F-4/BA-3 Transistor Kit
Included in this kit are the semiconductors needed to complete an F-4 amplifier or BA-3 output stage, with the exception of the input JFETs. MOSFETs were matched in accordance with standard operating conditions. This is enough transistors for 2 channels (one stereo amplifier).
The IRFP9140/IRFP240 MOSFETs were matched at the rail voltage and current that the BA-3 and F4 articles suggest, specifically, 22v and .4A, and then grouped by VGS to within .1V.
- The current batch of kits includes Harris IRFP9140 instead of the International Rectifier version. These have better distortion characteristics and are a sonic upgrade, but it should be noted they are rated for 100V.
- Any numbers on the MOSFETs are ID numbers only, and are not related to their measurements nor their matching