LOL, let's stop the confusion. Here is what I gleaned from the customs website.
There are two taxes an item is subject to - sales tax and import duty. These taxes are calculated on the cost of the item plus shipping and insurance.
"Musical instruments, the sound of which is produced, or must be amplified, electrically (for example, organs, guitars, accordions)."
No sales tax, no import duty.
"Parts and accessories of the musical instruments [above mentioned]."
10% sales tax, no import duty.
"Audio-frequency electric amplifiers."
10% sales tax, 15% import duty. Special rate of 8% (instead of 10+15=25%) applicable if movement is within ASEAN countries.
Tax charges at Malaysia Custom, From Singapore