SONY STR-6550

Commentary

This FM/AM receiver has improved overall performance while maintaining its usability as a receiver.

A MOS type FET is used for the front end of the tuner section.
Sony has also replaced the LC-type filters used in this class of receivers with Sony's proprietary solid-state filters.
In order to avoid unpleasant noise during tuning operation from station to station, a new concept of gain allocation is introduced, and comfortable operation with muting is enabled.

Solid state filter is also used for the AM part.

The amplifier section uses silicon transistors developed for audio applications to reduce distortion that makes sound muddy.

It can also be used as a stereo loudspeaker device by using either two microphones or a one point stereo microphone.
A single microphone can emit sound from both left and right speakers.
In addition, there is a mixing device that can mix the sound of the microphone with the sound of the record, FM broadcast, and the sound of the tape. By using this device, you can edit the tape while adding narration.
You can also fade the microphone in and out.

Equipped with a speaker selector switch that can be used by switching between two sets of speakers.

It is equipped with a loudness switch.

Since the preamp section and main amplifier section can be used separately, it can be upgraded to a multi-amplifier system.

Equipped with an effective high-filter switch to cut out high-frequency noise.

The character displayed on the dial screen changes in conjunction with the function switch.

Model Rating

Type	FM stereo / FM-AM receiver
Circuit system	Quasi complimentary service SEPPP OTL circuit
FM Tuner Section
Antenna terminal	300 Ω equilibrium
Sensitivity	1.8 μ v (IHF) 1.4 μ V (S/N : 30 dB)
Image interference ratio	55dB
IF interference ratio	90dB
Spurious interference ratio	78dB
AM suppression ratio	55dB
Capture ratio	1.5dB
Selectivity	70dB(IHF)
Signal-to-noise ratio	68dB
Frequency characteristic	30 Hz to 15 kHz, + 0 -2dB
Distortion Factor (400 Hz, 100% Modulation)	mono:0.3% stereo:0.8%
FM stereo separation	35 dB or More (1 kHz)
<AM Tuner Section>
Antenna terminal	Built-in bar antenna With External Antenna Terminal
Sensitivity	Bar antenna : 48dB/m External antenna : 30 μ V
Image interference ratio	55dB(1000kHz)
IF interference ratio	40dB(1000kHz)
Signal-to-noise ratio	50dB
Distortion factor	0.8%
Amplifier Unit
Output	Dynamic Power (IHF) : 54W (8 Ω) 61W (4 Ω) Effective output (1 kHz, half-channel) : 25/25W (8 Ω) 25/25W (4 Ω) Effective output (1 kHz, both channels) : 20W + 20W (8 Ω) 22W + 22W (4 Ω)
Output Level / Impedance	Recording Terminal : 250mV/10k Ω [REC/PB] Output : 30mV/82k Ω Headphone Output : 8 Ω ~ 10k Ω Speaker terminal : 4 Ω ~ 16 Ω
Preamplifier / power amplifier terminal	Preamplifier output : 0.5V/5k Ω Power amplifier input : 0.5V/100k Ω
Harmonic distortion factor	0.8% or Less (Rated Output) 0.1% or Less (at 1W Output)
Cross modulation distortion factor (60Hz:7kHz=4:1)	0.8% or Less (Rated Output) 0.1% or Less (at 1W Output)
Frequency characteristic	Phono : RIAA standard AUX, Tape, Rec/PB : 30 Hz to 40 kHz, + 0 -3dB
Input Level / Impedance (at rated output)	Phono Terminal : 2.5mV/47k Ω My Kujac : 2.0mV/47k Ω AUX Terminal : 250mV/100k Ω Tape Terminal : 250mV/100k Ω [REC/PB] Input : 250mV/100k Ω
Signal-to-noise ratio	Phono Terminal : 60 dB AUX terminal : 70 dB Tape Terminal : 80 dB [REC/PB] input : 80 dB My Kujac : 60 dB
Damping factor	25 (8 Ω)
Tone control	Treble : 10 kHz, ± 10 dB Bass : 100 Hz, ± 10 dB
High filter	6dB/oct, 5 kHz or more
Loudness switch (at -30dB)	50 Hz, + 6 dB 10 kHz, + 4 dB
<General>
Semiconductor used	Transistor : 44 FET:1 Diode : 27
Pwer	100 VAC, 50Hz/60Hz
Power outlet	300W, non-interlocked : 1 system
Power consumption	63W
External dimensions	Width 434x Height 144x Depth 345 mm
Weight	8.5kg
Attachment	Feeder antenna Fuse 2Ax2