Product Review (April 2002) - Rotel RMB-1075
THX-Ultra Certified Five-Channel Power Amplifier


Rotel is one of those companies that is recognized for their affordable audiophile products. The RMB-1075 is no different, offering a moderately priced five-channel THX-Ultra certified power amplifier rated at 120 watts per channel into 8 ohms or 200 watts per channel into 4 ohms. Better yet, this amplifier has a flat frequency response out to 100 KHz, making it ideal for high bandwidth formats such as SACD and DVD-Audio. This attractive amplifier has large finned vertical heatsinks on both sides of the front panel with LED indicators for power as well as individual channel status in the event the protection circuits activate. Internal heatsinks also occupy both sides of the chassis, each of which contain two channels of amplification. The remaining channel uses the front panel heatsink. A large power switch is located in the lower center of the face of the unit. During power on, relays are used to delay the activation of the input signal to prevent speaker thump.

The RMB-1075 uses one large 1,500VA toroidal power transformer. Power rails are filtered with eight 10,000uF British-made slit-foil capacitors. Each output channel uses four bipolar transistors (two 2SA1492s and two 2SC3856s) for a total of 20 output devices, each rated at 130W/15A.

The rear of the unit has five gold-plated RCA connectors along with a DB-25 input connector. Speaker outputs use color-coded 5-way binding posts for maximum convenience. The 12 volt trigger input with pass-thru capability is a great feature enabling a preamp to activate the power. The non-grounded detachable power cord was a nice addition to this product.

Setup
Our setup had a Parasound AVC-2500u THX-Ultra A/V controller with the 12 volt outputs used to trigger the amplifier. UltraLink Platinum Ultima MkII interconnects were used throughout the system. The speaker system consisted of three Miller & Kreisel S-150THX speakers across the front channels and a pair of SS-250 Tripole® for the surround channels. Each of the five channels present 4 ohms of nominal impedance to the amplifier making it a fairly difficult load to drive. We used a Sony DVP-NS900V for CD and multi-channel SACD source material. DVD-Audio was handled by our Kenwood DV-5900M DVD changer.

We drove our speakers rather hard to see what limitations may exist with this amplifier, but even at relatively high levels, the performance was excellent. Detailed transients were evident in many of our high resolution recordings as well as excellent imaging qualities. The amplifier worked very well with our A/V controller, which uses a THX Linkwitz-Riley crossover set at 80Hz. The subwoofers begin to take over below this frequency. The transition between the main channels and subwoofers was smooth and without any noticeable voids or bumps in the bass response.

The Rotel RMB-1075 performed amazingly well in our system, especially given the list price of under $1000. The THX-Ultra badging ensures adequate drive capabilities for most speaker systems. The looks and performance of this multi-channel amplifier proves that great sound quality can be had by those on a budget.
- Kevin Nakano

 
Review System

Preamplifier/Processor: Parasound AVC-2500U THX-Ultra DTS/DD Preamp/Processor
Front Speakers: Miller & Kreisel S-150THX (L+R) and S-150AC (Center) Speakers
Rear Speakers: Miller & Kreisel SS-250 Tripole® Surround Speakers
Subwoofer: Two Miller & Kreisel MX-350THX MkII THX-Ultra Push-pull Subwoofers
Room Treatments: Echo Buster panels and Bass Buster towers
Display: Pioneer Elite PRO-610HD 58-inch HD-Ready TV (ISF calibrated)
Scaler: Focus Enhancements CenterStage2
Set-top Box: RCA DTC100 HDTV/DSS Satellite Receiver
DVD/CD/SACD Player: Sony DVP-NS900V DVD/CD/SACD Player
DVD Audio/Video Player - Kenwood Sovereign DV-5900M 400-Disc DVD Changer
Laserdisc Player : Pioneer Elite CLD-99 and CLD-D704 Laserdisc Players
A/V Cables: Ultralink Platinum and Advanced Performance Series Cables
Audio Analyzer: Sencore SP295 Audio Analyzer
Video Generator: Sencore VP300 SDTV/HDTV Video Pattern Generator
Color Analyzer: Sencore CP288 ISF Certified Color Analyzer

 

Review at a glance
Rotel RMB-1075

Features

  • THX-Ultra certification.
  • Large 1,500 VA Toroidal transformer.
  • Eight 10,000 µF British-made Slit Foil capacitors.
  • 20 high-current output devices, 4 per channel.
  • Gold plated RCA and DB-25 input connectors.
  • Separate 12 volt “trigger ” input and output jacks.

    Specifications

  • Frequency Response: 15Hz - 100kHz +0.5dB, -3dB
  • DIN Power Output (1 kHz, 1%): 5x200 watts per channel at 4 ohms
  • Five-Channels rated at 120 Watts per channel at 8 ohms
  • Five-Channels rated at 200 Watts per channel at 4 ohms
  • Total Harmonic Distortion (20 Hz - 20 kHz, 8 ohms): 0.03% maximum
  • Damping Factor (20 - 20,000 Hz, 8 ohms): 180
  • Signal to Noise Ratio (IHF A network): 116dB
  • Input Impedance/Sensitivity: 1.0 V / 33 kOhms
  • Power Requirements: 115 volts, 60 Hz (U.S. version), 230 Volts, 50 Hz (European version)
  • Power Consumption: 800 Watts

    Company Information
    Rotel of America
    54 Concord Street
    North Reading, MA 01864-2699
    Phone: 978-664-3820
    Fax: 978-664-4109

    Source: Manufacture loan
    MSRP: $999
    Size: 16.93" x 7.4" x 15.59" (WxHxD)
    Weight:
    37.4 pounds
    Warranty: 5 year parts and labor

    URL: www.rotel.com

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