OK - Regular readers will know that I have found some issues with bass performance with USB sources, including both Melco and microRendu. It does puzzle me why bass performance should be fundamentally different from a source feeding via USB and one by AES/EBU. What is wrong with the USB input exactly? It's the same 1's and 0's being fed to the same amp, very puzzling! Then I read the above from John Swenson re 'leakage loops', and this got me thinking....
OK, I will be 100% honest here, I do not know what a leakage loop is or why it may influence audio performance. The reason I am interested is the 'leakage loops' issue as described does appear to exactly match what I have observed via USB. Plenty of bass, that is more bass than via AES/EBU, but bass with less definition and accuracy. Quite notably, this was noted by a number of people at an OAC demonstration of the Aurender N10, where we listened to one track via USB, then again via AES/EBU. Also, it had been niggling me a bit that I had not particularly noticed this issue with the CAD CAT via USB. OK, I listened to the CAD CAT for only about 45 minutes, but bass issues I had noted with the Melco via USB seamed OK via the CAD CAT. However, the CAD CAT was running with their new electronic grounding box device. Could this be the reason the CAD CAT appeared better via USB, that maybe only this device with it's grounding box and external LPSU was somehow breaking the problematic 'leakage loop'.
This is currently pure speculation on my part, I do not (yet) know enough about 'leakage loops' to know if this makes any sense. What I can say is that the evidence does appear to fit the theory. Coincidence? Maybe, maybe not?
EDIT: and another thought..... I recall Guillaume rated the Melco N1Z a lot higher than I did. However, I did think some aspects of the Melco's mid-range performance was absolutely outstanding, it was just the bass accuracy I had a bit of an issue with. However, maybe when Guillaume tried the N1Z in his system, with decent mains isolation kit, the 'leakage loop' issue was fully mitigated, so Guillaume would never have heard the bass issue I did? (more wild speculation that kind of fits the theory!)
OK, I will be 100% honest here, I do not know what a leakage loop is or why it may influence audio performance. The reason I am interested is the 'leakage loops' issue as described does appear to exactly match what I have observed via USB. Plenty of bass, that is more bass than via AES/EBU, but bass with less definition and accuracy. Quite notably, this was noted by a number of people at an OAC demonstration of the Aurender N10, where we listened to one track via USB, then again via AES/EBU. Also, it had been niggling me a bit that I had not particularly noticed this issue with the CAD CAT via USB. OK, I listened to the CAD CAT for only about 45 minutes, but bass issues I had noted with the Melco via USB seamed OK via the CAD CAT. However, the CAD CAT was running with their new electronic grounding box device. Could this be the reason the CAD CAT appeared better via USB, that maybe only this device with it's grounding box and external LPSU was somehow breaking the problematic 'leakage loop'.
This is currently pure speculation on my part, I do not (yet) know enough about 'leakage loops' to know if this makes any sense. What I can say is that the evidence does appear to fit the theory. Coincidence? Maybe, maybe not?
EDIT: and another thought..... I recall Guillaume rated the Melco N1Z a lot higher than I did. However, I did think some aspects of the Melco's mid-range performance was absolutely outstanding, it was just the bass accuracy I had a bit of an issue with. However, maybe when Guillaume tried the N1Z in his system, with decent mains isolation kit, the 'leakage loop' issue was fully mitigated, so Guillaume would never have heard the bass issue I did? (more wild speculation that kind of fits the theory!)
1000 Pro - KEF Blade - iFi Zen Stream - Mutec REF10 - MC3+USB - Pro-Ject Signature 12
