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star A.C. Devices
star A.C. EMI Filter
star A.C. Spectrum Verion 2
star A.C. Spectrum
star Digital Oscilloscope
star Flat Top A.C.
star Isolation Transformer - Safer Power Supply ?
star Isolation Transformer
star MCB - For Testing
star Relay - Power Failure Manual Reconnection System
star Soft Start Circuit
star Soft Start Circuit 2
star Tube Amplifier
5Z3P, 6N9P, EL34

Useful Info.

star AWG Vs mm

My AV System

star System Info.
star Testing Result 2016-5-14
star Testing Result 2014-7-27

Case Opening

star Cambridge Audio
CA 351C
star KEF Q300 Speaker


star 5z3p 6n9p EL34
Tube Amplifier DIY kit
star AudioQuest USB A-B Forest 1.5m
star B&W 685 S2 speaker
star WireWorld RCA Luna 7 1m

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Case Opening

KEF Q300


KEF Q300 Speaker Disassembly
KEF Q300 Speaker

KEF Q300 2-way Hi-Fi Speaker

Manufactured in China

I sticked a hook on the rim, then I pull out the plastic rim.

KEF Q300 Uni-Q unit

You can see some mold on the rim.

This may be due to the high humidity in Hong Kong. Inside my flat, the humidity is always higher than 80%.

The plastic rims that pulled out at the beginning.
KEF Q300 rusted screw The screw is rusted ... ... the Quality Control is ... ... failed
KEF Q300 Speaker Socket If you would like to upgrade the inner wiring or the Speaker Crossover, you have to uninstall the speaker and this plate.
KEF Q300 crossover

Go ahead ... ... uninstall the speaker socket ... ...

The crossover is installed at the back ... ... why ???

KEF Q300 Sound-absorbing cotton Lots of Sound-absorbing cotton

KEF Q300 Uni-Q unit

At the center, woofer connections

On both sides, tweeter connections

KEF Q300 Speaker Cabinet Inside the speaker cabinet

The manufacturing standard is Pass or Fail ?

I have no idea because this is my first disassembly of a Hi-Fi grade speaker.

KEF Q300 Crossover
Now, you should know the reason of installing the crossover at the back of the speaker sockets.

KEF Q300 Speaker Socket

When you turn the two knobs among the sockets, the metal plates will make contact with the circuit board (Red , Yellow arrows), then you do not have to use the jumpers shown in the photo.