Jeff Rowland Concentra w/ phono preamp card installed

4/8/24: Price reduced to $3100.  You pay shipping.

Features:

• Three balanced XLR inputs per channel plus three unbalanced (RCA) inputs per channel.
• Preamp Out in both balanced XLR output and unbalanced (RCA) outputs per channel.
• Tape input and output jacks allow tape recording from any source and monitoring of tape recorder output.
• Rear panel handles assist moving and transport of unit.
• Chassis and all chassis components, precision machined from 6061 aluminum plate, reduce distortion resulting from mechanical resonance and thermal instabilities.
• All operational functions under microprocessor control. Within five seconds of any function selected, the microprocessor reverts to a nonclocking “sleep” mode which eliminates any possibility of digital noise contamination.
• Non-multiplexed, zero electrical noise generating numerical display indicates volume level over entire range of 99.5 decibels.
• ‘Display off after five seconds’ option available for non-intrusive, low light listening environments.
• Dual range volume control allows large volume level changes when knob is rotated abruptly, yet permits precise small volume level changes when knob is rotated slowly.
• Optional plug-in phono cards (installed internally) convert Line Input 1 to high performance phono inputs. Four gain and input loading options standard for moving magnet and moving coil cartridge types.
• Full electronic and thermal protection modes guard against output overloads and short circuits.
• High current preamp outputs (balanced XLR and unbalanced RCA) allow simultaneous driving of external power amplifiers for subwoofers, vertical bi-amping, etc.
• Phono preamp cards installed; note that you have the option of switching them on/off.
• All inputs are transformer-coupled to provide maximum immunity from RF contamination and system ground loops and enhance compatibility with a wide variety of interconnected components.
• Speaker outputs are fully balanced to provide maximum sonic performance and immunity from RF contamination due to high output common mode noise rejection.
• Optical encoder type volume control maintains quiet, trouble-free performance and accuracy over entire lifetime of product. þ Six-function hand-held IR remote control.

There is no official info on the matter of output stage but from looking at the pictures it seems that the LM3886 integrated amplification circuits have been used instead of bipolar transistors. This integrated amplifier has created quite a stir in high-end circles. It has a modest 100 watts of power but just like all Rowland amps, it was much more powerful than these figures would lead you to believe.

All Concentras have a balance control which makes sense because they contain a version of the Synergy preamp inside. Using the remote control, the balance will work but this just is not indicated on the front panel. To reset the balance, press “Mute” for a couple of seconds.

Specifications:

Output Power Continuous RMS Watts
@ 8 ohms 100 watts
@ 4 ohms150 watts

Bandwidth
0.5 Hz to 160 kHz, -3 dB
Slew Rate
30 volts per microsecond

THD and Noise
Less than 0.06% at rated power

Damping Factor
60, 20 Hz to 20 kHz, 8 ohms

Output Current
16 amps continuous, 28 amps peak

Gain Structure
Preamplifier Section 14 dB
Amplifier Section26 dB

Volume Control Range
99.5 dB

Volume Control Resolution
0.5 dB ±0.05 dB over entire range

Input Impedance
36k ohm

Common Mode Rejection Ratio
Greater than 60 dB, 20 Hz to 20 kHz

Power Consumption
100 watts idle; 550 watts maximum

Inputs
Balanced Line3 per channel (XLR)
Unbalanced Line3 per channel (RCA)
Record1 per channel (RCA)
Unbalanced Phono (optional)1 per channel (RCA)

Outputs
Balanced Pre Out1 per channel (XLR)
Unbalanced Pre Out1 per channel (RCA)
Record1 per channel (RCA)
Speaker1 pair binding posts per channel

Dimensions
17.5 in (W) x 14.35 in (D) x 5.75 in (H) 44.5 cm (W) x 36.2 cm (D) x 14.6 cm (H)

Weight
50 lbs (23 kg)