Jeff Rowland Design Group Concerto and Model 201

By Michael Wong

June 2006

Concerto preamplifier $7999, with phono stage $9399
Model 201 mono power amplifier $9999/pr

Concerto preamp (click for larger image)

Back panel of the Concerto (click for larger image)

Model 201 mono power amplifiers (click for larger image)

Back panel of the 201 (click for larger image)

For the last couple of years Jeff Rowland Design Group have been on the Class D bandwagon, using Bang & Olufsen’s ICEpower amplification modules, a turnkey solution that doesn’t require vast modification to bring it’s performance up to high fidelity standards. Previously Class D was popular in less demanding applications like car audio subwoofery. JRDG cites the advantages as smaller physical size, higher efficiency, faster switching operation, lower RF and EMI radiation, full power supply regulation and elimination of power supply stress. Of the five power amplifiers in the current JRDG lineup, four employ ICEpower modules.

As with all JRDG products, this is exquisitely built. With its solid aluminium casework, the Concerto looks like a slimmed down version of the previously reviewed (now superceded) Concentra integrated.

Inputs and outputs

Six inputs are offered; three single-ended, two balanced and one balanced unity gain (for sound processors). All inputs are transformer coupled for quietness and immunity from interference. The review sample was fitted with the optional phono board. This has gain settings for moving magnet cartridges, high and low output moving coils, with loading options of 85, 100, 400 ohms or 47k ohms. The Concerto is also available as an integrated amplifier using the same preamp section with ICEpower modules onboard. In this form it replaces the Concentra integrated amplifier.

Each 201 is a tiny 66mm x 213mm x 292mm, weighing only 6kg. These are rated at 250w into 8 ohms, an amazing 500w into 4 ohms with 35A of peak current. The simple front panel features an engraved Rowland logo and small blue pilot light. They accept only balanced inputs. Speaker connection uses the unique Cardas sourced speaker binding post with a single U-shaped clamp to secure both legs of the speaker cable. Simple and elegant but limits users to spade connectors.

The Concerto and 201’s are designed to be continuously powered, consuming only 7 and 9 watts respectively, there is no standby mode and both have their main power switches located on the rear, along with detachable IEC equipped mains cables.

The six button remote control from the Concentra integrated completes the ensemble.

Plug and play

Setup was a simple matter of plug and play with the exception of the preamp input jacks placed horizontally in mirror image fashion, precluding the use of joint conductor interconnect cables. This wasn’t a problem except for my dedicated phono cable. Curiously, there was no documentation for the phono stage – nothing in the manual or on the company website. By pure luck it was ideally setup for my Shelter MC cartridge.

Despite the major shift in circuit topology the Concerto/201 shares a familiar house sound with the Concentra. There’s the same sweet, easy to listen to refinement. Good soundstaging and imaging. Good transparency and detail. A silky smooth sound, though slightly reticent highs. A warm midrange minus the rosy, tube-like glow that permeated the Concentra. Bass is big, with plenty of weight but could do with more extension, definition and snap. Dynamics are soft. There simply isn’t the authoritative sound expected of a 250W amplifier. Overall very listenable and pleasant but a little polite.

Freed from the 201’s, the Concerto revealed a finer performance; the highs seemed more extended and detailed. The sound was still on the soft side but dynamics were liberated and a good sense of rhythm and pace returned. The phono stage is even better. Greater immediacy, detail and speed could be easily heard - simply superb. The only gripe was that the bass was still sounding rolled off and a little sluggish.

The 201 clearly showed that it was the weaker partner. There wasn’t the wide open sound of the Concerto. It’s portrayal of dynamics was only average, missing the snap and vigour expected at this level. In the bass region the amp simply lacked the authoritative foundation to convincingly support the music.

I’m left wondering just how effective the ICEpower modules are and why narrow the bandwidth for the 201’s (-3dB at 10Hz, 70kHz; compare to the preamp’s 10hz–280kHz -3dB bandwidth and the Concentra’s -3dB at 0.1Hz, 160kHz).

Parts of it are excellent

With this JRDG combination we have a real curate’s egg. There’s the traditional unrivalled build quality, gorgeous cosmetics, ease of use, compact house friendly size of the power amps and generally a very listenable sound.

Of the pair, the Concerto preamp shines brighter, a very accomplished performer with a top class phono stage. The 201’s however proved to be less endearing. They are not bad amps but don’t push any performance boundaries, nor provide any substantive, sonic justification for using the ICEpower modules. While the Concerto and 201’s provided plenty of musical enjoyment, I would have loved to have tried the Concerto with a conventional JRDG power amp. As it stands, the 201 sounds like a work-in-progress.

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