jitter is backed by the testimonials of ALL of our users. They say that exaU2I is in a different league compared to the rest.
I avoid using the term "jitter" because the term is very ambiguous. If you show a phase noise chart instead, that will make me feel very comfortable.

Last edited by Bunpei; 1st March 2012 at 03:50 PM.
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Old 6th March 2012, 11:16 PM   #1025
exa065 is offline exa065  Canada
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Default The exaSound e18 DXD DAC now supports OS X

The exaSound e18 DXD DAC now supports OS X. We offer two Mac drivers optimized for stereo and multichannel experiences at sampling rates up to 384kHz/32bit. Please check our website - www.exaSound.com.
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Old 8th March 2012, 08:13 AM   #1026
oyvine is offline oyvine  Norway
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Default I2S/Spdif input?

Hi,
the exaU21 and the E18 are output-only devices(?) I have a setup where I use the PC as a digital cross-over for various sources (tv, squeezebox, popcorn hour). Sometimes I even use the pc as the source, but in general I like to keep the screen off when listening to music. I switch from source to source via an external switchbox with a spdif-transformer. I wonder if you have given any thought about including some sort of input(I2s?) to the EXA? It would be great to know that the same bit-perfect drivers was handling the complete digital signal-chain to/from ASIO. I know that this requires some sort of synchronization (reclocking for instance) of the incoming data stream.

regards,
ōyvin Eikeland
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Old 8th March 2012, 01:38 PM   #1027
exa065 is offline exa065  Canada
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Quote:
Originally Posted by oyvine View Post
Hi,
the exaU21 and the E18 are output-only devices(?) I have a setup where I use the PC as a digital cross-over for various sources (tv, squeezebox, popcorn hour). Sometimes I even use the pc as the source, but in general I like to keep the screen off when listening to music. I switch from source to source via an external switchbox with a spdif-transformer. I wonder if you have given any thought about including some sort of input(I2s?) to the EXA? It would be great to know that the same bit-perfect drivers was handling the complete digital signal-chain to/from ASIO. I know that this requires some sort of synchronization (reclocking for instance) of the incoming data stream.

regards,
ōyvin Eikeland
Hi ōyvin, both exaU2I and e18 are output-only devices. Your request is on the wish list.
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Old 8th March 2012, 02:48 PM   #1028
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My situation is similar to oyvine - for my DSP rig I currently use external sources routed into a SRC2496 that is slaved to the worclock output of my audio interface (Steinberg MR816x). this isn't the last word in convenience or ergonomics, but does provide flexibility.
I'm very interested in the E18, but am struggling to feel confident that the 'output only' is going to work in my setup. In particular, we use whole-house sync of our 3 squeezeboxes to play our library as well as streamed XM content, and I'm not entirely sure that I can replicate that even with JRMC.
IMHO a wordclock output would be a valuable addition and would probably be easier than a full audio input, but that assumes that you're using an external SRC and whatever signal chain you're using can use different interfaces for input and output - my current setup using Reaper probably can, but I'm not sure about things like JRMC etc.
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Old 8th March 2012, 03:59 PM   #1029
exa065 is offline exa065  Canada
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Many customers have expressed concerns about the exaU2I shipping cost. We've just introduced a low-cost regular mail service to most overseas destinations. The regular mail small-package service is much cheaper, but unfortunately it is slower. There is no insurance and the shipments cannot be traced.
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Old 14th March 2012, 09:01 PM   #1030
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I'm shure this has been asked before somewhere, but cant find it ... so:

According to diy-guide, i should connect power to exaU2I from DACs DVCC. I use ackodac, that has split DVCC in top ring, and bottum ring: DVCC_T, DVCC_B

- which one to use?
- or just use a separate (superior) supply? (as ackodac will run syncron-mode with clock from exa)
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