Do you know of what mdsimon2 posted in the post above yours regarding some AB amps vs D amps? Do you think it's a problem and I should hold off? Difference of 1db there at 15khz+.The Topping PA5 does appear to have a lower self noise than the Buckeye NC252. For desktop listening distance, I believe the PA5 should be sufficient.
The PA5 can output 100 W into 4 ohm (<0.01% THN+N), which equates to 20 Vrms. With sensitivity of 85 dB/2.83V, the loudness unclipped volume at 1 m would be 85 + 20*log10(20/2.83) = 102 dB. Two speakers (and neglecting room gain) will raise it to 105 dB. Using my own personal rule-of-thumb, it will be adequate for 82 dB average listening volume, which IMHO should be plenty loud enough. The wall wart is an annoyance indeed.
If it'll work and be enough to test if the speakers are functioning as intended, then that is enough.To connect your ODAC/O2 combo to the PA5, an adapter cable like this one should work, although probably not optimal, since it shorts the negative side of the balanced input of the PA5 to ground. You'll probably have to make your own cable if you feel absolutely have to "do it right".
This graph then for the Behringer? I don't see a graph here that is freq vs phase like pma's graph. If Amir's not testing it anymore and the Chinese tester isn't either, then perhaps we'll just never know how it performs in this metric...For some reason Amir stopped measuring amplifier frequency response in to complex loads. If you look at his Behringer A800 review you can see the frequency response deviation at higher frequencies.
This is a review and detailed measurements of the Behringer A800 Class D Stereo Amplifier. It is on kind loan from a member. The A800 costs US $299 including free shipping from multiple sites. The member who loaned it me has done a youtube video of it which you can see by clicking on this...www.audiosciencereview.com
@pma recently did some investigation comparing a UCD180 (precursor to Ncore) to a TPA3255 based amplifier which showed the TPA3255 amplifier had load dependent frequency response but the UCD did not.
I’m still not getting how this is a class AB vs class D thing then. It might be an issue with the A07’s power supply, or even with the PC or interface, but the amp itself works perfectly well it seems.www.audiosciencereview.com
The Neumann kh80 has a minimum listening distance is 0.5m and for recommended is at 0.8m which is waaay too far for me right now. The Genelec graph breaks it down into recommended vs not recommended. Perhaps for Amir's graph, the Klippel calculated a recommended distance of 0.6m. It's hard to say what basis Genelec and Neumann consider a speaker to be at 'recommended distance' vs 'minimum distance'. I've seen the Genelec graphic before, but it really squished the nearfield distances so it was hard to see what they're saying.Here is Genelec's speaker distance chart. For their coax based Ones (83x1), the smaller ones are good for distances >0.5 m. I'd expect the LS50 Metas to behave similarly.