Rotel RB-1552 MkII Stereo Power Amplifier

A Power Amp That "Conveys All the Music You Could Want"

The Rotel RB-1552 MkII stereo power amplifier is built upon the same platform as the RB-1582 MkII with only a slightly smaller power output capability at 2 x 130 watts. It is engineered to be powerful and robust, yet able to extract every last nuance out of even the most complex musical score.

Notable features of the amplifier include independent left and right power rectification stages and decoupling. The layout is essentially a mono block design. Further evidence of design over-spec is in the selection of premium “slit-foil” capacitors. Input options are balanced XLR or unbalanced RCA connectors.

The RB-1552 MkII stereo amplifier has been engineered to provide high-resolution audio performance, yet it is very affordable, as has been the tradition with Rotel electronics for over 50 years.

"Modestly priced audio products may not be able to produce the 'absolute sound,' but the best of them can fully deliver the heart of the high end," reports Alan Taffel in The Absolute Sound magazine. "Rotel's 1570/1552 stack falls decisively into this category, forming an incredibly affordable, versatile system that conveys all the music you could want – and more – with very few trade-offs. Rotel is back, my friends. And it is good."

Extremely High Performance Power Supply

The RB-1552 MkII's high-end performance begins with an extremely large toroidal transformer using special “slit foil” capacitors to provide completely stable power to the output stage. Slit foil capacitors have the ability to charge and discharge extremely quickly, thereby ensuring signal fidelity during orchestral crescendos or repetitive kick-drum impacts, for example.

Dual Monoblock Design

Both left and right channel construction are laid out in a dual monoblock design (after the toroidal transformer) and all grounding is terminated in a star pattern on a copper grounding plate to ensure low signal to noise. The powerful output stage is a discrete design that consists of high current bipolar transistors.

Input and Output Options

Input options consist of both balanced XLR and unbalanced RCA connectors. A toggle switch in the rear panel selects the type of input signal to use. The RB-1552 MKII has four pairs of color-coded speaker binding posts, two for each channel – allowing you to run two pairs of speakers at the same time, if you wise. These connectors accept bare wire, connector lugs, or dual banana type connectors. (Note that there is no speaker selection switch, so both pairs of connected speakers will play if you use two pairs.)

Protection Circuitry

The RB-1552 MKII features thermal and over-current protection circuits that protect against potential damage in the event of extreme or faulty operating conditions. Unlike many designs, these protection circuits are independent of the audio signal and have no impact on sonic performance. Instead, the protection circuits monitor the temperature of the output devices and the current they are handling and shut down the amplifier if operating conditions exceed safe limits.

Most likely, you will never see this protection circuitry in action. However, should a faulty condition arise, the amplifier will stop playing and the LED indicator on the front panel will light up.

The RB-1552 MkII stereo power amplifier is yet another outstanding example of Rotel’s Balanced Design Concept and will form the heart of a very impressive stereo or home theater system for years to come.

Overview

• 2 x 130 watts of robust power
• Class AB amplifier design
• Rotel Balanced Design Concept circuitry
• Powerful output stage with high current bipolar transistors
• Extremely large toroidal transformer
• High quality slit foil capacitors made in Britain
• Two pairs of speaker binding posts
• XLR and RCA inputs
• Thermal and over-current protection circuits
• Rack ears included
• Trigger ON/OFF Mode Selector

• 1 x pair balanced XLR inputs
• 1 x pair unbalanced RCA inputs
• 2 x pairs speaker binding posts
• 12 Volt Trigger Input and Output

• Continuous Power Output: 130W/Ch (All channels driven, 8Ω)
• Total Harmonic Distortion (THD)(20Hz–20kHz): <0.03%
• Frequency Response: 10Hz - 100kHz ±0.5dB
• S/N Ratio (IHF "A" Weighted): 120dB
• Gain: RCA: 26.5dB; XLR: 22.5dB
• Intermodulation Distortion (60Hz:7kHz, 4:1): <0.03%
• Damping Factor: 450
• Speaker Impedance: 4Ω minimum
• Input Sensitivity: Line Level Inputs (RCA): 1.5V; Line Level Inputs (XLR): 2.5V
• Input Impedance: Line Level Inputs (RCA): 12kΩ; Line Level Inputs (XLR): 100kΩ
• Power Consumption: 400W
• Standby Power Consumption: 0.5W
• Dimensions (W × H × D): 17" × 5.7" × 13.4"
• Weight: 27 lbs.

"Strings are properly rich, bass is weighty, and the piano possesses a lovely round tone. Microdynamics and tiny tempo variations come through clearly, allowing the listener to hear the give and take among the players."

"Modestly priced audio products may not be able to produce the 'absolute sound,' but the best of them can fully deliver the heart of the high end. Rotel's 1570/1552 stack falls decisively into this category, forming an incredibly affordable, versatile system that conveys all the music you could want – and more – with very few trade-offs. Rotel is back, my friends. And it is good."

- Alan Taffel, The Absolute Sound magazine, April 2014