Tír Na HiFi

jkeny wrote:Thanks for the pics, Pearse - very interesting
This device is regenerating the USB signal so it effectively does the same a the Regen but I see some potential weaknesses in that part of it's functionality

I can see that the device uses Xilinix FPGA to do the heavy lifting although the two chips (are they from FTDI?) between the FPGA & USB ports I would guess are responsible for translation to/from USB signal protocol. I see the isolators between the two sides of the board (giving 8 channels in each direction) & also the coilcraft transformer spanning the two sides of the board which I presume is responsible for the isolation of ground & +5V but I can't see how this can really provide clean PS on the other side - it is 5V on primary & 3.3V on secondary side - also the spec for the Intona says "Powered by USB host device; internal DC/DC converter for isolated side" - this whole PS area, I expect is a possible weak link although it appears to be helping SQ by isolating the other pathway for noise transference, the USB D+ & D- data lines

If the "clean" side was powered by a good PS supply, I reckon there would be some improvements. What I also don't see is a clock on the board but there is one black block that might be it ( I can't read the ID) - a decent clock with good PS might also be an improvement, I reckon.

But all very interesting - thanks for posting, Pearse

nige2000 wrote:is that two usb2412 chips on each end?
doubt theres any need for 5v on this
maybe new 3.3v supply?

randytsuch wrote: So for power, I'm guessing they are converting USB +5VDC to an AC voltage, passing the AC through the coilcraft transformer, and then rectifying the AC, and regulating it on the isolated side. You can't pass DC through a transformer, so I don't know another way to use USB 5V to power the isolated side.

I see three little linears on each side, probably to create 3.3V, and some lower voltages. Likely uses the lower voltage to power the FPGA, and another for the USB hub.

If you were brave enough, you could remove the coilcraft and supply 3.3V from a lifepo4, and also figure out if the other two regs will work from 3.3V, or if they need 5V (depends on their dropout voltage).
I would bet it would sound much better that way, versus how it is now, and maybe then you wouldn't need the regen.

Pierce,
Can you read the PN from the little square part between the FPGA (Xilinx part) and the connector?
The little square guy is the USB hub.

Randy

Sligolad wrote:Hi John,

I have the Intona before the Regen so just for the Isolation but as you say if it could do a good job of regenerating USB then maybe no need for Regen.

Below is probably the chip you are referring to and the other 2 pictures maybe help you are looking for clock, i could not see anything!!!

sbgk wrote:slightly off topic, question for JK

http://www.diyinhk.com/shop/audio-kits/ ... witch.html

Has received good review on head-fi, very detailed and analogue like.

Do you think the 48MHz oscillator is the key factor here ?

quote from specs -

"Newest XMOS chip and uses 48MHz oscillator to asynchronous reclock usb audio data to SPDIF line, old XMOS uses only 13Mhz oscillator, over 4x better jitter rejection theoretically."

jkeny wrote:

sbgk wrote:slightly off topic, question for JK

http://www.diyinhk.com/shop/audio-kits/ ... witch.html

Has received good review on head-fi, very detailed and analogue like.

Do you think the 48MHz oscillator is the key factor here ?

quote from specs -

"Newest XMOS chip and uses 48MHz oscillator to asynchronous reclock usb audio data to SPDIF line, old XMOS uses only 13Mhz oscillator, over 4x better jitter rejection theoretically."

Difficult question - really don't know - could also be the internal workings of the new XMOS chip itself; could be the lower inductance of the BGA connector format; could be the driver; could be the external PS option - really impossible to tell.