P-7300 is full model change of P-7100 which launched in2006 and our flagship class-AB stereo power amplifier.
Technical high lights of P-7300 are ULTRA LOW NOISE
and SUPER HIGH DAMPING-FACTOR.
They are inherited from our flagship class-A monophonicpower-amplifier A-200.

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P-7300 shrinks in chassis size, depth 30mm and height
20 mm to provide the good usability.
Unit’s weight is almost same as the former model P-7100.

2P-7300 has analog power meters with peak-hold andhold time control functions.
2 pairs per channel of large speaker terminals areequipped. They are useful for a bi-wiring connection withloud speakers.

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Strong power supply by large Troidal transformer withaluminum heat-radiation fins and 2 pieces of 56,000μF
special capacitors are installed.
They are specially developed for hybrid electric vehicles,
and have a specialized structure for vibration-proof
characteristic.
Power transformer: 14.6 kg

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P-7300 is a high-power Class AB amplifier which delivers
rated output power 125W/8Ω, 800W/1Ω.
To observe severe safety regulation of exteriors
temperature rises with the shrunk body, rated output
power at 1 ohm load has been suppressed from P-7100.
Rated output power
Load

8Ω

4Ω

2Ω

1Ω

P-7300

125 W

250 W

500 W

800 W

P-7100

125 W

250 W

500 W

1000 W

But, thanks to a strong power transformer, maximum
output power at 8 Ω and 4 Ω load has been enhanced.
Maximum output power
Load

8Ω

4Ω

2Ω

1Ω

P-7300

220 W

383 W

620 W

899 W

P-7100

173 W

334 W

620 W

1045 W5

P-7300 achieves 12μV of actual output noise voltage.
This is less than half of the former model P-7100.
P-7300 is the lowest-noise stereo power amplifier in theexisting Accuphase product line-ups.

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The output noise is reduced by some technologies.
Optimizing gain allocation of 2 amplifier blocks
constructed with the instrumentation amplifier.
Enhancing the gain of balanced input amplifier blockfrom 4 times to 12.6 times.
Output noise voltage is ideally decreased to 33%.

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The output noise is also reduced by the discreteconfiguration amplifiers which no ICs are on signal path.

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P-7300 achieves 1000 of Damping-Factor. This is over
3.3 times higher than the former model P-7100.
This is guaranteed specification. In actuality P-7300 has
more than 2000 of Damping-Factor.
*Damping-Factor:
A index of speaker driving ability. Higher Damping-Factor
amplifier has higher speaker driving ability.
DF = 8 ohm / Output-impedance

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The Output impedance is decreased by 10 parallel pushpull output stage arrangements of bi-polar transistor.

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Remote-sensing is the technique to lower output
impedance of amplifier by the negative feedback withsignal sensing from close up the speaker terminals.
Balanced Remote-sensing is the technique to make
impedance even lower by GND sensing and the negative
feedback of GND level with adding the signal sensing.
Not only Damping-factor is improved but also Total
Harmonic Distortion and Intermodulation Distortion getbetter by Balanced Remote-sensing.

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Mechanical relay is the most common for speakerprotection. It does not have good reliability and so lower
contact resistance either.
P-7300 employed MOS-FET switch instead of
mechanical relay for speaker protection.
Damping-Factor, reliability and sound quality are
improved thanks to MOS-FET switch.
Also, large speaker terminals, rectangular wire coils andsome other very low resistance-components are
specially selected for P-7300.
Making signal path thick and short attains a lowimpedance.

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