Pioneer QX-949

The Pioneer QX-949 is one of Pioneer’s larger quadraphonic receivers and was top of the line when it was introduced in 1973. This was mainly due to the fact that it had essentially all the available decoding built in to it. It has a built in CD-4 demodulator as well as regular matrix and SQ matrix. So there was no need for the audio enthusiast to have to buy a separate demodulator or decoder. The QX-949 was on the market until 1976 and was part of Pioneer’s new collection of quadraphonic receivers including the QX-949, QX-747, and QX-646. Pricing for the receivers (including walnut cabinets) was as follows:

• QX-949 – $749.95
• QX-747 – $649.95
• QX-646 – $499.95

One audio magazine described the QX-949’s aesthetics:

Its long, elegant, three-dimensional gold and black front panel has enough controls on it to delight the most demanding knob -twirler and yet, when viewed overall, is executed without imposing a cluttered feel. The upper portion of the panel projects forward slightly, its blacked-out dial area illuminated in blue when power is applied.

The QX-949 puts out a pretty decent 40 watts per channel into 4 channels and 60 watts into 2 channels (at 8 ohms).

A distinguishing feature of the QX-949 is the 4-channel level indicator. It basically is an illuminated meter that shows adjustments that are made when listening to a 4 channel source. It shows both front speakers and both rear speakers.  Pioneer even added a 4 CH-MPX out terminal in anticipation of 4 channel FM broadcasting occurring in the future.

Here’s what Pioneer had to say about the 4-channel level indicator:

All four-channel output levels are simultaneously displayed for easy one-glance comparison. A push button attenuator system adjusts indicator sensitivity. This indicator is convenient for the proper adjustment of CD-4 separation while employing the furnished test record.

Audio magazine explained it better in 1974:

At the left is a most unique visual display that looks like an oscilloscope tube but is, in fact, a four light -beam display for direct viewing of each of the four audio channel levels. Green light beams radiate at 45-degree angles from the center outward, increasing their length with increased audio level. Surrounding this display are four small level controls which serve to balance or equalize levels of all four channels. Sensitivity of the display is adjustable over a 30 dB range, using a pair of pushbuttons (-10 dB and -20 dB) located nearby, so that the visual pattern is useful for channel balancing at almost all listening levels.

The tuner section featured a 4-gang variable capacitor and phase linear ceramic filters that gave it great sensitivity and selectivity. Other features of the tuning section are:

• FM front end with MOS FET
• Local oscillator with buffer circuit (QX-949 A)
• Excellent phase linearity and high selectivity.
• High performance multiplex integrated circuit.
• Effective FM muting switch.
• Linear FM dial scale and tuning meter.
• Outstanding AM section

If you need parts for your Pioneer QX-949 there is usually a good assortment of knobs, circuit boards, switches and other items on eBay. You can check what is currently available HERE. There are also lamp kits as well as rebuild and restoration kits available HERE.

QX-949 Features –

Built-in CD-4 Demodulator

Superb frequency response and separation are provided by the phase lock loop circuit with FET. Extremely stable operation is assured even with well used records. Furnished test record is supplied for adjusting carrier level and separation.

RM & SQ Decoders

Built in high performance decoders for Regular Matrix (RM) and SQ matrix deliver top performance in either program source format.

Power Select Feature

Less output power per channel is required for comfortable 4-channel listening than for 2-channel operation. The power select feature allows the user to choose between 4 channels at 53W each or 2 channels at 75W each (with less than 0.3% harmonic distortion at 8 ohms).

Power Amplifier

Four 10,000uF large capacity electrolytic capacitors are employed in the low internal resistance power supply to yield an exceptionally wide power bandwidth. All stages of the high output, low distortion amplifier utilize direct coupled complementary OCL (output capacitor-less) circuit.
Output throughout the range from 20Hz to 20kHz is 40W x 4 {with less than 0.3% harmonic distortion at 8 ohms).

Tone Control Amplifier

Individual tone controls are provided for both front and rear channels. The transistorized negative feedback design results in excellent signal-to-noise ratio with contour-less
variation characteristics.

MOS FET & 4-ganged Tuning Capacitor Front End

Dual gate MOS field effect transistors are employed in the FM high frequency amplifier and mixing stages. Sensitivity, Signal-to-Noise ratio and intermodulation distortion factors are vastly improved. Coupled with the full-coverage 4 ganged tuning capacitor, this highly advanced design provides superb handling of spurious response, imaging, cross modulation and other FM parameters. Stable reception is assured even in high field strength locations by the buffer equipped tuning oscillator.

High Performance – High Reliability IC

Three 2-element phase linear ceramic filters, three stage differential amplifier, diode limiter, and quadrature detector circuits are contained in the IF section. Superior performance design provides low noise, low distortion FM enjoyment. Wide-band stable separation is obtained by the IC stereo decoding circuit.

Comfortable FM Enjoyment

Unpleasant inter-station noise during FM station selection is eliminated by the FM muting circuit which operates from the IF amplifier and FM detector voltage. Truly comfortable operation is obtained. An FM multiplex noise filter is also contained for reducing noise during stereo broadcasts.

IC & Ceramic Filter AM Tuner

The AM tuner employs a 3-ganged tuning capacitor and alignment type high frequency amplifier. Imaging and IF interference are greatly reduced. Superb selectivity and frequency response are provided by the IC and ceramic filter IF amplifier, while interference and distortion are
minimized by the balanced mixer circuit. The frequency converter also employs a balanced mixer for refreshing AM sound quality even in strong field locations.

Recorded Tape Duplication

Since connecting terminals for 2-channel and 4-channel tape decks are provided, together with a tape monitor switch, persons owning two 4-channel tape decks can duplicate four-channel recorded tape. Persons owning a 2-channel and a 4-channel tape deck can record and edit by desired mode (CD-4, RM Matrix or SQ Matrix).

Performance

The QX-949 is an integrated 4-channel stereo receiver which can operate with both conventional 2-channel and 4-channel program source. Functions in the 2-channel mode are: 2-channel stereo record playing, FM stereo reception, AM reception, Tape deck record and playback, and auxiliary source.

The 4-channel Functions of the QX-949 are:

1. 4-channel Discrete Reproduction

Four-channel record reproduction with CD4 phono cartridge equipped turntable; four-channel tape reproduction from 4-channel tape deck.

2. 4-channel Matrix Reproduction

Regular Matrix (RM) and SQ matrix record reproduction, FM matrix 4-channel broadcast reception.

3. Matrix Reproduction of 2-channel Program Source

RM or SQ matrix reproduction can be performed with 2-channel program sources such as stereo records, tape, and FM stereo.

Specifications:

• Power output: 60wpc (stereo), 40wpc into 8Ω (quadraphonic)
• Frequency response: 7Hz to 25kHz
• Total harmonic distortion: 0.3%
• Damping factor: 35
• Input sensitivity: 2.5mV (MM), 150mV (line)
• Signal to noise ratio: 70dB (MM), 90dB (line)
• Output: 150mV (line)
• Speaker load impedance: 4Ω to 16Ω
• Dimensions: 550 x 160 x 440mm
• Weight: 22.4kg
• Year: 1974

The back panel has a plethora of connections including:

• 2 Phono inputs
• Aux
• Connections for 2 Tape Recorders
• Connections for 2 sets of quad speakers (2 front and 2 back speakers in each set)
• AM and FM antenna connections
• 3 AC outlets (1 switched and 2 un-switched)
• A 2 channel power boosting switch
• Dolby adaptor connections
• FM De-emphasis switch
• An AM ferrite antenna

Overall, the Pioneer QX-949 is quite a quad receiver and it is very popular among quad collectors today. To sum up it’s allure Hi-Fi Stereo Review wrote this about the QX-949 in 1974:

It is difficult to do justice to such a versatile receiver in the limited space available. A study of its schematic diagram leaves us with a sense of amazement that such a complex instrument can be sold for only $750. It is not only a handsomely styled and highly flexible four-channel control center, but, in respect to the electrical performance of its tuner and amplifier, it rivals some of the finest separate -component systems.

High Fidelity wrote this:

All told, the QX-949 strikes us as typical of Pioneer’s relatively uncompromising approach to receiver design. It combines four channels of clean and fairly powerful amplification and an above -average tuner with a CD -4 demodulator and matrix decoders for both SQ and RM, plus more than minimal switching for tape decks and other ancillary gear. That really is a lot to cram into a receiver, even at $750.