Descrizione

Dal sito: http://www.incomesixdigits.com/spec4/

Dynamic 150 + 150 Watts Power Output, Generous High-power Design

The Spec-4 employs DC construction which excludes capacitors from the NFB circuits and uses a dual transistor differential amplifier with a current mirror circuit in the 1^st stage. This provides a stable operation and also high gain over a wide frequency range. The pre-driver stage is a class A amplifier circuit with a regulated current circuit for the load. This makes for high-gain amplification with superior linearity. Furthermore, there is an overdrive limiter and power limiter circuit which is designed to protect the power transistors and make for added reliability.

The power stage employs a 3-stage Darlington pure complementary parallel SEPP circuit.

The SPEC-4 delivers Continuous Power Output of 150 watts per channel, min. RMS, at 8 ohms from 20 Hertz to 20,000 Hertz with no more than 0.01% total harmonic distortion.

Completely Independent and Perfectly Stable Left / Right Power Supplies

The mighty power supplies are completely separated for the left and right channels. Also, each channel is provided with two 22,000uF large-capacity electrolytic capacitors and large transistors with a superior regulation. They achieve outstanding channel separation and a clear, powerful reproduced sound, in addition to the wide frequency response. There is a built-in surge killer circuit to suppress inrush currents from the power transformers and high currents which charge the electrolytic capacitors. This circuit ensures that none of the parts are affected by these adverse currents.

Protective Circuits Composed of Fast-response Relays and Electronic Circuits

Each channel is protected by a DC and overcurrent detection relay circuit. In the event of the speaker terminal shorting due to poor connections or when DC current is generated in the output, the output circuit is immediately disengaged and the speakers and transistors are safeguarded against any possible damage. The protective circuits also function as muting circuits when the power switch is turned on and off.

Peak Level Meters with Outstanding Waveform Response

This power amplifier incorporates logarithmic compression peak meters with a wide scale (-40 -+3dB). With 8-ohm speakers, they allow the output to be read out from 0.01W to 300W. Moreover, the meters feature a fast response for peak signal indication. In addition to the peak output reading, it is easy to interpret the dynamic margin with respect to the SPEC-4’s clipping level.

Input Level Controls with dB Calibration

The SPEC-4 is equipped with input level controls with direct readout attenuation values (-dB). These can be used to continuously adjust the input levels for each channel in accordance with the rated output voltage of the preamplifier. In this way, the SPEC-4 can perform the proper gain control according to the preamplifier’s output level. The preamplifier will thus be used in the condition possible for the best S-N ratio and distortion characteristics.

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.

SPECIFICATIONS

ICs………………………………........................................2

Transistors………………………………...........................61

Diodes……………………………….................................62

Power Amplifier

Circuitry………………………………Current mirror loaded differential Amplifier

3 stage darlington parallel push-pull

Direct-coupled OCL. (DC amplifier construction)

Continuous Power Output of 150 watts * per channel, min. RMS, at 8 ohms from 20 Hertz to 20,000 Hertz with no more than 0.01% total harmonic distortion, or 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 Hertz to 20,000 Hertz, 8 ohms)

Continuous rated power output………………………………................................0.01%

75 watts per channel power output……………………………….......................... 0.01%

1 watt per channel power output……………………………….............................0.01%

Intermodulation Distortion (50 Hertz to 7,000 Hertz = 4:1, 8 ohms)

Continuous rated power output………………………………................................0.01%

75 watts per channel power output……………………………….........................0.005%

1 watt per channel power output………………………………........................... 0.005%

Frequency Response………………………………...............5 Hertz to 100 kHertz +0/1 dB

Input (Sensitivity / impedance)……………………………............................1V/50k ohms

Output

Speaker……………………………….................................................4 ohms to 16 ohms

Damping Factor (20 Hertz to 20,000 Hertz, 8 ohms……………………………….........100

Hum and Noise (IHF, short circuited, A network………………………………........11 5dB

Miscellaneous

Power Requirements………………………………...................................AC 120V 60 Hertz

Power Consumption………………………………..........................................760 watts (UL)

Dimensions………………………………..............................480(W) x 187(H) x 445 (D)mm

18-7/8 x 7-3/8 x 17-7/16 in.

Specifiche

Tipologia amplificazione	transistor
Potenza RMS per canale	150 W
Carico di riferimento	8 ohm
Distorsione armonica (THD)	0.01 %
Risposta in frequenza	5 Hz to 100 kHz
Sensibilità ingresso linea	1V
Impedenza ingresso	50 kOhm
Rapporto S/N	115 dB
Consumo elettrico	760 W
Alimentazione	AC 120V 60 Hz
Dimensioni	L 48 × A 18,7 × P 44,5 cm
Produttore	Pioneer

Sul marchio

Pioneer nasce a Tokyo nel gennaio 1938, quando Nozomu Matsumoto apre un laboratorio di riparazione di radio e altoparlanti; l'anno prima aveva sviluppato l'altoparlante dinamico A-8. L'azienda ha preso il nome Pioneer Electronic Corporation nel 1961 e negli anni Settanta e Ottanta è stata uno dei grandi nomi giapponesi dell'hi-fi, con un catalogo che andava dai giradischi ai registratori, dagli amplificatori ai sintoamplificatori e ai diffusori.
Tra i modelli più ricordati c'è il giradischi PL-12D, presentato nel 1973 e per circa tre anni in testa alle vendite nel Regno Unito; il registratore a bobine RT-1020L, dello stesso anno; il finale in classe A Exclusive M4, del 1974, della linea di prestigio Exclusive; il ricevitore SX-1980 del 1978, della serie SX. Pioneer è stata protagonista anche del video domestico con il LaserDisc, il cui primo lettore per la casa uscì nel 1980, e più tardi con i televisori al plasma Kuro.
Il marchio esiste ancora, ma la sua storia recente è complessa. Nel 2014 Pioneer ha venduto al fondo KKR il settore delle apparecchiature per DJ, che oggi è un'azienda a sé, e ha concordato la cessione della divisione audio-video domestico a Onkyo, completata nel 2015. Dal 2021 gli apparecchi hi-fi a marchio Pioneer sono prodotti su licenza da una società comune di Premium Audio Company e Sharp, mentre Pioneer Corporation si dedica soprattutto all'elettronica per l'auto. Sul nostro sito si trovano solo esemplari usati e vintage.
Da Audiocostruzioni passano apparecchi Pioneer usati e vintage: quelli disponibili sono in questa pagina e si possono vedere e ascoltare nello showroom di Carpi oppure ordinare online con spedizione. Per qualsiasi domanda potete scriverci via email.

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