That Benchmark system in TAS is my system, except I sold the DAC3B last week. I will buy it back later in 2021 since I already miss it.
I also did a test with a single AHB2 and turned on mono operation to get more power. I then ran it on 1 CS3.7 speaker. I liked it a lot more since I got more bass and things seemed more energized. So I bought a second AHB2 that should arrive in a few weeks.
@tomthiel The Benchmark preamp, preferably the HPA4 over the LA4 because of the bonus headphone amp. I hated headphones prior to getting the HPA4. The Benchmark preamps also make their DACs sound better because the volume control on the preamp is much better. The preamps are quieter than the DAC3.
I am now thinking of trying out the RAAL SR1a ribbon headphone driven by 1 or 2 AHB2 amps (not the HPA4). RAAL used the AHB2 to develop the SR1a.
BTW - I have at one time owned, DAC1, DAC2 HGC, DAC3 HGC, DAC3B, AHB2, HPA4 and all Benchmark interconnects and now speaker cables. I love this gear.