New Audio-gd R-7, R-7HE R-8, R-27, R-27HE, R-28 Flagship Resistor Ladder DACs and DAC/amps

[newabc]

One thing that USBridge improved from the original Raspberry Pi 3: Raspberry Pi 3's Ethernet and USB ports shares a same controller and bus(link), and USBridge used a Raspberry Pi compute module 3 and a different based board to solve this issue.

On the other hand, Shanti is a pretty good LPS, based on @FredA's comparison between Shanti and the SimpleBest PSU on USBridge. (Discussion thread of SimpleBest PSU: link)

By the way, the cost of USBridge + Shanti is lower than $500.

 

[FredA]

One thing that USBridge improved from the original Raspberry Pi 3: Raspberry Pi 3's Ethernet and USB ports shares a same controller and bus(link), and USBridge used a Raspberry Pi compute module 3 and a different based board to solve this issue.

On the other hand, Shanti is a pretty good LPS, based on @FredA's comparison between Shanti and the SimpleBest PSU on USBridge. (Discussion thread of SimpleBest PSU: link)

By the way, the cost of USBridge + Shanti is lower than $500.

Exact. A good ebay ultra-low noise psu will also do a fine job.

About the shanti, i proceeded to install a.5.5/2.1 socket on it to use a Ghentaudio cable i had. I can' t say it improved the sound but it changed it for sure. The stock shanti is fine. I am sure i could play with dc cable to optimize things as the sound seems to be more dependent on the cable than on the psu in this case. Quite a surprising find.

As for improving the sound, the usbridge sig sure will help. Even more so when used just as a bridge.

 

[sajunky]

I stop reading about ifi defender after getting this "Tired of doing battle with buzz, hum and hiss?"
True for analog connection, but I never heard it on USB connection. It happens for some that mouse movement create prr.prr.prr, but it never happened to me, so I don't know whether it is a leak to the internal sound codec chip, also a sign that PC is not configured in bit-perfect mode. Ground loops affect sound completely different, but it is digression.

Do you want redirection of ground loops from PC, Rpi or another USB source? Get an inexpensive self powered USB 2.0 hub (but not 3.x), replace SMPS charger plug with a quality LPS and it is done. Because a power cord carries ground loops, better get a good cable as @FredA says, as short as possible. Before all this expensive stuff arrive, you can test it on the standard charger plug - it also helps!

 

[XavierP56]

With all the FIFO reclocking inside R7-HE21 / Mk2, what's the purpose of all these USB Reclocker ? Seem useless with the R7HE. Am I missing something ?

 

[FredA]

With all the FIFO reclocking inside R7-HE21 / Mk2, what's the purpose of all these USB Reclocker ? Seem useless with the R7HE. Am I missing something ?

It's all about noise. The better clocked and the more silent the usb signal is, the less noise the amanero will produce. Even though there is isolation with the fpga, it can't be perfect. The di20he improves on the internal usb for the same reason.

 

[Crow123]

I stop reading about ifi defender after getting this "Tired of doing battle with buzz, hum and hiss?"
True for analog connection, but I never heard it on USB connection. It happens for some that mouse movement create prr.prr.prr, but it never happened to me, so I don't know whether it is a leak to the internal sound codec chip, also a sign that PC is not configured in bit-perfect mode. Ground loops affect sound completely different, but it is digression.

Do you want redirection of ground loops from PC, Rpi or another USB source? Get an inexpensive self powered USB 2.0 hub (but not 3.x), replace SMPS charger plug with a quality LPS and it is done. Because a power cord carries ground loops, better get a good cable as @FredA says, as short as possible. Before all this expensive stuff arrive, you can test it on the standard charger plug - it also helps!

not quite following. Should I get a USB hub instead of a plug for RPI? Any links would be much appreciated based in SA

 

[XavierP56]

Hi Fred,

Ok we have noise (analog noise on USB signal) but once it passes the USB Isolator, the FPGA being a computer receives just values.
So analog noise from USB gets "cancelled" in the process.
I'm still unclear why this noise would harm something. Can you provide more details ?

 

[sajunky]

Hi Fred,

Ok we have noise (analog noise on USB signal) but once it passes the USB Isolator, the FPGA being a computer receives just values.
So analog noise from USB gets "cancelled" in the process.
I'm still unclear why this noise would harm something.

USB signal is passing without errors, as errors on the USB connection are very rare. With asynchronous transfers a source frequency and timing is no problem as USB clock is slaved to the internal clock - as long as there are no receiving errors, but again errors are very rare. 5V is not used, no problem. Problem is with a noise on the ground wire. It creates a current flow inside a DAC through the internal power supply for the Amanero module. It creates EMI spreading inside a DAC. There is also interference between other sections of a power supply, and finally a galvanic isolation which is placed between Amanero and FPGA core logic is not perfect. Any capacitance (even very small) between components of a dirty side and a core logic create leak.

In other words, USB give perfect bit transfers, therefore any USB reclockers do not make any sense, the only concern is a noise entering inside a DAC.

 

[XavierP56]

Ok thanks !

 

[sajunky]

not quite following. Should I get a USB hub instead of a plug for RPI? Any links would be much appreciated based in SA

Well, I am surprised, most are either fast charging, type C, blablabla. But, there are still...

1. Unitek model Y-2179B R139. Inexpensive, four downstream ports, out of stock. External power is provided by a micro USB port (charging only). This is as an example what you want. The same R118, cheaper and also out of stock.

2. Unitek model Y-2132 R540. To many ports and comes with power supply you would like to replace anyway, but there is a stock.

Added:
3. This one is fast charging that is complicating design and serve no purpose, but a price is R119, a micro USB port for the external power supply.

 

[Crow123]

USB signal is passing without errors, as errors on the USB connection are very rare. With asynchronous transfers a source frequency and timing is no problem as USB clock is slaved to the internal clock - as long as there are no receiving errors, but again errors are very rare. 5V is not used, no problem. Problem is with a noise on the ground wire. It creates a current flow inside a DAC through the internal power supply for the Amanero module. It creates EMI spreading inside a DAC. There is also interference between other sections of a power supply, and finally a galvanic isolation which is placed between Amanero and FPGA core logic is not perfect. Any capacitance (even very small) between components of a dirty side and a core logic create leak.

In other words, USB give perfect bit transfers, therefore any USB reclockers do not make any sense, the only concern is a noise entering inside a DAC.

 

[Crow123]

So then question is and really just want to understand. I chose ifi defender as It supposed to block noise not for re-clocking per se. Will the above then block the noise your mention?

 

[sajunky]

So then question is and really just want to understand. I chose ifi defender as It supposed to block noise not for re-clocking per se. Will the above then block the noise your mention?

It only redirect a portion to the ifi power supply port. The same as an USB hub with external power supply, perhaps a bigger portion than an ordinary hub.

 

[FredA]

USB signal is passing without errors, as errors on the USB connection are very rare. With asynchronous transfers a source frequency and timing is no problem as USB clock is slaved to the internal clock - as long as there are no receiving errors, but again errors are very rare. 5V is not used, no problem. Problem is with a noise on the ground wire. It creates a current flow inside a DAC through the internal power supply for the Amanero module. It creates EMI spreading inside a DAC. There is also interference between other sections of a power supply, and finally a galvanic isolation which is placed between Amanero and FPGA core logic is not perfect. Any capacitance (even very small) between components of a dirty side and a core logic create leak.

In other words, USB give perfect bit transfers, therefore any USB reclockers do not make any sense, the only concern is a noise entering inside a DAC.

Not sure, reclocking seems to work for some reason.

 

[Jackula]

USB signal is passing without errors, as errors on the USB connection are very rare. With asynchronous transfers a source frequency and timing is no problem as USB clock is slaved to the internal clock - as long as there are no receiving errors, but again errors are very rare. 5V is not used, no problem. Problem is with a noise on the ground wire. It creates a current flow inside a DAC through the internal power supply for the Amanero module. It creates EMI spreading inside a DAC. There is also interference between other sections of a power supply, and finally a galvanic isolation which is placed between Amanero and FPGA core logic is not perfect. Any capacitance (even very small) between components of a dirty side and a core logic create leak.

In other words, USB give perfect bit transfers, therefore any USB reclockers do not make any sense, the only concern is a noise entering inside a DAC.

USB errors are more common than you think, because there is no error correction in isochronous transfer. So the quality matters and so is the distance.

You can try running on 3m USB cable, and a 1m cable, with the same contruction, the difference will be obvious. Then if you add a reclocker you won't be able to hear the difference between a 3m or 1m one.