This listing includes four pieces of IRFP9240 power MOSFET for audio amplifier output stage application.
The four parts are tightly matched for diy audiophile projects.
For tightly matched we are referring to the below criterion :
1. The four pieces have to be from the same batch ;
2. The four pieces have Vgs matched to 30mV variation with the same drain current.
In order to ensure the MOSFETs to be identical when working in deep class A mode, the matching was done at a high Drain current of 1Amp !
Normally only two out of ten can be such matched. To give a good quad matched 20 random pieces are usually needed.