can I replace ztx450 to bc 550 in ZenV4

[elviukai]

I searched everywhere, no letf in whole country

I tryed bc 639, but R0 blown and fets too.. ( I put legs right, no mistake- have change legs because ztx 450 and bc 639 has diferent)

any help? what n chanel transistor I should use? I was thinking that any npn device but now I see its wrong.

24 mosfet are already dead, as a 12 RO (o,47om)

[dieringe]

you can use any ordinary NPN, i used bc 546, 548, 550 and
ztx 653 (more power than 450). your problem shouldn't be this transistor.

[till]

My Zen V4 runs with BC550 without problem.

You have another problem.

Try to run the amp with less bias first / make R0 not to small first. Try 1A or so.

Double check all pins and connections of Transistors and FETs.

Make good connection short wires to power supply.

If does not work: Test the regulator alone first, the test the amp with the aleph current source modulation resistor disconnected.

[elviukai]

very srange.. because I have only one ztx 450. and both chanels work great wih this one, I do only one thing- resolder ztx 450 and solder in its place bc 693. rezult was obviuos - r0 down ..

[dieringe]

strange, yes. as you connected it correctly, maybe your bc639 is bad?