![]() Wouldn't running the AHB2 in mono reduce this - I think that could be what I observed.ĭefinitely very interested in analysing that particular section of the music (signal), and then maybe understanding what demand is being placed on the amp/ speakers dynamically. I have to admit some ignorance, but wouldn't those instantaneous peaks actually be instantaneously multiples higher than the power levels either side. So could it simply be a case of not enough headroom (1x AHB2 in stereo) for dynamics in a poor recording which are otherwise uncommon (the dynamics not the poor recording), or perhaps these dynamics normally meet other limits before coming up against the amps design itself? This lines up with my observations when running the amp in mono through the one speaker. And it seems supported by what you were saying John (if my understanding is correct) - that the transients are tightly regulated in the AHB2.Īs was pointed out to me by push-pull means 380W into 8 ohms with 29A in Mono, compared to 100W into 8 ohms and 18A in stereo. I think some of the subsequent comments on the post were kind of going towards this idea. This quote was taken from an Absolute Sound review of the AHB2. Both approaches are valid, so you pays your money and takes your pick according to your needs, desires, and wallet. The price there is increased distortion, but the argument goes that because the music is so loud, and the duration so brief, the extra distortion goes essentially unnoticed. But there are other amplifiers with less tightly regulated power supplies that allow for much greater power output on instantaneous peaks (this is a design feature on the NAD amps). ![]() This is salutary because it keeps the amp within its noise and distortion specifications vis-à-vis its power output. ''That said, there is one aspect of the design that must be emphasized: The power supply is very strictly regulated, the 100 watts of continuous power generating only about 110 watts on instantaneous peaks. Is it possible the amp considers the short sharp transient signals as noise and ignores them? Or is it simply a question of available headroom? Or limits to rate of change rate? I think I understand the inbuilt protections in the AHB2 but they don't seem to explain the behaviour observed. This is puzzling actually because at no point did a single light flicker on the AHB2. Before this threshold is reached, the high-current warning lights will flash, but this is not an indication that current is being limited, it is just a warning that you are near the shut-down threshold." Until this shutdown threshold is reached, there is no limit to the output current delivered by the AHB2. The output current of the AHB2 is only limited by an overload protection system that measures the output current and then shuts the amplifier down is an unsafe load (or short circuit) is causing excessive output current. In contrast, the AHB2 output stage is drawing current from tightly regulated power supply rails and there is no current limiting circuit in series with the output stage. The third issue is that the Accuphase may have output current limitations that are contributing additional distortions. The Accuphase cannot damp the drivers as quickly. A second issue is that the damping factor is much higher in the AHB2. ![]() The effect of this is that Accuphase delivers frequencies near 20 Hz slightly late (due to the low-frequency phase response errors which are a direct result 5 Hz lower limit of the Accuphase amplifier). The Accuphase response is -3 dB at 5 Hz while the AHB2 extends all the way down to 0.1 Hz (-3 dB). There are several important differences between these two amplifiers that can change the way the low frequencies are reproduced.
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