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Old 18th April 2011, 11:57 PM   #381
rsdio is offline rsdio  United States
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Quote:
Originally Posted by RayCtech View Post
Is this something you have learned, been told or have you experienced it by yourself ?
I do not understand how you can isolate your analog output from the host computer by leaving the USB data lines connected but replacing only the USB power lines. The exaU2I only connects data to the DAC board and already has an external power supply input. There is no need to improve the USB power since it isn't used for the DAC board anyway.

As far as I am concerned, you could just as easily say that replacing the header connector improved the sound, and I wouldn't believe that, either.
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Old 19th April 2011, 12:11 AM   #382
rsdio is offline rsdio  United States
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Originally Posted by qusp View Post
i am talking about some receivers, which i quite clearly mentioned probably did not apply here due to the nature of the device, as some effort has already gone into the supplies and it is not a traditional receiver.
Considering that there are already over three hundred replies in this topic, I think it would be helpful to stick to discussing the exaU2I. If you want to talk about some other receivers, nobody is stopping you from starting a new topic where your concerns can be more directly addressed.

Quote:
some bus powered usb-spdif/i2s receivers do indeed use the ground and 5v power lines along with cable impedance and a resistor network to negotiate what speed is to be used and to make sure there is in fact a device there to send data to, replacing it with another 5v supply will do nothing in this circumstance, it will simply wonder where the device it is still connected to has gone. other ways around it may be found of course, but the above is not it
I do not understand what you are trying to say. "Some receivers" cannot act differently than others. The USB Specifications define a particular way for power and resistor pull-ups to signal Device speed. But this is not an ongoing signal - it only exists during connection and must be removed before data can flow between the host and device because the same data lines are used. Granted, if you replace the USB power with an alternate source, then you have to make sure that you apply power first and then connect data, but USB is designed for power before data.


Quote:
huh..... who are you talking to?
I am talking to anyone who thinks they can improve the exaU2I but futzing around with the digital supplies. The exaU2I already has galvanic isolation and external power for the I2S interface to the DAC. If anyone can prove that noise from the USB power makes it across that protection, then I'm sure they would be able to prove that the USB data itself causes an equal amount of noise. There is no way to sever the data lines, and they carry a higher signal level than the power lines. Unless someone is saying that the isolation chips are flawed, I don't see the point. Where are the measurements? Anyone can make claims that an elaborate sacrifice of chickens made their DAC sound better, but I'd like to see the schematic and an knowledgeable explanation of why it works better.
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Old 19th April 2011, 07:13 AM   #383
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Quote:
Originally Posted by rsdio View Post

I am talking to anyone who thinks they can improve the exaU2I but futzing around with the digital supplies.
Is this something you have learned, been told or have you experienced it by yourself ?

(I understand it may be hard to answer only the question asked, but please at least try)

Last edited by RayCtech; 19th April 2011 at 07:16 AM.
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Old 19th April 2011, 08:08 AM   #384
rsdio is offline rsdio  United States
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Quote:
Originally Posted by RayCtech View Post
Is this something you have learned, been told or have you experienced it by yourself ?

(I understand it may be hard to answer only the question asked, but please at least try)
None of the above. Your multiple choice question falls under the logical fallacy of Plurium Interrogationum.

I am a scientist, not an alchemist. When someone like yourself claims to have made an improvement, I consider it to be subject to the test of the scientific method. First, you have to present at least some theory as to why your improvement works. Second, your improvements need to be duplicated by someone else outside of your 'laboratory.' Basically, your claims are considered false until proven by peer review.

You seem to be challenging me to disprove your claims, which is the opposite of the scientific method.
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Old 19th April 2011, 08:26 AM   #385
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Default Tweaking of the exaU2I part 2 - pictures part 1..

The attached pictures shows the power supply and the JFET regulators..

In this prototype version I implemented the JFET regulators in the simplest / easiest way possible.

When the exaU2I are mounted inside the DAC cabinet there are already a main LifePO4 battery power and a two stage JFET regulator ready for connection of the exaU2I, and one stage JFET regulators will be soldered directly to the exaU2I PCB to avoid the long wires used in the prototype build.
Attached Images
File Type: jpg Power supply.jpg (207.0 KB, 272 views)
File Type: jpg Regs.jpg (173.4 KB, 468 views)
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Old 19th April 2011, 08:37 AM   #386
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Quote:
Originally Posted by rsdio View Post
None of the above. Your multiple choice question falls under the logical fallacy of Plurium Interrogationum.

I am a scientist, not an alchemist. When someone like yourself claims to have made an improvement, I consider it to be subject to the test of the scientific method. First, you have to present at least some theory as to why your improvement works. Second, your improvements need to be duplicated by someone else outside of your 'laboratory.' Basically, your claims are considered false until proven by peer review.

You seem to be challenging me to disprove your claims, which is the opposite of the scientific method.
No - I am NOT challenging you in any other way than to possibly get an answer in regard of your statements are based on your own experience or something you have learned / been told...
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Old 19th April 2011, 08:46 AM   #387
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Default Tweaking of the exaU2I part 2 - pictures part 2..

The pictures shows where the USB power trace from the USB connector are cut, and where the new 5 volt are connected to supply the USB parts.
The quality of the pictures are not the best, but they will have to do.
On the exaU2I there are also two other places I have cut traces.
The PCB trace going from the 5 volt (USB) to the 3.3 and 1.2 volt onboard regulators and the PCB trace close to the 1.2 volt regulator and reconnecting it to be supplied from the 3.3 volt.
Attached Images
File Type: jpg 3.3 and 5volt.jpg (142.0 KB, 263 views)
File Type: jpg USB mod.jpg (81.7 KB, 260 views)
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Old 19th April 2011, 08:53 AM   #388
rsdio is offline rsdio  United States
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Quote:
Originally Posted by RayCtech View Post
No - I am NOT challenging you in any other way than to possibly get an answer in regard of your statements are based on your own experience or something you have learned / been told...
My statements are based on my general experience with electronics design, combined with my experience and research in the world of audio reproduction. I have designed several commercial USB Devices, and have a great deal of experience with live music recording and mastering. In contrast, I know very little about power amplifier design, but at least Papa can explain why his improvements work, and it always make sense based upon the laws of electronics.

In my opinion, it would take a serious amount of theory and experimentation to explain why changing the power supply on one side of an isolated circuit could affect the analog quality on the other side of the isolation. If such magical properties were capable of passing noise across an isolation point, then I do not understand why your power supply is immune. What is better about your isolation? Explain, please.

Also, for all we know, there are noise sources in your test setup which are not present anywhere else, and thus your assurances that your improvements are substantial may not ever be duplicated elsewhere.
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Old 19th April 2011, 09:05 AM   #389
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Quote:
Originally Posted by rsdio View Post
My statements are based on my general experience with electronics design, combined with my experience and research in the world of audio reproduction. I have designed several commercial USB Devices, and have a great deal of experience with live music recording and mastering. In contrast, I know very little about power amplifier design, but at least Papa can explain why his improvements work, and it always make sense based upon the laws of electronics.

In my opinion, it would take a serious amount of theory and experimentation to explain why changing the power supply on one side of an isolated circuit could affect the analog quality on the other side of the isolation. If such magical properties were capable of passing noise across an isolation point, then I do not understand why your power supply is immune. What is better about your isolation? Explain, please.

Also, for all we know, there are noise sources in your test setup which are not present anywhere else, and thus your assurances that your improvements are substantial may not ever be duplicated elsewhere.
Thats why I wrote the following in one of my previous posts:

Quote:
The difference from the standard setup of the exaU2I in audio quality are in my setup as big as day and night, but I also know that in many so called High-End setups there may not be possible to hear any significant differences..
At least it is good to know that you have a commercial angle to this and not DIY...
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Old 19th April 2011, 09:16 AM   #390
NicMac is offline NicMac  Italy
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Quote:
Originally Posted by RayCtech View Post
The difference from the standard setup of the exaU2I in audio quality are in my setup as big as day and night, but I also know that in many so called High-End setups there may not be possible to hear any significant differences..
You certainly succeed in giving the impression that the "standard" exaU2I is of modest quality and that tweaking it like you did is a must. Or that the rest of your system compares to other "high-end" ones like day and night.....
Clearly you think very highly of your system, and are proud of being the first to "publish" a major DIY haul-over of the exaU2I.
To me all this begs for a huge placebo effect that is likely to render your evaluation of the sonic benefits largely unreliable.
But then again I'm just a stupid scientist....
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