The new Anthem STR Integrated Amplifier

There’s much to be said for integrated amplifiers and while separates have long dominated high-end audio, an increasing number of audio brands are now delivering integrated products that bundle a preamp and power amp, but sometimes add digital inputs of various flavours, phono stages, bass and treble controls (long on life support in audiophile gear), and more into one offering.

The new Anthem STR which is now available in all black or all silver is one product that is amplifier that is proving popular.

At 18 kilo, it’s moderately light and cool-running for a class-AB amplifier specified to output 200Wpc into 8 ohms, 400Wpc into 4 ohms, or 550Wpc into 2 ohms across the entire audioband at less than 1% total harmonic distortion (THD).

The STR’s power-amp stage is built around a single large, toroidal transformer, with oversize filter capacitors and load-monitoring circuitry for optimal performance. Its 2-ohm rating should allow the STR to work without breaking a sweat with virtually any modern speaker, some of which have impedances that can dip that low— or even lower—in at least a narrow part of their frequency range.

Apart from ARC, the Anthem STR offers more than the usual complement of features for an integrated amp. There are five analogue inputs (four sets unbalanced, one set balanced); digital conversion and processing can be bypassed with each of them. The six digital inputs include two TosLink optical, two coaxial, and one AES/EBU, all of which support inputs of up to 24-bit/192kHz. An asynchronous USB Type B digital input accepts PCM up to 32/384, and DSD at 2.8 or 5.6MHz. All internal digital processing is performed in PCM at 32/192, so all digital inputs are converted to that resolution, including DSD and, if desired, the analogue inputs.

There’s also a pair of unbalanced, fixed-level RCA preamp outputs for connection to a headphone amp, plus separate, variable-level, unbalanced preamp outputs, in the unlikely event that you choose to later add an outboard amp.

The STR has two phono inputs, one each for moving-magnet and moving-coil cartridges. There’s an Ethernet port for configuring ARC (the STR itself is not Wi-Fi-capable); alternatively, a mini USB B port can be used to set up ARC via a PC configured with the downloadable

ARC software.

An RS-232 input, a remote IR input, a 12V trigger, a single pair of high-quality L/R speaker terminals, and the ubiquitous IEC port for the detachable power cord fill out the spacious rear panel, which isn’t nearly as crowded as this description makes it sound.

The large display on the STR’s front panel shows the volume setting in numerals large enough to be read from across the room. When Info is selected, additional information appears: the operating input, ARC status (on or off), source resolution, and whether the output is in stereo or mono.

A single large knob to the right of the display can be used to adjust the volume in steps of 0.5dB, or to navigate the setup menus. There are also buttons for Power, Mute, and additional setup actions: Menu/Select, Previous, and Next. I rarely used any of the front-panel controls, preferring Anthem’s small, wireless, IR remotecontrol handset, which can be used to perform the identical functions. But some things, such as giving the inputs custom names, might be easier to do via the front panel.

Setup: Basic

The STR can be adjusted in a number of ways, with or without EQ. You can apply high- and low-pass filters for the main speaker and subwoofer(s) outputs at any frequency from 20 to 160Hz, and adjust the sub’s polarity and level, and the listening position.

You can choose to convert the analogue inputs to digital 32/192 or turn the conversion off and pass the analogue signal along to the amp section with no digital conversion.

Because I evaluated the STR full range, without a subwoofer, and only with a digital input, my setup was far simpler.

But with its ability to set up different inputs separately, use more than one setup for any input, pass along an analogue input unaltered or convert it to digital for processing, and more, the STR is exceptionally flexible.

All listening was done with my Monitor Audio Silver 10 speakers, and without subwoofer(s).

The Silver 10s were positioned about 6’ out from one of the short, bay-shaped walls of my room, spaced about 9’ apart and just slightly more than that from the main listening seat, and toed in so that their axes crossed just in front of the listener. I did all of my early listening without EQ, to evaluate the STR’s performance. I didn’t test the analogue inputs.

Listening: Without ARC

One of my favourite things about audio shows is discovering recordings that I might want to own for enjoyment, testing, or both. And despite the carcass that was the high-end audio portion of the 2018 Consumer Electronics Show, I did hear at least one such recording, in the Harman-Levinson-Revel room: Marcus Miller’s M2 (CD, 3 Deuces/Telarc CD-83534). It’s not the style of music I’d normally choose (jazz fusion, featuring Miller’s work on bass guitar and other instruments) but I ordered it when I got home. My enjoyment of it through the STR and my system was enormously helped by its superbly clean recording quality, with a smooth, silky, unexaggerated top end and solid imaging.

Listening: With ARC

I chose a ceiling of 500Hz; with ARC leaving untouched everything above that frequency, the speakers should still sound reasonably close to the speakers I use every day because I like them, minus most of the bass boom, tubbiness, and bloat that any room can cause. I suspect that most buyers of an STR will make a similar choice.

ARC is used in many other Anthem products, but the version included in the STR and Anthem’s new STR preamp is the most advanced, with some 50% more correction capability than even the best of them.

I set up ARC using Anthem’s recommendations, placing the mike at eight or nine different positions.

The differences I heard ranged from subtle to striking, depending on the recording played, and were only rarely inconsequential. Recordings with strong bass content saw the greatest improvement. Drums were tighter; closely spaced drum rolls, in particular, sounded more precise, each stroke more cleanly differentiated.

Conclusions

Most well-designed integrated amplifiers on today’s market go about their jobs as such products always have, without altering a system’s response in any significant way. That’s fine, and one of them might be just right for your system and room.

But despite the current popularity of analogue, particularly vinyl, there are things that can be done with digital processing, particularly when performed at high enough bit and sampling rates to satisfy the never-CDers, that we’ve never been able to accomplish in the analogue domain. In that regard, the Anthem STR is a watershed product worth serious consideration.

Highly recommended.

For the full in-depth review go to: https://www.stereophile.com/content/anthemelectronics-str-da-integrated-amplifier