exaU2I - Multi-Channel Asynchronous USB to I2S Interface

[qusp]

Originally Posted by Trevor White

I think it is good that someone is doing something different other than the same old run of the mill chinese ebay DAC specials which seem to consume pages and pages of threads on this forum !! Nobody complains about the free plug that they get on those things but here we have a dude who has put together something which obviously has had a lot more effort put into it than the usual run of the mill DAC and then he gets bagged for talking about it

I don't think DIY audio or even audio is going to move ahead if people shun original thinkers

actually i have complained several times about those threads =), including reporting them on occasion, i agree its insidious; at least EXA was upfront with his commercialism, why the thread remained here i'm not sure, especially after its been brought to a head over the last few days, but there was never any deceit on that aspect. i would argue that since the product already was selling before he opened the thread and asked for 'feedback', it should have been there from the first page. oh wait.... i said that on the first page or 2 and then a few pages later and it was insinuated i had ulterior motives of bringing down the product.

on the other stuff, why so dramatic? we only ask that this commercial thread go where all other outright commercial threads go and the appropriate payments be made to the forum like everyone else has to; not banish him. there he can talk about his products and actually have the legitimate right to tell people what should and shouldn't be covered in his sponsored thread. here i would argue, past politeness he doesn't as long as the topic stays on this device and others like it and there are a few popping up around the place now. one I've already mentioned; another i only just found out about, but i won't post a link here.

[regal]

The china PCB's are being modded/tweaked in those threads, basically just used as a PCB to build upon. The schematics are typically posted and ideas roundtabled to mod, building completly different units out of them. Basically they are sold cheaper than the cost of the parts and a single PCB would cost a builder. Audiophiles have been modding store bought amplifiers since the 30's, it is very much DIY spirited..


This is completly different if you have read what is going on in this thread.

[qusp]

not all of them are like that, but you are right mostly. some (the ones i object to) are started by the companies themselves as nothing more than an ad and for sure they are making money, not all, but some use fake components on half baked data sheet designs and the pcbs are mostly about the last one you would want to do any rework on without lifting something.

[qusp]

sorry, i'll try to keep rant focus

[Trevor White]

Originally Posted by regal

The china PCB's are being modded/tweaked in those threads, basically just used as a PCB to build upon. The schematics are typically posted and ideas roundtabled to mod, building completly different units out of them. Basically they are sold cheaper than the cost of the parts and a single PCB would cost a builder. Audiophiles have been modding store bought amplifiers since the 30's, it is very much DIY spirited..


This is completly different if you have read what is going on in this thread.

modded or not you are still giving business to the dude on ebay and he doesn't have to pay a cent to this forum !! Good eh

[regal]

Originally Posted by Trevor White

modded or not you are still giving business to the dude on ebay and he doesn't have to pay a cent to this forum !! Good eh

less business than digikey or hammond or mouser and espcially a pcb house. Are we going to move all hardware posts to the commercial section?

Your not paying for the design with a china PCB DAC just the hardware which is a platform to build from saving you the cost to build a one off PCB.

This much different than some proporetary unit that claims its digital isolators are better than a 4192to pulse to dig receiver. The Exa is a specialized multichannel/active speaker soundcard, great for that application. But the owner is misleading newbies into thinking it is a super low jitter i2s soundcard/computer transport for the buffalo or other stereo dac implementations is a streatch, the cat fell right out of the bag when the PLL PID had to be lossened up to get it to lock.

Not saying all the china pcb discussions are on the up and up but the lengthy ones where a completly different design is modified around the PCB are.

Here what you see is what you get, the owner defends his design at length and claims modding is wrong and unnecissary, this isn;t the diy spirit, it is a commercial design probably with a patent application.

[Trevor White]

Originally Posted by regal

less business than digikey or hammond or mouser and espcially a pcb house. Are we going to move all hardware posts to the commercial section?

Your not paying for the design with a china PCB DAC just the hardware which is a platform to build from saving you the cost to build a one off PCB.

This much different than some proporetary unit that claims its digital isolators are better than a 4192to pulse to dig receiver. The Exa is a specialized multichannel/active speaker soundcard, great for that application. But the owner is misleading newbies into thinking it is a super low jitter i2s soundcard/computer transport for the buffalo or other stereo dac implementations is a streatch, the cat fell right out of the bag when the PLL PID had to be lossened up to get it to lock.

Not saying all the china pcb discussions are on the up and up but the lengthy ones where a completly different design is modified around the PCB are.

Here what you see is what you get, the owner defends his design at length and claims modding is wrong and unnecissary, this isn;t the diy spirit, it is a commercial design probably with a patent application.

The only difference between Exa and the dude on ebay is that the dude on ebay is getting a free kick whilst exa is forced into another section which is less relevant than this and now he has to pay for it. Doesn't make sense does it ??

If Exa is misleading people then why not debate it with him instead of moving the debate into a less relevant section that less people look at ??

I look at forums like avsforum.com and they have many vendor specific threads mixed in with other general query type threads. It's really no big deal to organize it like that. I don't go looking into the commercial specific threads looking for stuff on digital line level because I come here for that. Had exa been in that section I would never have known what it is that they do simply because I don't usually bother looking there, but I would certainly know all about the ebay dude from this section

[regal]

I don't know, typical guy comes to this forum spends $50 on a near datsheet DAC PCB from ebay and mods away with the group, that's DIY.

What is DIY about the EXA? The price we are paying for software and firmaware programming, the hardware certainly doesn't cost what he is asking. Is the software and firmware being modded by the group? Is it shared? Is it held secret?


I wish EXA the best, but its funny you mention the AVS board, much more appropriate peddling spot.

I'll get off my soap box, time to unscubscribe anyhow, Exa ain't bending on programming for the TDA1541 or R2R's. Just a S-D device , if thats what you need great.

[exa065]

Originally Posted by regal

This much different than some proporetary unit that claims its digital isolators are better than a 4192to pulse to dig receiver .

Yes, we make this claim. Our users agree with us, some of those who never tried exaU2I bring un-quantified, non-factual criticism. We say that in our experience 108ps of getter (calculated, not measured) on the I2S interface causes artefacts below 140 dB on the analogue output of ES9018. Basically it is beyond what we can measure. Nobody has demonstrated the opposite. Subjective tests give us thumbs up. Correlation between measurement and subjective tests is the best reward for the designer. Do you know what is the jitter level on the interface that you are using?

Originally Posted by regal

The Exa is a specialized multichannel/active speaker soundcard, great for that application. But the owner is misleading newbies into thinking it is a super low jitter i2s soundcard/computer transport for the buffalo or other stereo DAC implementations is a streatch.

The exaU2I is equally successful in two channel and multichannel mode. For people interested in Stereo the drivers can route two channel to 8 outputs to allow for running DACs in a parallel configuration. The notion that somehow having 8 channel is degrading Stereo playback is again a stereo-type of the past. Looking at our client base - these people are hardly newbies . They've been around since the early days of the analogue sound, they are independent and experienced and they trust only their ears. They are still searching for the illusive sound and they are prepared to take risks and to innovate.

Originally Posted by regal

the cat fell right out of the bag when the PLL PID had to be lossened up to get it to lock.

Now you are trying to mislead the audience. It has been established already that lock is lost because I2S involves frequencies that are 4 times higher than I2S, not because of Jitter. Are you seriously claiming that there is an SPDIF implementation that has less jitter than exaU2I?

Are you saying that all other I2S devices discussed earlier here on this thread are inferior to SPDIF in terms of jitter because they also experience lock issues when used with DAC settings optimised for SPDIF?

Are you suggesting to newbies that it is better to use ES9018 DACs with SPDIF sources?

[exa065]

Hi guys,
Let me get back to the Stereo vs Multichannel discussion. Personally, I listen to music sources in their original format - I don't derive rear channels from stereo recordings and I don't downmix multichannel sources. I try to minimize processing throughout the signal chain - analogue and digital - and to listen to recordings as they are made. To me multichannel should be given as much attention as stereo. There are enough audiophile grade multichannel recordings to justify the experiment. Ideally I want to be able to listen to any sampling rate / any lossless format / any number of channels the way they sounded in the recording studio. As a DIY person I want to do this on my terms. This is the only way to be in control, to eliminate unnecessary clutter, to get indulged in the exciting stuff.

To achieve audiophile grade multichannel is more difficult than doubling the speakers and the amplifiers. However the payback is really exciting.

Now that the Pink Floyd Immersion bluray disks are out, what would you do to listen to the Alan Parsons 96 kHz Quad mix of the Dark Side of the Moon? Have you listened to the Brothers in Arms 20th Anniversary edition in 5.1DSD? Both recordings utilize all channels at full rage. To get the complete experience you need at least four fully potent speakers and amplifiers. To me a fancy receiver and a subwoofer won't be able to get you there.

Should we reject multichannel because it is mostly occupied by movie sound tracks and gaming effects?

Personally I hunt for high-end multichannel recordings and I enjoy the "within-the-orchestra" experience.

exa065