Thank you very much for your prompt responses and the detailed explanations, John! You really helped me piece it all together and visualize it. So i will attempt to verbalize my thoughts as a summary.
My hat is off to you and the Benchmark engineering team for designing these ultra high-quality products, that have given me countless hours of listening joy! Thank you for making yourself available and for the effort you are putting in to answer questions and to educate audiophiles like myself through your posts and release notes on your website, and for being transparent and honest. I can’t think of any other products, at least none that i have come across, where the manuals are so informationally rich, and for a good reason - nothing but solid, top-notch engineering and charts and specs to prove it. Clearly Benchmark products are measurement driven and striving for engineering perfection. Your approach to designing audio equipment- to sound great it must measure great, reminds me of Peter Aczel from the Audio Critic who i highly respect for his no-nonsense, technical approach to evaluating equipment and educating misinformed audiophiles, inundated with purely subjective and deceptive evaluations where somehow average measuring equipment miraculously sounds proportionately good to the price tag. All of these practices only serve to confuse audiophiles and push sales of more and more expensive products leading to absurdities like $10k speaker cables, which don’t measure any better than well designed cables costing a tiny fraction, but somehow possess supernatural properties, bringing the owner sonic nirvana. It takes a lot to excite Peter Aczel about a product, but his glowing review of the Benchmark DAC1 back in 2005, really got my attention and drew me to the company. I am so glad he did. From everything i have learned, analyzing the chart i put together with your help, i see that the LA4/HPA4/AHB2 are so well engineered and far exceed the capabilities of human hearing considering practical listening levels (even at any level if you can bear the loudness), ambient room noise, and sensitivity of most speakers out there, that there is virtually no practical and appreciable sonic improvement possible using the 3 components together, that would bring further sonic benefits. Only on Audio Precision graphs. From what I see, only in the case of using DAC3 without LA4 with sensitive speakers above 93db SPL the system would theoretically start picking up low levels of THD distortion at full power with THD of -113db (good luck to your golden ears). Below -8dbFS THD is -120db. Good luck detecting any distortion at normal listening levels. Noise will be picked up with speakers of 103db SPL or above, for those that have them and can hear it in a normal room at a normal distance. I am so glad i went through this exercise. I would take engineering perfection any day even if i can’t take full advantage of it. Even thinking about the extreme case of those Avantgarde Trios with 109dB sensitivity, as long as an LA4 is inserted in the chain there will be no noise with SNR of 112-115db at 2.83v and no harmonic distortion, which would be at -113db, even if one can bear listening at those levels. Anyone who thinks they can achieve a more perfect sound by “upgrading” from here especially for those of us with speakers where any noise and distortion is buried so deep at 15-30db below the speakers‘ sensitivity are in my humble opinion chasing ghosts. There is zero noise and zero distortion generated by the system. Look at the speakers for any distortion, but it’s not coming from these. The system is basically a straight wire with gain. The only possible situation i can think of where one might hear some differences with other amps is with some extremely difficult speakers, with huge impedance and phase shifts. My speakers have impedance variances from 18ohms to 0.52ohms and phase shifts from -60 to +60 degrees, but the AHB2 drives them effortlessly. They sound fantastic to my years. I am not sure where the limitations of the AHB2 lie in that regard. I would let John fill us in on that. I know some amps can become very unstable with large shifts and not sound good. No offense to anyone, but If they claim they can hear an improvement in sound quality with a different system given the speakers are within the impedance and phase shift capabilities of the AHB2, have other issues. The only people who are excused to hear an improvement are those audio magazines shills who get advertizing revenue from manufacturers and will tell you that Benchmark sounds excellent but that $40k amp sounds even better though it most likely measures worse. My audio electronics quest is over. The only reason I would trade in my Benchmark components for upgraded versions of Benchmark would be for improved visual synergy between the components, but that’s a whole other topic that we can get into if anyone is interested.
John, I wish you and the company continued success! To everyone else, happy listening to your Benchmark systems!
