Constellation Altair II Linestage and Hercules II Monoblock Power Amplifiers

A Landmark Refined

Equipment report
Solid-state power amplifiers,
Solid-state preamplifiers
Constellation Altair II,
Constellation Hercules II
Constellation Altair II Linestage and Hercules II Monoblock Power Amplifiers

No other electronics manufacturer in recent memory has risen from start-up to major global brand as quickly or as decisively as Constellation Audio. The company appeared on the scene in late 2010 with the ultra-tweaky (and ultra-expensive) Altair linestage and Hercules monoblock power amplifiers. In my review of those electronics in Issue 215 (September, 2011), I concluded “the Altair and Hercules set new standards in transparency, resolution, absence of grain, and sheer realism, in my experience.”

Constellation leveraged this early success by creating a full line of components based on the same circuits found in the Reference Series Altair and Hercules. (The Performance and Inspiration Series are simply less elaborate implementations of the topologies developed for the cost-no-object Reference.) As we enter 2016, Constellation is armed with the $12,500 Inspiration Integrated amplifier at one end of its line, and the newly revised and updated Altair II linestage and Hercules II monoblocks at the other. The Altair II’s price of $70,000, and the Hercules’ tag of $170,000 per pair position them at the top end of the price scale. Are the revised components better-sounding than the originals? Do they still hold their status as the state of the art in solid-state amplification?

Before tackling those questions, let’s look at the key differences between the new products and the originals. The most obvious change is the Altair’s more traditional user interface. The first Altair was housed in a monolithic chassis with no display or readily apparent controls. Despite the exceptional two-handed touchscreen that controlled the Altair, the lack of controls or of a display on the Altair was a bit unnerving. Customers apparently agreed that that approach was a bit too avant-garde; the new Altair features a touchscreen similar to that of the old remote, but now integrated into the front panel. The new remote, a slim wand beautifully machined from aluminum, is much easier to use. Overall, the move to the front-panel display and a more conventional remote control is welcome.

Inside, the Altair’s volume control is now a monolithic stepped-attenuator under digital control rather than the elaborate light-dependent-resistor circuit of the original. The light-dependent-resistor volume control took a long time to stabilize and sound its best, leading to the decision to implement the new attenuator. Other changes include additional power-supply buffers around the volume control as well as another regulation stage in the supply powering the audio circuit. The result is reportedly wider dynamics and lower noise. The floating “raft” on which the audio circuitry is suspended has had its suspension retuned, with a heavier weight to the raft and optimized mechanical damping. Apart from a few component swaps, the circuit is unchanged.

The Altair’s power supply is still housed in a separate enclosure, and connects to the main chassis via three umbilical cords. Constellation Audio offers a product called a DC Filter that looks identical to the power supply. It fits in line between the power supply and the Altair’s main chassis, and provides additional filtering of the DC supply voltages before they get to the preamplifier. The optional DC filter can be added at any time, and is priced at $9000. In a typical configuration, the Altair linestage sits atop the power supply and DC filter. When viewed this way, the Altair’s extraordinary industrial design and chassis-work are on full display. The three chassis together almost look like sculpture.

The Altair offers eight inputs, four unbalanced on RCA jacks and four balanced on XLR connectors. You can scroll through the inputs from a button on the remote, but that’s tedious if you want to go from Input 2 to Input 1. A better method is to press a small button concealed beneath the Altair’s front-panel display, which brings up the eight inputs on the touchscreen. The touchscreen also shows you the volume setting, selected input, and balance control (which, incidentally, is adjustable in 0.1dB steps). I missed the ability to select any input directly from the remote, which was possible with the original Altair. On the plus side, the new wand remote is easier to hold and use than the two-handed Pyxis remote.

The Hercules II has undergone more extensive revisions. For starters, the original’s vertical form factor has been replaced by a more traditional chassis. The power rating has increased from 1000W to 1100W. Although the output stage and heatsink area of the two amplifiers are identical, the Series 2 features more robust Plitron power transformers that can deliver higher current.

One of my criticisms of the original Hercules was a bass response that was polite rather than visceral. The bottom end lacked the weight, extension, and authority one would expect from a “super-amp.” That shortcoming has been addressed in the Hercules II by tripling the power-supply filter capacitance and adding another regulation stage in the supply for the front-end audio circuitry. Interestingly, according to Constellation, making either one of these changes without the other rendered only a marginal improvement in bass and dynamics. But together the two changes reportedly resulted in significantly wider dynamics and more robust bass.

Hercules has two sets of inputs, one of them marked “Constellation Direct.” This input is designed for connection to a Constellation preamp; it simply bypasses the amplifier’s input buffer for one less gain stage in the signal path. The output binding posts are big and robust, but the slots in the posts for inserting spade lugs are oddly positioned to face toward the outside of the chassis in opposite directions, making it tricky to connect certain speaker cables. The AC input jack is a 20A connector rather than the typical 15A type. (See the sidebar for a recap of the two products’ technical features.)