exaU2I - Multi-Channel Asynchronous USB to I2S Interface

[RayCtech]

Originally Posted by exa065

Supra was unable to make any progress with his Buffalo II. Removing the MCU in his case produced only silence.

Then is might simply be that the SPDIF switch are in the wrong position...

Or that it is a dual mono setup with two Buffalo´s.
If you take out the MCU / Firmware on a Buffalo setup for mono mode there WILL be silence due to the outputs then will be in phase - the MCU / firmware runs half of the outputs in anti-phase in mono mode due to the way the inputs are connected

If there are silence with the MCU / firmware out on a Buffalo then it must be some kind of error in the connections...
Wrong lineup of I2S signals, GND connected wrong etc..

I observed Bunpei posted while I was writing.....

[supra]

Thanks it everyone for their suggestions-I connected it up again and this time it works perfectly, no dropout loops at higher 96k playback.
Thanks again to everyone for advice and especially to exa065 for his back up and help to get the exaU2I working with the buff 2. Have to say I'm really pissed off with the Twisted Pear Audio administrators - they see these sites and their only input is to claim there's not a problem, when they know this has been a problem for many users for some time.
Even a private message was ignored.
Ok I got that off my chest, the good news is that this sounds pretty darn good, I have a pretty accurate system that is also very transparent and I tell you what folks, this is what the master tapes really sound like.
Theres no coloration or augmentation , this is what it is.
What are the implications of using the Buff2 without the MUC chip in I2S mode?
Obviously spdif is out, but is there a function for the MUC in I2S?
Any other audio company would get replacements to customers but I won't hold my breath here.
Thanks again, very relieved to get some tunes.

[exa065]

All credit for solving this case goes to Bunpei and RayCtech. I just facilitated the discussion. Thank you again for your help.

My concern is that I am recommending Buffalo DACs for use with exaU2I. Unless there is an official response from Twisted Pear or we come up with a patch, I will have to modify my message.

[BrianDonegan]

Originally Posted by supra

Even a private message was ignored.

Hey, I just got your PM this morning and replied. I also just saw this.

Russ just posted about it here as well: DPLL Bandwidth setting on B II - Buffalo DAC - Twisted Pear Audio Support

So, the uC on the Buffalo is set to use the optimal DPLL setting, which in our testing with both the XMOS eval and our XMOS solution in development, has provided the best and lowest jitter performance. We have not used this USB interface, so I hesitate to offer an explanation.

We have had no issues with high-res material and the current firmware on the Buffalo, or we would have changed it. I would stress that most people using the Buffalo for high-res are not having any issues.

If you are having success w/o the firmware chip in place, then the default DPLL settings are what you want, as it can deal with higher jitter from the source (lower jitter rejection). Running w/o the firmware, however, means you have incorrect DAC mapping for the I2S signals, so that is not good either.

We will make a "High Bandwadth" version of the firmware available to those who want it with the less optimal default DPLL. That's totally not a problem. I will add a link to the web site for people to order it (will post an URL when I have it set up).

[glt]

Originally Posted by supra

...
Obviously spdif is out, ...

SPDiF should be on with the default condition. Make sure the comparator switch in the BII board is in the right position

Originally Posted by supra

...Any other audio company would get replacements to customers but I won't hold my breath here.....

The real issues is that the ESS 9018 DAC has a 7-step tweakable DPLL setting below the lowest setting available in the older 9008 DAC, and that setting applies to both I2S and SPDIF with SPDIF possibly having a larger BW on the same setting as Mr Bunpei said. I have no doubt that the shipping firmware for the DAC has been tweaked for best performace rather than best customer satisfaction because this is DIY

If you are going "all out" with the exa device, then the best solution is to tweak the setting that can match your configuration with separate settings for SPDIF and I2S.

[NicMac]

Originally Posted by glt

If you are going "all out" with the exa device, then the best solution is to tweak the setting that can match your configuration with separate settings for SPDIF and I2S.

The "best" solution would logically be to improve the jitter performance of the exa device....
Maybe this is the way RayCtech power supply modifications improves the audio quality of the device.
I seem to recall that glt was able to get a better lock with a stringent DPLL setting on Buffalo after upgrading the PSU on a USB/I2S transport.
Just a guess - would be interesting to investigate.
Cheers,
Nic

P.S. Any news regarding OSX drivers :-)

[AR2]

Originally Posted by qusp

hang on AR2, which rme have you got? depending which, you can use totalmix to route an output back to the input without wires and access the audio that way without needing jack at all. just control click the channel strip of the output (see below) that has the data you want playing so that it turns red, then in logic you set the outputs of your crossover to the channels after that. you lose 2 channels, but you dont need to use another application. then as you are probably doing, you hit record and pause to process any audio playing through the plugins and assign your channels. make sense? the output from the bounce will be seen at the corresponding inputs, so to monitor a bounce from channels 1 and 2 as here, from memory they will be available on input channels 1 and 2. if thats wrong just play till you get them, or send me a pm and i'll double check, its been a while since i have used it in this way.

Quisp, thank you for the treasure of info you posted here. really cool stuff.
Many questions, but here are some answers. Until just recently I was using Fireface 800, but I gave it to my son. Now I use Fireface 400. Your advice on rerouting RME is really cool, but my intention is not to use RME interface but instead USB - I2S converter. I am not sure I could use both at the same time? If that is not the case than you solution is certainly way to go. Wave - I have a full collection, quite honestly there are way to many plug ins there, haha I get lost there finding what I need. I wanted to use native Logic plug ins to simplify life, but certainly I will try wave as well. I might have a few questions, but I will send it to you directly, in order not to pollute this thread, you are correct on that one.

I just collected all the parts for my future set up. Now I am up to machining and doing case work to house all. Power supplies are elaborate and will be housed separately. Still trying to conceptualize to whole set up... Will keep you updated.

Thank you very much for such a comprehensive and valuable info. I hope there are other people who would try similar set ups.

[supra]

Originally Posted by NicMac

The "best" solution would logically be to improve the jitter performance of the exa device....
Maybe this is the way RayCtech power supply modifications improves the audio quality of the device.
I seem to recall that glt was able to get a better lock with a stringent DPLL setting on Buffalo after upgrading the PSU on a USB/I2S transport.
Just a guess - would be interesting to investigate.
Cheers,
Nic

P.S. Any news regarding OSX drivers :-)

The M2hightec Evo and Teradak usb-spdif devices with I2S outputs also have problem locking onto buff, so I don't think it is any problem with exadevices, anyway I'm grateful that TPA have come to the party and will provide appropriate firmware.

[exa065]

Originally Posted by NicMac

The "best" solution would logically be to improve the jitter performance of the exa device....
Maybe this is the way RayCtech power supply modifications improves the audio quality of the device.
I seem to recall that glt was able to get a better lock with a stringent DPLL setting on Buffalo after upgrading the PSU on a USB/I2S transport.
Just a guess - would be interesting to investigate.
Cheers,
Nic

P.S. Any news regarding OSX drivers :-)

Hi Nic,
Supra has experienced the same issues with 3 different I2S boards. Bunpei has reported the same behavior with his SD Card Player. It appears many I2S devices on the market require flexibility with the Buffalo DAC settings. We all welcome the support from TPA on this issue.

As I have mentioned before, the jitter levels of the exaU2I board are well within the jitter cancellation capability of the ES9018 chip. Evidence of this is the customer satisfaction level and the measurements taken on the analogue output of exaU2I-ES9019 couple. It is easy to pick on any device by taking one specification out of the context of the overall result. There is integrity to the exaU2I that is more important tan one specific measurement. For sure the device is not perfect, however it is the first and only solution on the market that can offer 32/384 quad for less than $12000.

Mac drivers are under development. We actually enjoy the Mac development environment. However I will miss the Foobar sophistication and freedom when I move on the Mac side

-exa065

[exa065]

Originally Posted by BrianDonegan

We will make a "High Bandwadth" version of the firmware available to those who want it with the less optimal default DPLL. That's totally not a problem. I will add a link to the web site for people to order it (will post an URL when I have it set up).

Hi Brian,
Thank you for offering a solution for using third-party I2S devices. A Buffalo DAC-exaU2I combo offers performance that is hard to match with consumer or professional gear.

-exa065