USB isolation
Thank you Bunpei for the link.
I did look into usb opto before but costing more than 1K! but this product is well priced. Would have grabbed one but unfortunately have no desktop PC at the moment. Is there any USB-USB opto version?
Also, very interesting to hear that this opto isolation has improved the SQ given that the EXA itself has isolation after the FPGA. So it indicates that isolating the FPGA from PC has benefits.
Thank you Bunpei for the link.
I did look into usb opto before but costing more than 1K! but this product is well priced. Would have grabbed one but unfortunately have no desktop PC at the moment. Is there any USB-USB opto version?
Also, very interesting to hear that this opto isolation has improved the SQ given that the EXA itself has isolation after the FPGA. So it indicates that isolating the FPGA from PC has benefits.
You may find something useful regarding USB isolaters on this page;
The Well-Tempered Computer
The Well-Tempered Computer
you misunderstand me, isolating the dac and clock from USB ground is all well and good, I agree with that and do it myself, but isolating the digital FPGA logic areas from USB and then isolating it again after them...is only theoretical improvement, one I cannot think of a theory for. doing it this way (once directly before reclock stage) does not cost $900 either
data is verified as bit-perfect coming out of fifo main board and clock board with the isolation in place between fifo and clock board, with the only jitter at the output being that of the clock and clock buffer, where is the room for the $900 improvement?
it would be a similar situation with EXA, though with EXA the buffer is not as advanced and the isolation is after the reclock stage? used to be anyway, that may not still be the case.
data is verified as bit-perfect coming out of fifo main board and clock board with the isolation in place between fifo and clock board, with the only jitter at the output being that of the clock and clock buffer, where is the room for the $900 improvement?
it would be a similar situation with EXA, though with EXA the buffer is not as advanced and the isolation is after the reclock stage? used to be anyway, that may not still be the case.
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USb Isolator
Bunpei, Price is a factor. Local distributor asking ~$1400 for the Icron USB Ranger!
I will drop the usb isolator in priority for the time being. The Turbo Reclocker should take care the 'limitations' of the EXA2UI and then see if any usb isolator will improve on this.
Bunpei, Price is a factor. Local distributor asking ~$1400 for the Icron USB Ranger!
I will drop the usb isolator in priority for the time being. The Turbo Reclocker should take care the 'limitations' of the EXA2UI and then see if any usb isolator will improve on this.
It's worth noting that Ian recommended that if using the WaveIO with FIFO and the FIFO isolator he still recommended using the WaveIO nve isolator chip to isolate the usb from the FIFO FPGA, then FIFO isolator is only isolating FPGA noise from the reclocking stage.
Acko, it might be worth emailing Ian about.
Here is the link to his recommendations for using FIFO and usb audio source via WaveIO - http://www.diyaudio.com/forums/digi...ultimate-weapon-fight-jitter.html#post3218811
Acko, it might be worth emailing Ian about.
Here is the link to his recommendations for using FIFO and usb audio source via WaveIO - http://www.diyaudio.com/forums/digi...ultimate-weapon-fight-jitter.html#post3218811
Yes, I agree. WaveIO and other transports that has no on-board FIFO would benefit greatly from Ian's FIFO-Clock modules. If there is pre-isolation already it is best to leave it as is. I would also take the isolated outputs from WaveIO to isolate the FPGA of Ian's FIFO from PC ground. Lorien mentions jitter this way but hey, we have Ian's FIFO and reclock to clean things up again
On the other hand the EXA2UI has already got its own FIFO and isolators so there is no need to add further duplication of similar functions (and bulk). So I what I am proposing is just to re-clock the outputs of the EXA2UI using the clean DAC Master Clock (100M). On the AKL boards there are also isolators for the divided Slave clocks (from AKX701) replace the XOs of the EXA. The end result is a compact add-on to the EXA unit that has similar benefits as that of Ian's design.
Also from Ian's own comment, the FIFO buffer action does not exactly eliminate jitter (other than reducing latencies in data transfer). It is the isolation and re-clocking with low jitter XOs that gives benefits and if you look closely these drive the way the entire design has evolved.
On the other hand the EXA2UI has already got its own FIFO and isolators so there is no need to add further duplication of similar functions (and bulk). So I what I am proposing is just to re-clock the outputs of the EXA2UI using the clean DAC Master Clock (100M). On the AKL boards there are also isolators for the divided Slave clocks (from AKX701) replace the XOs of the EXA. The end result is a compact add-on to the EXA unit that has similar benefits as that of Ian's design.
Also from Ian's own comment, the FIFO buffer action does not exactly eliminate jitter (other than reducing latencies in data transfer). It is the isolation and re-clocking with low jitter XOs that gives benefits and if you look closely these drive the way the entire design has evolved.
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Agree totally Acko, I know what I linked is different to the topic. I was mainly referring to it as an example of isolating twice which seemed counter intuitive to me when Ian suggested it. Ian's comments refer to keeping the computer noise out of the FIFO FPGA circuits, which is a similar goal to what is being discussed here.
Can you give price and availability?
Looks like it would mate well with my Amanero.
Randy
I'd be interested in the "normally aspirated / average joe" version to connect a cm6631 usb-i2s card to an es9018 dac; the ones from Diyinhk.
yeah mate, consider how many people bought that board and struggle with its proper integration daily....
many have lashed together protoboards etc with very fast logic chips. I have no doubt you would sell quite a few if you can make it more inline with the cost of the amanero, they dont need rogers substrate.
many have lashed together protoboards etc with very fast logic chips. I have no doubt you would sell quite a few if you can make it more inline with the cost of the amanero, they dont need rogers substrate.
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