Anthem STR Preamplifier and STR Power Amplifier

Accuracy, Authority, Adaptability

Equipment report
Solid-state power amplifiers,
Solid-state preamplifiers
Anthem STR Preamplifier and STR Power Amplifier

For eight years, an Anthem Statement D2v processor has been at the heart of my audio system. Multichannel music is a priority for me and in 2011, when I purchased the D2v, there were not many other suitable products at anywhere near the Anthem’s price of $7499. Even now, the current iteration—the D2v 3D ($9499)—has few competitors, and the original pre/pro has continued to serve me dependably with both surround and two-channel sources. But time marches on. The D2v has nary a USB input and its Asahi Kasei Microdevices (AKM) DAC chip isn’t DSD capable. Although Anthem was in on the ground floor with DSP room-correction equalization to compensate for the inevitable acoustic shortcomings in domestic listening environments, I was aware the company had made substantial advances beyond the incremental updates offered to my version of the Anthem Room Correction (ARC) software. So when given the chance to get to know Anthem’s top-of-the-line STR stereo preamplifier and stereo power amplifier, no arm-twisting was needed—even if multichannel capability wasn’t part of the package.

The single most expensive part of many high-end electronic products is the chassis and the STR components will have you thinking you’ve gotten your money’s worth, the industrial design conveying an aesthetic of solidity and understated elegance. The form factor of the two components, both available in a silver or black finish, is similar. The right side of the front panel, gently convex in shape, has a few controls, while the left is dominated by a TFT (thin-film-transistor) LCD display. The amplifier’s virtual VU meters, one for each channel, are entertaining for a week or two but, probably, you’ll eventually decide to turn them off. The display on the STR preamplifier, however, is a strong selling point. From the onscreen “Preferences” menu, the user chooses between two settings, “All” or “Volume.” The former shows the gain level in the center of the display with other useful information at the four corners—the input selected, the format and sampling rate for digital sources, mono vs. stereo, and whether ARC is activated. With the latter setting, only the volume level is displayed, in three-quarters-of-an-inch-high numbers that are easy to read from across a darkened room or in broad daylight. 

The front panel of the STR preamplifier demonstrates just how far the user interface for a complex consumer electronic device has come in a decade. Multiple layers of onscreen menus to program and operate components are now, of course, standard, and the implementation of such systems is something that Anthem is really good at. My beloved D2v sports 41 buttons on its forward-facing surface; the STR pre-amp has just fiveon/off, mute, and three buttons to navigate the menus, in the event you’ve left the supplied remote control back at the listening position. 

The STR’s connectivity is comprehensive. In back are multiple RCA and XLR inputs, several of which can be configured for “home theater bypass” and two phono inputs. This bypass allows the stereo STR preamp to be used in conjunction with a multichannel amplifier in systems that do double-duty for stereo and multichannel reproduction. When this mode is enabled all digital processing is turned off. 

Anthem, as expected, provides all the digital connections you could want (almost—HDMI is MIA), upsampling to 32-bit/192kHz resolution. These include coaxial, optical, AES/EBU, and asynchronous USB, the last of which handles up to 32-bit/384kHz PCM and DSD 2.8 and 5.6MHz, courtesy of an XMOS XHRA-2HP chip. If your computer is a Windows machine, you must download an XMOS driver from Anthem’s website to use the USB interface; for Mac, it’s simply plug-and-play. 

The back panel actually gives only a modest indication of the STR preamplifier’s robust control capabilities; up to 30 virtual inputs can be programmed. Both preamp and amp will automatically turn off rather quickly, unless you tell them not to. There’s a switch on the back of the amplifier that disables the automatic shutdown, and a menu on the preamp lets the user specify that the device will cease and desist in an hour, two hours, six hours—or never. A bass-management menu allows the user to optimize LF performance with adjustments of the subwoofer crossover frequency, as well as polarity and phase.

No one will mistake the STR power amplifier for a Class D model. Weighing in at 60 pounds (it looks more massive than that), this dual-mono Class AB design is rated to deliver 400 watts per channel into an 8-ohm load, 600Wpc into 4 ohms, and 800Wpc into 2 ohms—it consumes 65 watts when idling and from 150 to 300 watts at typical playback levels. 

Inside are enormous toroidal power supplies, sixteen bipolar output transistors per channel, and a proprietary input circuit that Anthem calls “a complementary active-loaded cascoded feedback arrangement.” There are two internal heat sinks per channel. The amplifier monitors internal temperature, current, and voltage, and an “Advanced Load Monitoring” feature allows a concerned user to check on the status of things as often as that user’s psyche requires. 

The owner’s manual does advise that “bass-heavy music” played loudly could raise the temperature sufficiently to trigger automatic shutdown of the amplifier. In my room in May, the amp’s internal temperature was in the 97° to 100° range after idling overnight, increasing by about 10° with half an hour of Daft Punk and Blue Man Group. I suppose an afternoon of Steel Pulse could potentially turn the unit off—but someone else will have to undertake that experiment. (Thermal shut-down occurs at 176° F, quite a bit above the maximum operating temperature I experienced.)

Paradigm Electronics, which acquired the Anthem brand more than 20 years ago, introduced its first DSP room-correction technology in 2008. The software has evolved continuously since then, but at two junctures the product was felt to have changed enough to warrant a new designation. The first was in 2014, when ARC became ARC-2; the second was in May of 2019, with the release of ARC Genesis after a lengthy period of beta-testing. I downloaded the latest build of the new version for this review.