IF THIS IS FOR YOUR MAIN AMP SECTION. SWITCH TO MJ21193G AND MJ22294G. THESE ARE VERY LINEAR AND CAN HANDLE THE POWER. PLEASE CHECK THEM OUT. A LOT OF PEOPLE USE THEM INCLUDING MYSELF ON A STA 2100. MOST GOOD TECHS SHOULD AGREE.
https://www.mouser.com/datasheet/2/308/MJ21193-D-108487.pdf ALWAYS CHECK AGAINST YOUR STATS.
Step by step instructions:
- Choose a transistor of the same polarity: The first major selection criterion is whether the transistor is PNP or NPN.
- Select a replacement transistor of the same material: Most transistors are either silicon or germanium. As bias voltages and other features are different it is necessary to select a replacement transistor with the same material.
- Select the same functional type of transistor: Transistors are normally given an indication of their application in the datasheets. The replacement should have the same application if possible.
- Choose a replacement with the same package: Choosing a replacement transistor with the same package and pin-out will mean that many of the characteristics including power capability are the same. Ensuring with pin-out is the same (most but not all transistors have their leads in order - EBC) will save many problems with fitting.
- Select a replacement transistor with the same breakdown voltage: Ensure that figures for VCEO and VCBO etc are at least as high as the original transistor. Voltage at least or higher
- Check it can take the current: Ensure that the replacement transistor can pass the required current - it should have an ICmax greater than or equal to the original transistor.
- Collector Current is Greater than or equal to
- Select a transistor with a similar Hfe: It is necessary to ensure that the current gain of the replacement transistor is about the same as the original. Current gain values normally vary widely even for transistors of the same type so some variation will be acceptable.
- Similar dc current gain
- Select a replacement transistor with equivalent Ft: It is necessary to ensure that the replacement transistor will be able to operate at the relevant frequencies, so a similar or slightly higher Ft is advisable. Don't go for a transistor with a much higher Ft as this may increase the risk of oscillation.
- . Don't go for a transistor with a much higher transition frequency, NOT ALWAYS A NECESSARY FACTOR.
- Choose a transistor with a similar power dissipation : It is necessary to ensure that the replacement transistor can handle the power that it will dissipate within the circuit. Choosing a replacement transistor with a similar can style will often mean that both transistors have a similar power dissipation.
- similar power dissipation in collector can be more
- Check for any special features: While ensuring the features above are selected, there may be some additional features that need to be considered. These are normally required when transistors are used in specialist applications.