I was also able to gather the following information from the net:

Transformer Details

Manufacturer: Ten Pao International Ltd.

Model No: TOG433028F0

Input: AC 230V/50Hz

Output: AC 20.1V x 2

Diameter: 95 mm;

Height: 45 mm.

Amperage: Unknown

VA: Unknown

I opened my Z-2300 subwoofer and clicked some pictures, which i am posting below:

Based on the size - I would guess that this one is about 120VA.

But I don't know since Z-2300 is capable to deliver 200W RMS & 400W RMS peak power.

Z-2300 Specifications

Total Continuous Power(RMS): 200W

Total Peak Power(RMS): 400W

Also Z-2300 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.

So, do you think since it powers 4 TDA chips, it is 300VA rather than 120VA considering its size?