Sony ST-2950SD tuner

Features

FET front-end

New,computer-designed uni-phase IF filters

Phase-Locked-Loop IC stereo MPX stage

Dolby noise reduction system for decoding Dolbyized FM broadcasts, and Dolby Indicator light.

Center station and signal strength tuning meters

Smooth flywheel tuning action

Wide, frequency linear dial calibrastion

FM interstation muting

FM discriminator output for future 4-channel FM

High blend switch

Automatic mono/stereo switching, and stereo indicator light

Wooden side panels included

Sony's new ST-2950SD tuner is priced in the udget range, but is built with advanced electronics that mean high performance. For a very modest expenditure, FM listeners can enjoy the quality sound of the ST-2950SD, as well as the convenience of a built-in Dolby decoding system for FM.

FM Section

The unit's FM front-end electronics, with FET desoign, yield high sensitivity and a high interference rejection capabaility.

The intermediate frequency stage

utilizes Sony's new uni-phase (F filters, providing high selectivity and, at the same time low audio distortion.

And for excellent FM stereo, the multiplex stageis  built with a Phase-Locked- Loop IC, providing low distortion decoding and high stereo separation.

At least 35 dB of separation is maintained at high and low ends of the frequency spectrum, while 40 dB is achieved at midrange frequencies.

Overal FM performance rating include a capture ratio of 1,0 dB, an S/N Ratio of almost 70 dB in stereo and more than acceptably good distortion figures.

For listeners who want an uncomplicated means of taking advantage of Dolbyized FM programs, the ST-2950 SD provides simple, one-step decoding.  When stations send out Dolbyized broadcasts,

all that's required for decoding is to press the unit's Dolby button - no need to use an-add on noise reduction unit, and no need to be concerned about changing FM de-emphasis.

AM Section

A triple AM AGC circuit is just  one aspect of AM design that makes the ST-2950SD produce far etter than everage AM-only programs without the usual levels of irritating interference. 

Tuning

Tuning the ST-2950SD is simple and accurate, with ultra-smooth flywheel tuning action, frequency linear dial calibration and highly readable tuning meters to help zero in on the station. FM interstation muting cuts out noise, and a clea, human-engineered front panel provides ease of use - in both tuning and control.

Specifications:

FM Tuner Section

Antenna Terminals:  300 Ω (balanced), 75 Ω (unbalanced)

Usable Sensitivity (IHF '58):  2,0 µV

50 dB Quieting Sensitivity:

Mono :  4,0 µV

Stereo :  50 µV

Signal-to-Noise Ratio:

Mono :  73 dB

Stereo :  68 dB

Capture Ratio:  1,0 dB

Selectivity:  50 dB

Image Rejection:  45 dB

IF Rejection:  90 dB

Spurious Rejection:  75 dB

AM Suppression:  54 dB

Total Harmonic Distortion:

Mono :

At 100 Hz :  0,2%

At 1 kHz :  0,2%

At 10 kHz :  0,2%

Stereo:

At 100 Hz :  0,3%

At 1 kHz :  0,3%

At 10 kHz :  0,6%

IM Distortion:

Mono :  0,2%

Stereo :  0,3%

Frequency Response:  30 Hz - 15 kHz (+0.5 -1,5 dB)

Stereo Separation:

At 100 Hz :  35 dB

At 1 kHz :  40 dB

At 10 kHz :  35 dB

RF Intermodulation:  60 dB

Subcarrier Product Ratio:  60 dB

SCA Suppression:  60 dB

AM Tuner Section

Antenna:  Built-in ferrite bar antenna w/terminal for ext. Wire

Sensitivity:  250 µV/m (w/built-in antenna); 100 µV (w/ext.antenna)

Selectivity:  35 dB at 10 kHz

Signal-to-Noise Ratio:  50 dB at 50 mV/m

Image Rejection:  40 dB at 1,000 kHz

Total Harmonic Distortion:  0,5% at 50 mV/m, 400 Hz

General Section

Output Level/Impedance (at 100% modulation)

Audio (Fixed):  750 mV/5 k Ω

Discriminator:  150 mV/2,5 k Ω

Semiconductors:  4 ICs, 1 FET, 17 Transistors, 14 Diodes

Power Requirement:  AC 120V, 220, 240 V 50/60 Hz

Power Consumption:  26 W

Dimensions (W x H x D):  390 x 145 x 310 mm (15-3/8" x 5-3/4" x 12-1/4")

Weight:  6 kg (13 lbs 4 oz)