What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

H.H. Scott '59

Rotel RT-2100 (1978)


As obvious as it may seem, a tuner's true worth is determined by the accuracy of its tuning. Both of Rotel's 2000 series tuners ensure absolute precision by using a quartz crystal oscillator lock system.

Rotel's quartz lock system automatically compares the precise 10,7 MHz emaneting from the oscillator with the approximate 10,7 MHz of the intermediate frequency (IF). Should there be a discrepancy a positive or negative signal is accordingly emitted by the phase comparator which passes through the low pass filter (LPF) and serves to lock the local oscillator.

Touching the tuning knob unlocks the quartz control. Releasing one's hand from the tuning knob automatically activates the quartz lock circuit which then maintains the station selected. Once tuned stable reception is quaranteed and drift is eliminated regardless of changes oscillation is locked.


Touching the tuning knob causes the quartz lock to unlock upon register of induction voltage. This then causes the local oscillator frequency to become linear and when the tuning pointer approaches the desired broadcasting signal or within ±60 kHz of it the side indicator lamp goes on. When the tuning pointer further moves to within ±8 kHz of the desired station (capture range) the center green indicator light goes on. Releasing the tuning knob at this point causes the tuning lights to extinguish and the quartz lock indicator light on the right side to go on signifying that the quartz lock is operating.


Rotel uses a linear-frequency precision 5 gang variable capacitors. The RT-2100 has a 3 Dual-Gate MOS FET stages, (while RT-2000 has one Dual-Gate MOS FET), both employing the best low-noise components, with resultant superior interference reiection capability as well as having a positive effect on cross modulation interference. The intermediate frequency band is divided into 2 stages, WIDE and NARROW, which ensures superior sound quality under varying conditions of reception, and the linear phase filter aids in low distortion and superior stereo separation.


Tuning is made amazingly simple and accurate by employing a digital station indicator that can be read at a glance in conjunction with the quartz PLL lock. The signal indicator also uses an easy to see yet beautifully designed LED display system.


The multipath phenomenon in FM reception, similar to double images on television , can adversely affect sound fidelity. With the Multipath switch "ON" it is possible to select the optimum position for an antenna. The degree of multipath interference can be checked with the digital signal indicator on the RT-2100 ( and the signal meter on the RT-2000).


In order to improve frequency characteristics in the MPX section, Rotel has paid particular attention to the cut off of the pilot signal (19 kHz) and weakening of the carrier signal (38 kHz). By using LC block filters, high frequency range drop is minimized and a wide range is guaranteed, with the result that rich sound reproduction is possible. The PLL IC is employed to assure constant high stereo separation at low distortion for wide dynamic range.


IF (intermediate frequency) is the front end output (unified at 10,7 MHz for FM) resulting from the difference between the broadcasting signal received and the oscillator frequency. Rotel makes it possible to select between two options Wide or Narrow. When reception is weak, use of a narrow IF band can result in superior selection.


When receiving a Dolbylized FM broadcast, turning the function selector on the RT-2100 to the Dolby FM position activates the Dolby NR circuitry and enables enjoyment of a clear sound at lower distortion without loss of frequency response.


Push the REC CHECK button activates a 400 Hz tone signal from the built-in circuitry. Fail-safe recording is ensured if the tape deck recording level is then set (usually 0 dB) on this tone to prevent overloading by the broadcast signal.


Rotel's Hi-Blend switch creates a faithful and easy-to-listen-to reproduction by cutting out unwanted high frequencynoise with minimum loss for stereo separation and frequency response.


Effective selectivity (IHF): narrow: 80 dB

Frequency characteristic: 30 Hz - 15 kHz ±0.2 dB

Stereo separation: 47 dB (1 kHz)

Capture ratio: 1 dB

Image stonewalling ratio: 115 dB

IF stonewalling ratio: 115 dB

Sensitivity (IHF):

stereo: 36 dBf/35 microvolts (S/N 50dB)

mono: 9.3 dBf/1.6 microvolts (S/N 26dB)

S/N ratio (IHF):

stereo : 75 dB

mono : 80 dB

THD wide:

stereo : 0.07%

mono : 0.05%

THD narrow:

stereo : 0.2%

mono : 0.15%

Muting: 5 microvolts

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

Weight: 7,5 kg

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