Need help with transistor selection

[donpetru]

Hi, I need some advice on what transistors you guys would advise for the input stage of an amp running +-45V DC rails.

Also need giudance on a good selection for the smaller transistor to pair with the C3503 VAS transistor.

Im kinda limited to RS components, and dont want to order 100s of transistors.

Any help would be great.

Was using 2n5551 and 2n5401, dont have any left.

You better post amplifier schematic because the bias current in the VAS stage dictates the type of transistors used. So, a general answer to these questions does not really exist, because each audio amplifier topology has its "little secrets". It is possible that in a certain part of the schematic the pair 2N5401 / 2N5551 will work better, but in other situations may be MJE340-350...

LATER EDIT: Now I saw schematic. The KSA1381 / KSC 3503 pair you chose is ok. However, check the heating of these transistors.

 

[Vostro]

Hi donpetru thanks for your reply. The C3503 are on adequately sized heatsinks. The problem is I'm out of stock on the smaller TO92 transistors. And I'm struggling with the BC550/BC560. Using BC337 in the current mirror as a substitute for now. But am looking for 2n5401/2n5551 or adequate substitutes.
So looking at alternatives and availability in my country.

Regards