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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!

imjerrys
hgeifman
2,201 posts
 

Are you really saying that when ‘Using’ two stereo amps in one-channel mode offers better sound quality than running them in mono mode?

Is it true that when a stereo amp is bridged to mono, it doubles the voltage and halves the impedance, which can increase distortion and stress the power supply?

So, based on your post above, running each amp in one-channel mode allows for better separation and less strain on the power supply, potentially improving sound quality. However, I suppose. the actual improvement depends on the specific design and capabilities of the amplifiers used. Thoughts?

imjerrys OP
15 posts
 

I didn't spend much time using the amps in mono mode, so I haven't drawn conclusions about that configuration. Mono sounds a little different than Stereo, but that difference is smaller than when ‘Using’ two stereo amps in one-channel mode.

My speakers have a sensitivity of 88 dB (B&W 805 D4 Signature) and I never see the protection lights on the amp(s) when running in Stereo mode, so more testing in Mono is needed.

yyzsantabarbara
4,829 posts
 

The AHB2 is better in stereo over mono by a tiny bit, though Benchmark says otherwise. That is if your speakers are good with 100 watts. This especially true if your speakers drop to the 2Ohm range. Then the stereo sounds better than mono to my ears.

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