Rotel RA-2020 (1978)

ROTEL RA-2020

Stereo INtegrated DC Amplifier

The integrated amplifier that has comprehensive refinements essential to excellent sound quality with ease of operation.

Less than 0.02% THD at max output of 60 watts per channel ( min.RMS both channels driven into 8 ohms from 20 to 20,000 Hz) - the component to match all others, with DC amplification, MC head amp, and no compromises on the quality inherent in Rotel's 2000 series.

DC CIRCUITRY

The RA-2020 uses DC amplifiers with excellent response at very low frequencies and makes maximum use of its DC circuitry design. As is becoming standard in precision equipment, Rotel's DC amps have eliminated all capacitors ( which give unwanted time constant) from the signal path and the negative feedback loop, stabilized the DC range and greatly improved transmission characteristics, enabling superior low frequency performance.

On the other hand, negative aspects of DC circuitry such as DC drift due to fluctuations in input and in power supply have been eliminated in the 2000 series by stabilizing the differential's mid-point electric potential, using circuit technology to achieve a DC balance, and securing an adeguate CMRR (Common Mode Rejection Ratio) value. As a result, the audio enthusiast is even free to enjoy the full dynamic range of organ music, with all its low frequency signals.

MC HEAD AMPLIFIER

The MC head amplifier built into the RC-2000 and RA-2040 use DC circuitry without capacitors in the input stage. The entry for signals from the MC (moving coil) cartridge is a FET differential with perfect symmetry to both negative and positive input signals. The output stage uses a pure complimentary push-pull circuit. This results in an input sensitivity/impedance value of 0,1 mV/33 ohms.

The RA-2020 both use a low noise FET differential amplifier for the input stage and a 3-stage parallel-coupled circuit for the output stage.

WIth a built-in MC head amp it becomes possible to enjoy music without having to use an external headamp or booster transformer even with a high performance MC type cartridge.

PHONO EQUALIZER

The RA-2020 uses a Class A differential amplifier in the first stage and push-pull IC circuitry in the output stage, ensuring ample phono overload capacity.

2-WAY TAPE DUBBING

Since the tape monitor switch and the recording selector function independent of each other, except for the RA-2020, dubbing between 2 tape decks is possible irregardless of what is being played through the amplifier (for the RA-2020, only either of tape decks can be played). Simple operation of the switch permits dubbing between 2 tape recorders in either direction.

TONE CONTROL

Use of a DC amp style tone control that eliminates coupling capacitors from the NF loop guarantees accurate reproduction even at low frequencies. Because of this circuitry design placing the Tone Defeat switch "ON" allows operation as a totally flat buffer amp. Control range is -10 dB +10 dB.

SUBSONIC AND SUPERSONIC FILTERS

Rotel 2000 series comes equipped with two filters - subsonic and supersonic - that eliminate unwanted components from the very high or very low frequency ranges inaudible to the human ear can have a negative effect on the audible range due to intermodulation and excessive base speaker cone excursions. The Rotel filters eliminate these at 12 dB/oct slope to provide perfect reproduction of the original sound.

Power amplifier part

Output power (both channel drive):

85 W/ch (4 Ω, 1 kHz)

60 W/ch (8 Ω, 20 Hz - 20 kHz)

THD: 0.02% (at the time of an output power 20 Hz - 20 kHz)

Cross modulation distortion: 0.02% (at the time of an output power 8Ω)

Frequency characteristic (1 W/ch; 8 Ω): 2 Hz - 160 kHz; +0 -3 dB

Input sensitivity/impedance: 1V/50kΩ

Dumping factor: 80 (1 kHz)

S/N ratio (IHF-A network short-circuit): 100 dB

Crosstalk (10 kHz): 57 dB

Equalizer part

THD:

Phono MAG : 0.006%

Phono MC : 0.008%

RIAA deflection (20 Hz - 20 kHz): ±0.5 dB

Input sensitivity/impedance:

Phono1 MAG : 2 mV/50 kΩ

Phono2 MC : 200 mV/150 Ω

Maximum permissible input (1 kHz, THD 0.5%):

Phono MAG : 200 mV

Phono MC : 5 mV

Preamplifier part

THD: 0.01% (at the time of an output power 20 Hz - 20 kHz)

Frequency characteristic: 5 Hz - 120 kHz

S/N ratio (IHF-A network):

Tuner, Aux : 92 dB

Tape monitor : 92 dB

Remains noise (at the time of a volume min): 8 mV; 100 dB

Input sensitivity/impedance:

Tuner, Aux : 150 mV/ 50 kΩ

Tape monitor : 150 mV/50 kΩ

Maximum permissible input (1 kHz, THD 0.5%): 15 V

Slew rate: 30 V/muS

Square wave rise time: 3 microS

Subsonic Filter: 15 Hz, 12dB/oct

Supersonic filter: 24 kHz, 12 dB/oct

Control width:

Bass: ±10 dB (100 Hz)

Treble: ±10 dB (10 kHz)

Max. power consumption: 450 W

Dimensions (W x H x D): 482 x 143 x 328 mm

Weight: 13 kg