Benchmark AHB2 Experiments
I’ve been using one AHB2 amplifier for a couple of years. I recently acquired a 2nd AHB2, thinking that the sound quality might be better if I used only one channel of each amp, with both amps set for Stereo.
In this configuration, the ease and resolution improved. Sibilants, the "s" sounds, became more natural and connected to the singer instead of sounding like a separate sound. The natural ring of cymbals also increased, sounding less like hiss and more like metal. Soundstage depth increased, too.
Take aways: If using one AHB2, adding a 2nd amp with both amps in Stereo mode and using only one channel of each amp provides a noticeable improvement.
If using two amps in Mono, and if you don’t need the added power you get with the amps in Mono, try the above configuration.
Happy listening!
I was thinking about doing exactly this, glad I found this discussion. After musing over what to do with my setup, I finally concluded that my setup is good enough and a great way to upgrade my system for relatively little coin was to add another AHB2. My setup is a little different as I am using an 8" single driver sealed box speaker, so the bridged watts are not a need; 100 is enough, so I will keep the duo in stereo mode. |
Driving 8 Ohms in bridged mono is equivalent to the load produced by driving 4-Ohms in stereo. Most amplifiers produce more distortion when driving a 4-Ohm load instead of an 8-Ohm load. This is not the case with the AHB2. The 8-Ohm and 4-Ohm THD+N is exactly the same and it will be below 0 dB SPL at all output levels up to full power. This can be seen from the following plot:
Blue = 8 Ohms, Orange = 4-Ohms and Green = 8-Ohms Mono Notice that the vertical axis is plotted in dB SPL at the listening position (assuming a 90 dB at 2.83V speaker efficiency in a typical listening room). You can read more about this here: How Loud is the Distortion from Your Power Amplifier? - Benchmark Media Systems
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"The natural ring of cymbals also increased, sounding less like hiss and more like metal." This is exactly what I am hearing too, and it caused a moment of pause for me when I first listened to this setup. It is real, I swear! There are other improvements, but this was the most obvious one. It sounded like the drummer was in my room. I know this is not something readily explained by the AHB2’s solid design and science, as shown in the above graphs. Thank you, Mr. Benchmark :) Maybe the fact that I now have two power supplies vs. one is a factor? Another thing I did not mention, and maybe this is part of the equation, is that I am using Spotify. So like everything else YMMV.
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