Specifications

DIN Continuous power output (both channels driven at 1 kHz)
85W + 85W into 4 Ohms. 1% THD
60W + 60W into 8 Ohms. 1% THD

Continuous power output (both channels driven at 20 Hz to 20kHz)
70W + 70W 4 Ohms, 0.05% THD
50W + 50W 8 Ohms, 0.03% THD

Dynamic power output (on EIA dynamic test signal)
135W/100W/70W into 2 Ohms /4 Ohms /8 Ohms

Total Harmonic Distortion
0.03% at 20Hz-20kHz , 50 W, 8 Ohms
0.05% at 20Hz-20kHz , 70 W, 4 Ohms

Frequency Response
5Hz-100 kHz + 0/- 3 dB (CD, Tuner, Aux, Tape)
20Hz-20 kHz +/- 0.3 dB (Phono MM)
20Hz-20 kHz +/- 0.5 dB (Phono MC)

Signal-to-Noise ratio (IHF short circuit, A network)
108 dB (CD, Tuner, Aux, Tape) 
87 dB / 69 dB (Phono MM, 2.5 mV input, Phono MC, 0.2 mV input)

Signal-to-Noise ratio (DIN, continuous power/50 mW)
88 dB / 65 dB (CD, Tuner, Aux, Tape) 
74 dB / 63 dB (Phono MM)

Input sensitivity/impedance
CD, Tuner, Aux, Tape: 150mV/ 50 kOhms
Phono (MM): 2.5mV/ 50 kOhms
Phono (MC): 0.2mV/ 100 kOhms

Power supply: 240V AC, 50/60 Hz
Power consumption: 520 Watts

Dimensions:420(W)x352(D)x126(H)mm
Weight: 8.0 Kg

Datasheet submitted by Job Chithalan

Pioneer A400 is a no frills 'audiophile' amplifier that set the 'cat among the pigeons' when it was introduced in 1990. Hi-Fi magazines greeted it with a chorus of praise. Comparisons with amplifiers costing up to £1,000 were made, confirming that the A400 is a 'giant killer'. 

25,000 units were sold in the first 18 months, securing an extraordinary 12.8% of the total amplifier market. Soon, the Pioneer A400 attained something of a cult status. A400X model was introduced later but the demand was still for the original A400 and the production continued till 1996.

It won the coveted Product of the Year by the What Hi-Fi? magazine - an accolade that had never before gone to a Japanese company. 

What the press said:

"There is something ineffably right about the Pioneer A400." 
Andrew Gold, What Hi Fi?

"It loves music, the A400." "It loves it with a vengeance." 
Mark Payton, High Fidelity Magazine

"Even if your budget extends to £1000, it could be exactly what you are after"
Jimmy Hughes, Audiophile

"As good as amps costing up to a thousand pounds." Hi Fi Choice

"Best Amplifier", "Best Buy Overall", "Product of the Year" What Hi-fi?

"Best Amplifier" Hi Fi Choice

Useful Links:
http://www.users.globalnet.co.uk/~dougr/a400.htm

Hi-Fi Buying Guide: Part 2
http://www.tnt-audio.com/guide/amps_e.html

Hi-Fi Buying Guide: Part 4 
http://www.tnt-audio.com/guide/building_e.html

User reviews:
http://www.audioreview.com/Amplifiers/Pioneer

A 400X review
http://www.tnt-audio.com/ampli/400e.html

A300 Precision review by Hi-Fi Choice
http://www.hifichoice.co.uk/archive/perl/433_printreview.htm

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