Benchmark AHB2 Amplifier with THX AAA Technology Arrives for Review

The included remote control for the DAC2 HGC is made of high quality aluminum.  There’s nothing at all cheap or flimsy about it.  The heavy duty Energizer industrial grade batteries and spare fuses were another nice touch—no shortcuts.

As with the DAC2, opening the AHB2 box showed that the AHB2 was very well packaged and would easily survive significant mishandling.  The THX Logo once again greets you when you unpack the amplifier.

The AHB2 contains an extensive instruction manual as well as a nicely done marketing brochure to introduce the user to the AAA technology in the Benchmark AHB2.

Inspecting both units up close, I noticed some blemishes and an occasional light scratch here and there.  I also noticed that the bottom of the units were specially labeled as DEMO and PROMO.

I asked the folks at Benchmark about this.  I was told that the chassis of the units were B-stock but that the internal build parts were A-stock.  They were running low on stock and wanted to get review samples into my hands.  I appreciated this effort!   Having units with a B-stock chassis explained why the cosmetics weren’t 100% perfect.  If you happen see such imperfections in any of the following photos you’ll then know why.

Looking at the AHB2 amplifier, you just can’t help but scratch your head as to how small this thing is.     It’s tiny.  Yes, I’ve seen and used  tiny Class D amplifiers.  This isn’t the same thing.  This is unlike any amplifier you’ve ever seen and you’re left asking yourself, “Will this thing really drive $500, $2,000, $10,000, or $20,000+ speakers?” It’s like someone took a huge Class A amplifier and shrunk it by 50%-70%.  That’s perhaps the only way I can describe it.  It only took up about 1/3 of my shelf!

Small as it is, it feels like a premium, audiophile amplifier.  Its all-metal construction gives it serious heft and weight.  There isn’t anything—anything at all—flimsy about it.

As you unpack the accessories and look at the amplifier in detail, you’ll immediately notice that this unit has been specifically designed to handle the rigors of professional use.  A telltale sign of pro gear is locking connectors.

In the pro world, when you plug something in you want it to stay connected. Accidental pulls are a no-no.  Therefore in pro-gear, your plugs lock.  It’s as simple as that.

The AHB2 shows this pedigree by including a locking power cord.  Insert the AHB2’s included power cord and it will lock in place.  To unplug it, simply depress the red button on either side of the cord to release it from the unit.  Of course, you can use a non-locking cord or any standard IEC power cord.

Except for the standard speaker binding posts, all inputs and outputs on the AHB2 are likewise all locking.  There are no unbalanced/RCA input options.  If you have a preamplifier with unbalanced connections and you want to use the AHB2, then Benchmark sells RCA to XLR adapter cables.

As I mentioned, Benchmark sent me locking speaker cables to use with the AHB2 in addition to my standard speaker cables.  The Benchmark NL2 to banana cables are again high quality (have you noticed the theme here yet?).  The cables are 11 AWG and have a pair of 14 AWG conductors in a star-quad configuration.  I personally use a set of Audioquest speaker cables featuring two pairs of 14 AWG conductors in the same star- quad configuration for years.

I wish more audiophile amplifiers featured the SpeakON connectors.  I love them.  Connections are simple and secure.  There’s no second guessing.  Trust me, once you use the SpeakON connections on the AHB2 you’ll rue the day you have to go back to standard banana cables, spades, or bare cable.

Let me say it perhaps more emphatically: The AHB2’s build quality represents the best that “Made in America” signifies.  The materials, craftsmanship, and design are all top-notch.  Everything with the unit is clearly and logically labeled.

The left side of the AHB2 amplifier also provides you with a toggle switch to use the amplifier in its default stereo or in a bridged monoblock mode.  If you switch the unit into bridged monoblock mode, there’s a dedicated SpeakON connector in the middle of the unit dedicated just to this mode.

The left rear of the unit sports a sensitivity switch.  This switch sets the amplifier gain.  It will help match the amplifier to maximize the signal to nose ratio of your audio system. According to Benchmark, if you set the switch too low, you won’t be able to drive the amplifier to its rated output.  If you set the switch too high, then the noise produced by your preamp will be amplified more than necessary.  The included user manual gives you all the guidance you need to set the switch properly.  

The front of the unit contains more status lights than audiophiles are likely accustomed to—and this is a good thing.  Normally, audiophile power amps are minimalist.  They will have a power status LED and perhaps a channel light.  If there’s a fault, the channel at fault will normally blink.  I’ve always found this approach way too limited and I love what Benchmark did.  You have an LED for power, a separate pair of LEDs for mute, temperature fault, and clipping.  There is a set of LEDs dedicated to each channel.

The AHB2 user manual provides you with a comprehensive matrix of possible fault conditions and how the status lights show you specifically what the fault condition is.  The AHB2 can tell you if you have a problem with clipping, over current, temperature, a power supply fault, etc.

When you power up the AHB2, it goes through a power on sequence as you can see in the image above.  Before the amplifier goes into its operating mode, it will mute both amplifier channels so you don’t experience any pops or other surprises.  Only then will the amplifier go into full operating mode.

As you’ll see in the forthcoming full review, these status lights came in super handy in helping diagnose a problem that arose during the review period with the Revel Ultima2 Salons that I paired with the Benchmark AHB2.  That’s right, we’re going to pair this setup with some of the most critically acclaimed speakers on the market today.

An item I wanted to note the AHB2’s auto-shutdown feature.   By default, the amplifier is set to go into power standby after 45 minutes of non-use.  In other words if there’s no audio signal to the amplifier it will automatically turn off.  This is a great feature to save power but may have some unintended consequences.  For example, when the AHB2 executes an automatic power down, it will also pull the 12V trigger to shut down any equipment chained to it.  You’ll therefore need to plan your audio architecture accordingly.

What’s a bit unusual about the AHB2 power down is that if you then send an audio signal after 45 minutes, the AHB2 won’t auto-power back on.  There’s no auto signal input sensing mode.  You’ll manually need to power the AHB2 back on.

To summarize, let me just say it again: The AHB2 and DAC2 HGC were an absolute joy to unpack and admire.  The units are just beautiful, wonderfully well thought out, and built like tanks.   Integrating these into my existing setup was a breeze and I had loads of flexibility.  I can’t imagine an environment where you’ll be stumped.

These are audio investments that scream quality and are made for years and years of reliable, high performance use.  You can tell that Benchmark has paid attention to detail throughout the industrial and technical design of these units.

Minus the B-stock condition of the chassis, I couldn’t find a single thing to fault or criticize with either unit.  I’m looking forward to taking the AHB2 THX-technology driven amplifier for a serious workout and experience what the Benchmark DAC2 will bring to the table.

Stay tuned for my full review.  If this preview is any indication, this should be one seriously fun ride.