[Mag53]

SPDIF IN/OUT and Fixed and Variable Output

 

[KmanChu]

   
Hi,
 
iDSD micro specification redux...
 
Folks, we totally forgot to mention one more kool feature (way too much stuff happening

).
 
The iDSD micro will have a switch allowing to be selected as either direct DAC line out (2V, Fixed Level) or as variable Preamp out with X-Bass available and up to around 4V RMS output. So if you want to use your own preamp, have it your way. If you want to just drive active speakers and not fork out for a preamp, have it your way.
 
The switch is below the RCA Sockets, so not in the pictures we posted of the mechanical design, hence it was forgotten.

 
So you won't be able to switch the xbass and 3D in and out when using the DAC in line level mode? I suppose it makes sense to bypass as may switches as possible. But, I would say please, please, please make the 3D and xbass so they can be switched in and out of the lineout circuit path independently. I currently have a micro iCAN and love it but was thinking of going to a non-iFi all tube amp. I would love to be able to use the 3D and Xbass independently but bypass the volume pot. Would that not be possible? I understand I was one of the ones begging you to just make the best sounding pure DAC you could so I can't complain. But ... it would be awesome if the preamp stage, 3D, and XBass could be switched in and out indepently.
 
Still, I am stoked and looking forward to the final design.
 
BTW, the nano iDSD is getting some love over on computer audiophile. One prominent poster over there is saying his iUSB Power + Gemini + nano iDSD outperforms his Mytek dac with DSD material. Pretty amazing.

 

[ClieOS]

Originally Posted by iFi audio /img/forum/go_quote.gif
...
 
The iDSD micro will have a switch allowing to be selected as either direct DAC line out (2V, Fixed Level) or as variable Preamp out with X-Bass available and up to around 4V RMS output. So if you want to use your own preamp, have it your way. If you want to just drive active speakers and not fork out for a preamp, have it your way.
 
The switch is below the RCA Sockets, so not in the pictures we posted of the mechanical design, hence it was forgotten.

 
Excellent. Indeed a very cool and practical feature to have.

 

[tf1216]

Can you folks please share what receiver chip is being used for the USB input?  

 

[bjas406]

   
Hi,
 
iDSD micro specification redux...
 
Folks, we totally forgot to mention one more kool feature (way too much stuff happening

).
 
The iDSD micro will have a switch allowing to be selected as either direct DAC line out (2V, Fixed Level) or as variable Preamp out with X-Bass available and up to around 4V RMS output. So if you want to use your own preamp, have it your way. If you want to just drive active speakers and not fork out for a preamp, have it your way.
 
The switch is below the RCA Sockets, so not in the pictures we posted of the mechanical design, hence it was forgotten.

Bingo! So, with the micro iDSD I'm getting a quality USB input that accepts all resolutions, a quality digital to analog conversion and a quality simple line-out to my preamp. Also, I'm getting a number of other features (with the same quality, I assume) that I don't personally need, but that I'm not paying an exorbitant amount for. My last hope is that the micro iDSD will ship with ASIO 2.2 compliant drivers that will permit the iDSD to receive DSD bitstream without the DoP protocol. Fingers crossed.

 

[ClieOS]

  Can you folks please share what receiver chip is being used for the USB input?  

 
If it is anything like the nano iDSD, it probably is a XMOS running on custom firmware.

 

[kugino]

If it is anything like the nano iDSD, it probably is a XMOS running on custom firmware.

I thought I read on the nano thread that they're not using XMOS for the nano...maybe I misread something, but I think it might be something built in-house.

 

[ClieOS]

I thought I read on the nano thread that they're not using XMOS for the nano...maybe I misread something, but I think it might be something built in-house.

 
It is XMOS, but it is also a custom implementation in order to achieve some features that you won't typically find on the vanilla flavor XMOS.
 
Here:
 

  Which USB Asynch does iFi use? AMR's of course!
 
We have been asked more than once or twice "Like most Audiophiles, I like to know where the Asynch code is coming from. It's silly not to touch on that in the documentation...".
 
We thought it was quite clear.....it is our own code of course!
 
Using someone else's off the shelf solution is great if you want a turnkey solution that you pay a small licence fee per unit shipped and can live with certain limitations such as only being able to use one vendor's DAC chips. Along with the XMOS and ESS reference designs, you just plug them together and you have an all singing and dancing USB DAC.
 

 
During the development of the DP-777 we evaluated many USB Solutions (including ones then still in Beta).  We found that no "off the shelf" solution that quite suited our needs and requirements.
 
It should be noted that the fundamentals for Asynchonous USB Audio are part of the USB Specification (under USB Audio Class), so in principle anyone with enough time and a fast enough CPU/MCU/PIC/FPGA can write their own Asynchronous USB Firmware for such a device, according to USB Audio Class documentation. The first commercially available solution for this was Gordon Rankin's "Streamlength" which has become very popular indeed. However since then, many solutions have become available, including the open source USB Widget.
 
We do have our own software team (in addition to the electronic and industrial/mechanical design teams) so we decided to build our own on the XMOS foundation. As a result we were able to greatly customise the XMOS Firmware in the iDSD nano. The fact that the AMR DP-777 and iFi iDAC worked with iPhone/iPAD + Camera Kit when no-one elses USB products did is also owing to us writing our own software (and being Apple "Made For iPhone" Licencee). 
 
Writing our own code allowed us to use the DAC Chip we wanted to use, with DSD and DSD128 and with 352.8/384KHz PCM which is not possible using any of the off the shelf solutions in circulation (they all tend to work only with ESS DAC Chips) but need an extra external DSP Chip or FPGA. Doing this seems a waste if you already have paid for a RISC CPU that manages 500 Million Instructions Per Second [MIPS] (for reference, this is the same as a late 1990's PowerPC Chip or Pentium Pro at 200MHz), plus if you can program that FPGA or DSP Chip - you might as well program the XMOS CPU.
 
So that is what we do. Who's Async Code do we use? AMR's of course, nothing else does what we need.

 

[kugino]

It is XMOS, but it is also a custom implementation in order to achieve some features that you won't typically find on the vanilla flavor XMOS.

Here:

Aah yes. That was the post. Thanks for finding it and verifying.

 

[iFi audio]

All the Names in the Hat?
 
Hi all,
 
The poll has finished and thanks very much to all of you for entering.
 
For sure, desktop 75% / portable 25% came top with 36% of votes. As 50:50 was 2nd and this is a broad grouping, then it is reasonable to assume that some 50% of you use desktop over 50% of the time and portable just under 50%.
 

It was really good to know how each of you enjoy your tunes.
 
We still have not received names/monikers of all those who voted.
 
Those who have not posted that they have voted in the poll, hurry up and let us know!
 
You have another 48 hours to catch this message (as we appreciate you are not always here on HF).
 
So this weekend, we shall put all the names in a hat and 5 of you gets an iPurifier on the house!

 

[pekingduck]

I voted: Desktop 25% Portable 75%

 

[BillsonChang007]

Whose hat is it? xD

Good luck guys!

 

[semeniub]

I voted 75% Desktop, 25% Portable.

 

[calluna]

I voted 75% Desktop, 25% Portable too.

 

[tf1216]

 
 

   
It is XMOS, but it is also a custom implementation in order to achieve some features that you won't typically find on the vanilla flavor XMOS.
 
Here:
 
Originally Posted by kugino /img/forum/go_quote.gif


Aah yes. That was the post. Thanks for finding it and verifying.

 
Thank you.