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Pioneer SX-550

Stereo AM/FM Receiver (1976-78)

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Pioneer SX-550


The Pioneer SX-550 is a 20 watt AM/FM stereo receiver featuring FM muting, two tape monitors and provision for 2 pairs of speakers.


Tuning range: FM, MW

Power output: 20 watts per channel into 8Ω (stereo)

Frequency response: 10Hz to 60kHz

Total harmonic distortion: 0.3%

Damping factor: 25

Input sensitivity: 7.5mV (mic), 2.5mV (MM), 150mV (DIN), 150mV (line)

Signal to noise ratio: 70dB (MM), 90dB (line)

Output: 150mV (line), 30mV (DIN)

Speaker load impedance: 4Ω (minimum)

Semiconductors: 3 x FET, 5 x IC, 28 x transistors, 21 x diodes

Dimensions: 448 x 141 x 307mm

Weight: 9.4kg

Accessories: FM T-type antenna

Year: 1976


schematic (HG)  English -

instruction/owners manual   English - Outback Bub

schematic (KU/KC)  English - elbisreverri

schematic (HG alt scan)  English - Jasper99

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Reviewed Oct 17th, 2016 by racherry

Cleaning out the attic and found my SX-550. Cleaned it up cosmetically, opened it up and cleaned the switches and pots. Found a small rectifier in the box marked good when I had it fixed over 35 years ago. Plays beautifully. Took down my Altec Lancing speaker set on my computer and hooked this thing up with a couple old JBL 2500 bookshelves. Could not be happier. Really great sounding amp.

Reviewed Aug 11th, 2016 by Auzzy3130

My sx-550 still sounds very good and all functions work despite it never having any maintenance (yet). I have several of these 70s low power pioneers and I love them for listening with my sennheiser headphones.

Reviewed Sep 16th, 2015 by crazyhifi7070

This was my first receiver as a kid. It always thumped my speakers when turned on. I didn't have very good speakers anyway. I bought it new. Did I get a bad one or did all the SX-550s do that? I had it for many years and it survived many moves. It finally gave up the ghost and I put it to the curb. I know I should have checked it out but this was before the silver Pioneer craze and it was a low output unit. Really happier with 30 and 45 Watt units more than 20 Watt ones. I'd be interested to hear if the Thumping is common for this model? Please comment. Thanks.

Reviewed Apr 06th, 2015 by jgossman

I have a very nice little unit that I've restored and mostly repaired. At this point it's ready to turn over to the purchaser except I cannot get the FM reception to work at all. I've replaced the JFET RF receivers as well as the 1137 and 1138 IC's. All the associated passive components measure withing spec. Any ideas?

Reviewed May 12th, 2013 by JohnnyCrash8

Awesome little unit! Sounds beautiful!



re: SX-550

Mine doesn't thump at switch-on, and I can see from the schematic that there is an anti-thump circuit just before the power amp section. Sounds like CrazyHiFi7070 had a fault in that circuit.

re: SX-550

Nice sound at good price

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