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Pioneer QX-9900

Four Channel Receiver with Matrix Decoding (1972-74)

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Pioneer QX-9900


Four channel finally comes of age with this versatile receiver from Pioneer, an outstanding achievement unusual in both capability and tremendous power output.

Featuring a unique matrix decoding circuit, that reproduces all regular matrix records, as well as a second type of decoding circuitry for the SQ matrixed type of records, the QX-9900 is simply the most complete receiver for four channel now available today.

In addition to it's matrix decoding capability, the QX-9900 may also be used for discrete four-channel reproduction as well as more conventional two-channel reproduction.

It's FM tuner characteristics are equally superb, distinguished by excellent sensitivity, a wide linear FM dial scale, and superb selectivity.

Carefully engineered to typically high Pioneer standards, the QX-9900 will give you many years of faithful musical reproduction.

It moves you into the fascinating sound world of four channel and even a bit beyond.


Tuning range: FM, MW

Power output: 33W/ch (stereo), 28W/ch into 8Ω (quadraphonic)

Frequency response: 10Hz to 20kHz

Total harmonic distortion: 0.5%

Damping factor: 50

Input sensitivity: 3.8mV (mic), 2.9mV (MM), 200mV (DIN), 200mV (line)

Signal to noise ratio: 75dB (MM), 85dB (line)

Output: 200mV (line), 35mV (DIN)

Speaker load impedance: 4Ω to 16Ω

Semiconductors: 8 x FET, 4 x IC, 113 x transistors, 62 x diodes

Dimensions: 560 x 170 x 430mm

Weight: 21.3kg


Related Catalogues

Four Channel Stereo

Hi-Fi Stereo

HiFi Stereo Components

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Reviewed Feb 27th, 2018 by Ellies Fashions

We own a QX-9900 and like it a lot! A question for the quad aficionados here...

We see a big similarity between our Pioneer Quad QX-9900 and our larger Akai AS-980. The similarity is striking. The Pioneer quads of that era all look different than the QX-9900 but the other Akai Quads of the period resemble both the Pioneer QX-9900 and our Akai AS-980...

So, our question if anyone can answer it is was the Pioneer QX-9900 made by Akai of Pioneer components but none the less was made by Akai? The receivers are vastly different inside and Akai's documents are vague in comparison with Pioneers so there are differences...

Still, we think Akai made the Pioneer QX-9900 for Pioneer back in the day? True or False?

Reviewed Sep 27th, 2016 by coolsc21

Even forty years after the last production, the unit is impressive both in sound and look.

Reviewed Aug 22nd, 2014 by marceloxxx007xxx007

Very nice blue panel , but to be perfevt had to increase the power amplifier to minimum 60 watts x 4 ...And stereo to 80 watts....His construction is top superior in details...Very nice...



jmars1974's picture

re: QX-9900

Anyone familiar with this units meter function? My output meters are intermediate or not working at all.
What board controls these and what components are problematic?

re: QX-9900

My unit has sticky meter stops. I can free them by increasing the sensitivity of the meters and turning up the volume. Be careful though not to damage the meter coils with too much voltage for too long. The correct fix is to disassemble the meters and clean the stops with lacquer thinner or contact cleaner.



Guys I like your site very much ,so helpful.
Any available schematic diagram on this unit? Pioneer QX-9900.
Thanks a lot and more power,


re: QX-9900

I have an original Pioneer QX9900 schematic contact me


re: QX-9900

hi john i see you have schematics qx9900;is there any chance of a copy.regards norman

re: QX-9900

A copy of both the front an back of the original schematics has been posted here on the website. If you want me to email you a copy contact me

This website is not affiliated with or sponsored by Pioneer. To purchase QX-9900 spares or accessories, please contact the company via their website or visit an authorised retailer.