It is still worth, it makes chassis of two devices electrically same chassis. It doesn’t matter if that combo has chassis grounded (earthed) or not. Ground is just yet another electrical potential, it could be also virtual potential placed at -1000V DC if you like (it would be just dangerous) and everything could be referenced to that virtual ground.
It is ground if it is a desktop. If it is a laptop running on battery it is not. If the laptop is running from PSU, it is about 50/50 chance if it’s grounded or not, my Fujitsu is floating also in that case and same goes with the Acer too. But ASUS has chassis grounded in such case.
Yes, and I also have such RCA single ended adapters that came with my measurement kit, that connect RCA to pins 2+3. Which is a floating ground alternative for the BNC inputs. Single-ended RCA doesn’t need to be grounded either.
But you don’t want both USB and the RCA/XLR shields connect to the chassis and have current flowing from the computer to the amplifiers through the DAC chassis and cable shields. This is the main problem you want to avoid.
That is precisely what you don’t want, because it creates the problem I’ve shown.
If your amp in first place has all audio connections through XLR, which is usually not the case. And then it depends whether all those other connections are so called safety isolated, IOW floating ground (two pin power) or earthed (three pin power). And which of the two types the amplifier is. I have both types of amplifiers. For example my Harman/Kardon HK990 has two pin IEC power connector, which is also the case with my Yamaha AVR (which is not in use at the moment). While the others have 3-pin IEC power connectors, the biggest one having the rather unusual 16A 230V IEC power connector (square with three horizontal flat pins).
If the common ground just passing through from eg the USB card, to the DAC with drain wire to the chassis and on to the balanced drainwire to protective ground in the power amp. Noise passing in the chassis cannot cause the level noise problem as an USB shield landed in the sheet metal shield of the USB port, soldered on the digital card itself, which in turn make the pcb ground plane wobble loosing its steady ref voltage. Noise passing in the backplane, will not cause the stray. Further you get the cabinet grounded two ways which ever have the lowest possible ground potential; the pc chassis (yes desktop with steel cabinet) or the power amp. Both ways leading at my place to same mains distribution block and equal potential od the star ground rebuild I did. This way, the noise will not reach any of the cards, neither digital nor ananlogue, as far as I can see it. You are welcome to explain.
My amp is a Benchmark power amp ABH2. It is grounded, would not have it any other way. Had the H/K you mentioned. It is illegal, but I rebuilt it to three pin protective earth, re-wired the power inside which was a interference nightmare. Added zobelnet and decoupling before and after transformers.
I blocket the pin 1 from entering the pcb, as well as disconnected the ethernet cable for the HRS-link, and drained it to chassis. Finally the darn amp shut-up. Did the same with the CD, connected it with HRS-link and got a jitter washer through the CD which at the time was quite OK. The amp was not silent no matter what I tried, until I gave up and put the chassis to ground level. We do have different postures how to look at ground issues. Darn you are so long away, I would really like to meet one day and I would really like to have your ways as described above showed and measured IRL.
For the time being I will do nothing when I reveive the stuff. But the I will experiment, by soldering a short lead from both USB connectors outer shield. Then I will place a pack tape oven the remaining surface, isolating the shield from the port and instead screw the short leads to the PC chassis and to the DAC chassis. Before I screw the leads, I will take my oscilloscope to see what potential the leads have to their respective chassis and check them one at the time. Before I even start, it would be interesting to measure the potential at the DAC USB port shield, to see if there is noise, it might be sufficient just to connect the drain wire in the PC side…
For me it works great, dead silent without modifications, also through unbalanced connections, because I take care to use it as designed and not hooking it it computer PE.
It’s a nice amp, power amp section seems to be from Mark Levinson. If you look at the schematics, you notice even the schematic drawing style is different for the power amp section compared to he other boards.
I have audio systems in three rooms and servers in two of these and network endpoints in all three. Powers of different rooms come from different phases of the 3 phase mains entering the house.
Today it har been a long long session to determine if the computer USB output can be cleaned up by an additional card, in my case the Matrix Audio Element H, and it has been worthwhile the waiting. Since this card allows for connecting the linear psu only, the others I have been reading about need also the inside PC psu SATA power connection. And off course, it is a remarkable difference, the noise is lowered like an entire layer’s gone.The clarity of the highs with the noise gone, subsequently reduces resonances, hence dc-shift is also lowered. I ahev reached the level I can live with, but that won’t happen as perhaps all here think from time to time
Now, there is the question with organizing the ground between the three very delicate subsystems, USB card, DAC, Linear PSU and Power Amp (oppps, four). I will update as soon as there are some modifications done and the result. I have listened carefully to Jussi’s input, and will work myself from his suggestion and out, to see what finally will remove the tiny, tiny sibilance still left on a few tracks I can live without. But the curiosity killed the cat, so I will not give up. If you wanna check one of the tracks yourselves, find Pat Benatar - Fire and Ice (Remastered) at Tidal. Either the mix or the master is completely of the grid, or it strikes something in my rig that still resonates even after a having replaced almost all equipment. The darn track is too good though to not play, so I satisfiy with the old CD rip.
So, I guess the final touch is to further help each device in keeping the signal ground as clean as I possible can working from the outside. It will be both the balanced cables and the USB cable shield drainage that will be scrutinized.
And just letting you know, the computer I built, with a Matrix Audio Element H USB PCIE Card, recognized by the HQPe software, powered by a Keces P3 linear PSU and not connected at all to internal PC PSU, feeding the USB input on the RME ADI-2 DAC fs, is among the most musical experience I have ever had outside live music. The HQe upsamples to DSD256 over PCM, and filters using poly-sinc-xtr-short-mp. I can sit a whole day with a big, silly grin on my face - just playing track after track after track … life is good
Ain’t it just typical. Building THE HQP computer to a friend and the motherboard, after lots of trials declared dead on arrival. It took a while to determine … But I will put the pics for you tomorrow, when the rig is mine again. Now it is just Olympics running … - booooring - … But as a Swede, I am a bit proud of the outcome. Funny that the dead shure medals is the only one’s not delivered …
Hi, have not published anything, because as Jussi said, there is nothing different compared to an existing high speed USB controller on mother board. Nothing differs and only thing shown is the RME DAC. Sorry, not more exiting than that … Except SQ… so good I have not got used to it yet. Usually it is, ok better, one hour later … whats next? Now, f*ck, let the tech geek rest, play music, enjoy, forget about tech stuff at least this week …
