Revox A720
DIGITAL FM TUNER PRE-AMPLIFIER

SPECIAL FEATURES

Tuner Section

1.

Quartz stabilized frequency synthesizer (channel raster oscillator). Very stable; no frequency drift.

2.

Five digit frequency display

3.

Pre-set instant tuning for five stations

4.

Stepped manual tuning. Tuner will stop on exact frequency when tuned to assigned channel.

5.

Endless tuning scale. Scale range from 87.00 to 107.95 MHz. Tuning above 107.95 MHz instantly steps to bottom of scale (87.00).

6.

Meters for signal strength and frequency 'lock in'.

7.

Switchable noise filter for fringe area reception stereo stations. Improves signal to noise without sacrificing frequency response.

8.

Digital FM demodulator (pulse counter)

9.

Stereo Decoder with 76 kHz oscillator, integrated frequency divider and 'phase-locked loop' frequency.

10.

Phase-linear passive IF filter.

11.

Five stage integrated wide-band limiting amplifier.

12.

Remote control facility

13.

Antenna sockets for coaxial cable (BNC) and turn-lead cable (DIN).

Audio Section

1.

Volume and balance control by means of sliding type faders.

2.

Stepped independent tone controls for bass, presence and treble

3.

Two headphone outputs on front panel. The headphone amplifier includes a specially development 'binaural network'. When switched into the circuit low frequency signals are distributed to both channels, with an appropriate time delay providing true stereophonic listening even with headphones.

4.

Inter-connecting facilities for two tape recorders. Transfer between recorders available without further connections or record-off tuner on one while playing back on the other. Off-tape monitoring for both tape recorders.

5.

Additional tape output on front panel

6.

Two stereo phono and one stereo auxiliary input

7.

Pre-set level controls on all five inputs (left and right channels) screw driver adjustable.

8.

High and low pass filters effective on all inputs.

9.

Loudness switch to obtain physiological loudness control.

10.

Two switchable stereo outputs (for two independent stereo amplifiers).

11.

Remote control facility for volume, balance and loudness control (available shortly)

12

Remote switching of supply to power amplifiers.

Technical Data: Digital FM Tuner A720

Tuning Range

87.00 MHz - 107.95 MHz,
420 channels in 50 kHz steps

Tuning Accuracy

0.005%

Sensivity

Mono 1 ÁV, stereo 10 ÁV, measured at the 60 ohm antenna input for a signal to noise ratio of 30 dB with reference to 15 kHz deviation

Station Selectivity

60 dB at a separation of 300 kHz

Image Response

100 dB

Spurious Response
(fE - 5.5 MHz)

100 dB

IF Suppression

100 dB

Capture Ratio

1 dB measured at 40 kHz deviation

Frequency Response

30 Hz - 15 kHz 1 dB

De-Emphasis

50 Ásec (or 75 Ásec)

Distortion

0.2% at 1 kHz and a deviation of 40 kHz
(Mono and Stereo L = R)

Signal to Noise Ratio

Mono 70 dB
Stereo 67 dB
referred to 75 kHz deviation

Stereo Crosstalk

40 dB at 1 kHz

Pilot-Signal and
Sub-Carrier Suppression

50 dB wide band measurement referred to 75 kHz deviation.

AM-Suppression

54 dB referred to 22.5 kHz deviation 30% AM / 400 Hz 1 mV/60 Ohm Antenna Input Voltage

Audio Output

1.5 V/ 40 kHz deviation on Out 1 + 2

Antenna

240 - 300 ohm DIN symmetrical
60 - 75 ohm BNC coaxial

Technical Data: Pre-Amplifier A 720

Inputs

AUX
TAPE 1
TAPE 2
PHONO 1
PHONO 2

100 mV
adjustable / 100 kOhm
adjustable / 100 kOhm
3 mV
adjustable / 50 kOhm

Outputs

OUT 1
OUT 2
TAPE
TAPE 1
TAPE 2
PHONES (2x)

1.5 V / Load not less than 10 kOhm
1.5 V / Load not less than 10 kOhm
200 mV / Load not less than 50 kOhm
200 mV / Load not less than 50 kOhm
200 mV / Load not less than 50 kOhm
3 V / Source impedance 100 ohm

Tone Control and Filter

BASS

TREBLE
PRESENCE
LOW FILTER

HIGH FILTER
LOUDNESS

80 Hz 8 dB (8 x 2 dB)
8 Hz
8 dB (8 x 2 dB)
3 Hz
8 dB (8 x 2 dB)
50 Hz / -3 dB; 25 Hz / -18 dB
10 kHz / -3 dB; 20 kHz / -10 dB
(-40 dB) 100 Hz / +14 dB; 10 kHz / +5 dB

Distortion

0.1% at an output level of 1.5 V

Intermodulation

0.1% at an output level of 1.5 V

Frequency Response

20 Hz - 20 kHz 1 dB

Signal to Noise Ratio

AUX, TAPE 1 + 2: 85 dB
PHONO 1 + 2: 65 dB

Crosstalk

60 dB at 1 kHz

 


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