The main amplifiers are capable of putting out much higher currents and voltages than the smaller op-amps. .........

............to the speaker outputs (which are driven using the class AB power op-amps).

Thanks jackand08, for showing me the light. Now i do know what that 4565 does.

I made a list of my finding inside the Z-2300 as below:

The amplifier uses:

i) Two STMicroelectronics Class-AB, 80W, TDA7295 amplifiers bridged together to provide a total of 2 X 80=160W for the subwoofer.

**[Assumed]**
ii) Two STMicroelectronics Class-AB, 60W, TDA7296 amplifiers powering each of the satellites.

iii) A Japan Radio Corporation’s JRC-4565 operational amplifier required for the headphones in the control pod.

iv) Filtering of the audio signal is done by two beefy SamXon/ CapXon 10,000 uF, 35V capacitors.

v) The amplifier board have two voltage regulators/ stabilizers a 78M18 and a 79M18, making positive and negative 18 volts respectively.

Total amplifier power of Z-2300 = 2 X 80 + 2 X 60 = 160 + 120 = 280W

**Why does Logitech quotes Z-2300 have 200W when the total power reserve is 280W?**
Also the toroidal transformer details are as below:

Manufacturer: Ten Pao International Ltd.

Model No: TOG433028F0

Input: AC 230V/50Hz

Output: AC 20.1V x 2

Diameter: 9.5 cm;

Height: 4.5 cm.

Amperage: Unknown

VA Rating: Unknown

Judging by the size of the toroid some are telling it is 120VA.

**My question is can a 120VA toroid provide 200W power Logitech claims for Z-2300?**
Specifications of Z-2300 are provided below:

Audio Quality Certification: THX certified

Total Continuous Power(RMS): 200W

System THD: Better than 0.05% before clipping

Total Peak Power(RMS): 400W

Power distribution: 120 W (Subwoofer) + 2 X 40 W (Satellites)

Subwoofer: 120 W @ 8 ohms

Subwoofer Size (inch): 8

Satellites: 80 W (2 X 40 W) @ 8 ohms

Satellite Size (inch): 2.5

Frequency response: 35 Hz - 20 kHz

Signal to noise ratio(SNR): @ 1kHz > 100dB

Sound Pressure Level (SPL): 117db

Subwoofer dimensions(HWD): 11" X 11" X 15"

Satellite dimensions(HWD): 6.75" X 3.5" X 6"

Total weight : 15 Kg