Pioneer Vintage SPEC-4 Hi-Fi Power Amp Amplifier SPEC 4
One of Pioneer's All Time Best Amps! Classic Power! NR!!
Pioneer SPEC-4 Power Amplifier
Original Owner’s Manual
Original Brochure
Original Full-Size Schematic
All Other Equipment Shown in Rack & Video Not Included in This Auction, Although Available in Other Auctions
Pioneer : a person or group that originates or helps open up a new line of thought or activity or a new method or technical development.
The originators of Pioneer Electronics Corporation chose this name carefully, it was the one word that best described their ambitions. It was much more than a name it was a motto that they would strive to fulfill in every product they produced. Today, over 65 years later, Pioneer is recognized as a leader in technology advancements in the consumer electronics industry because of their undying determination to live up to this name. They have numerous “World’s Firsts” credited to them and they have greatly influenced and excelled the path of audio componentry. Over the last 65 years they have created countless imaginative and first-rate products which have irrefutably won the hearts, and ears, of the world’s elite audiophiles.
Pioneer’s SPEC line was a series of elite individual components geared towards the discriminating audiophile. Each component in the SPEC line was efficiently overbuilt rivaling far more expensive components on the market.
The SPEC-4 was introduced in 1977 with a production run until 1981. It was the successor of the SPEC-2 amplifier, and while it had a lower rated power output, it also had a lower overall distortion level and a more refined sound. No one was complaining, its 150 watts per channel RMS with a mere 0.01% distortion level was more than satisfying for even the most demanding and revealing speaker system.
The SPEC-4 is a true power house built at the peak of Pioneer’s marketplace dominance. It provides amazing power with all the sonic details and accuracies you would expect from their flagship component line. It is the perfect representation of the “Pioneer silver era” sound. Other features and functions include:
Stereo Power Amplifier in “DC Configuration with Independent Left/;Right Dual Power Supplies & Circuitry
-Think of the Pioneer Spec-4 amplifier as two independent mono amps in one chassis. Pioneer’s stay-ahead reputation in hi-fi technology was upped another big step here by achieving real independence for the essential circuits in both the left and right channels. Physically separated signal paths and dual power transformers, four big capacitors (two per channel) to prevent power dry-up, separate left-right relays everything to prevent crosstalk and distortion that erode stereo clarity and tonal quality. Because the SPEC-4 is of Pioneer's premier generation “DC" configuration power amps, its performance is never compromised by capacitors in the negative feedback loop. The results: a continuous power output of 150 watts per channel, min. at 8 ohms from 20 to 20,000Hz with no more than 0.01% total harmonic distortion.
Dynamic Power with Ultra-Low Distortion
Why go for a separate component for power amplification? Pioneer's SPEC-4 clears up that question, and your music, with indisputable proof that separate power amplification is really worth it. It delivers a continuous power output of 150 watts* per channel, min. at 8 ohms from 20 to 20,000Hz with no more than 0.01 O/O total harmonic distortion. Massive power reserve is available throughout the spectrum, including the super-low and ultra-high ends. Pulsive' signals -i.e. musical signals -are reproduced with transparency and clarity at all levels, at all times. This high quality is achieved with Pioneer's stay-ahead technology, as explained below.
Stay-Ahead Audio Circuitry
The Pioneer SPEC-4 uses innovative circuitry for power amplification, as follows: The input is formed by a dual- PNP transistor differential amplifier, loaded by a current mirror circuit. This is followed by a constant-current-loaded pre-driver and a 3-stage Darlington connected driver. The final output is in the parallel SEPP (Single Ended Push Pull) configuration. Here are the advantages, one by one: (1) Dual-PNP Differential -Zero DC voltage is constantly maintained at the input. (2 Current-Mirror Loading -Reduces the load to the differential input to achieve a high gain which, in turn, permits the application of sufficient negative feedback for the effective reduction of distortion. DC stability is also improved. (3) 3-Stage Driver -Again loads are reduced so that the transistors in the circuit are called on to operate only at their most linear operating curve. Distortion is reduced and gain is high. (4) Parallel SEPP -This output configuration reduces by half the amount of current flowing through the output (power) transistors, again allowing the utilization of only the most linear parts of their operational curves, reducing distortion without sacrificing output
Dual Power Supplies For Left & Right Channels
Better 2-channel performance all around. That's the result of physically separating the left-channel and right channel power supplies and signal paths. Paired power transformers are employed, one for each channel. The advantages show up in steady-state as well as dynamic conditions. We've even separated the power relays for the two channels. No matter how complex the signal handled by one channel,the other is always ready to perform independently for more musical clarity. Think of the SPEC-4 as two independent mono amplifiers housed in one stereo unit
Massive Power Reserves
Power dry-up? It takes an acute ear to detect it from most amps when they are playing ordinary music. But it shows up easily during dynamic stereo passages in rock, classics and other music unless definite measures are taken to prevent it. The Pioneer SPEC-4 takes those measures. Because it operates on a "DC" basis, with no capacitors whatsoever in the negative feedback loop, and because it features a truly dependable power supply formed of two huge power transformers and four 22,000uF filter capacitors, power dry-up is entirely avoided. Your music is reproduced with vivid, full-power lows and natural transients for high resolution.
Low Impedance Design Throughout
Impedance plays a very important role in amplifier design and behavior. High impedance in the grounding and hot lines can result in significant losses of power and increases in distortion. The SPEC-4 avoids this in the following ways: (1) Pure Copper Grounding -Low impedance prevents the generation of distortion and safeguards power loss. Pioneer achieved it with the use of pure copper plates, 20mm wide by 2mm thick, in the ground path of the dielectric capacitors. (2) 14-Gauge Cables -Again, low-impedance performance is assured with the use of very thick (2.03mm or 14 gauge) stranded cables in connecting the power output assembly to the output terminals and throughout significant large current circuits. Reproduction never suffers, yen when large current flows are suddenly introduced. These "coat-hanger" cables also permit the dielectric capacitors to charge quickly and efficiently. (3) Copper-Foil Circuit Boards- Conventional printed circuit boards use thin layers of copper foil. Ours use layers twice as thick-70p- to further reduce circuit impedance even when large current flows are required.
Peak Reading Power Meters
The logarithmically compressed scales of the twin power-output meters on the front panel of the Pioneer SPEC-4 makes it easy to read peak power output in both channels accurately. No sensitivity changing is necessary when large or small output levels are chosen. The large, outer-magnet type meters indicate the full output peaks within 70 milliseconds aided by an advanced detection circuit for instant-by-instant accuracy. Their direct-readout scales indicate from 0.01 watt to 300 watts
Independent Level Controls
Also on the front panel are independent level controls for each channel's input. Optimum input level sensitivity is thus easy to achieve regardless of the output of the connected preamplifier. Each control is an attenuator with 22 stops, calibrated precisely in 1dB increments from 0 to -20dB. Gang error and indication error are minimum so that you may adjust inputs delicately and accurately
Power Protection Title Here
The SPEC-4 circuit for speaker and power transistor protection is formed of a quick-response power relay and a dependable electronic detection stage. Detection of DC components and overload currents is instant, triggering the relay and electrically disconnecting the amplifier from your speakers and its own output stage. The protection circuit also serves as a muting circuit which eliminates click noise otherwise heard when you switch the power on or off. Pioneer has taken extra steps to protect stereo separation with the use of two independent relays, one for each channel, with twin contacts in parallel. Surge current, in- troduced as you switch the power on, never reaches the large power transformer/capacitor block thanks to this extra protection.
Rear Panel Terminal Protection
rear terminals are protected from damage with a terminal protector.
Stylishly Professional Front Panel Design
Just as you would expect from a sophisticated system, the SPEC-4’s front panel is professionally designed with the large level meters in the center. Also, the front panel’s dimensions allow the model to be mounted in an EIA standard rack, just like real professional-use amplifiers.
Switchable Voltage Selector
Unit has adjustable voltage (110/120/220/240V 50/60Hz) to match any country’s requirements
And Much More!
Actual SPEC-4 is featured in this video Other equipment not included, but available in my other auction. ****Please view in full 1080p by checking appropriate resolution in settings box****
Continuous power output of 150 watts per channel min, at 8 ohms from 20 Hertz to 20,000 Hertz with no more than 0.01% total harmonic distortion of 180 watts per channel at 4 ohms from 20 Hertz to 20,000 Hertz with no more than 0.03% total harmonic distortion.
Total Harmonic Distortion (20 to 20,000 hertz;,8 ohms)
No more than 0.01% (continuous rated power output) No more than 0.01 % (75 watts per channel power output) No more than 0.01 % (1 watt per channel power output)
No more than 0.01 % (continuous rated power output) No more than 0.005% (75 watts per channel power output) No more than 0.005% (1 watt per channel power output)
Frequency Response:
5 to 100,000Hz +0dB, -1dB
Input Sensitivity/Impedance
1V/50 Kohms
Output Speaker
4 to 16 ohms
Damping Factor
100 (20 to 20,000Hz, 8 ohms)
Hum and Noise
115dB (IHF, short-circuited A network)
Semiconductors
ICs: 2 Transistors: 61 Diodes: 62
Power Requirements
110/120/220/240 Volt 50/60Hz (switchable)
Power Consumption
760 watts/950 VA
Dimensions
19” W x 17 ¾” D x 7” H
Weight
54 lbs unpacked
Amplifier was extremely well cared for and is in excellent condition. It does not have the usual dust and grime build-up, it is very clean. Unit was gone through by a tech and inspected, all switched and controls were properly cleaned. Unit was fully tested and is operating phenomenally. It plays amazingly well on both channels with no hum or distortion. All features and functions are working, including lights and meters. Looking it over closely there are a couple of very tiny “flea bites” on the face, only noticeable when looking for them.
This is a No Reserve Auction so it will go to the highest bidder.
I specialize in shipping large delicate items and I know what it will take to pack this right. All you have to pay towards shipping, insurance, packaging material, and expert packing is $44.75 to anywhere in the continental U.S. I will also ship this unit World Wide and will only charge the Actual Shipping cost.
Please note: the item pictured is guaranteed to be the actual item you will receive. None of my pictures are taken off other peoples pages or web sites, so bid with confidence - what you see is what you get!
PayPal and any other eBay approved payments gladly accepted! (please email for details) Never a handling fee, buyer pays actual shipping as stated above.
International bidders welcome.
Click here to check out my other auctions for more great items!
