Running Benchmark AHB2 in bridged mode and 4 Ohm Speaker

The issue here is not the amplifier. It is the speakers. If you want high quality and high fidelity then 4 ohm nominal speakers are definitely best avoided. The very low impedance is bound to create amplifier issues (stress) with almost any amp.

Benchmark have been making ground breaking products for years. They are an embarrassment to most of the old school industry. Out performing incumbent market leaders technically (measurements) by considerable amounts at reasonable cost.

This is healthy and exciting for us as hi-fi customers. Of course reliability is always a concern especially with radical new designs. Time will tell if these new products like the AHB2 and the HPA4 perform as reliably as their DACs.

Of course measurement based design targets measured performance and therefore only address a portion of the market. Flavoured designs like tube amps etc. will always have their important place and many audiophiles will continue to opt for flavour over pure tech specs.

That said. You could consider the AHB2 as a transparent way to drive speakers (if you like the sound of your speakers) and then look to a tube preamplifier to add some sweetness or sizzle to taste.