2n3859a in place of q3 in P3a
Hello again, I build a P3a few weeks ago, now I builded the other channel but I had q9 turned around(figured that out after I blew the transistors  ) and I applied +/-25Vdc to the rails and q1, q2, q3 burned up and the output transistors got really hot, since I didn't have the heatsink on because the other channel never got even warm while playing music for a very long period of time. 
Luckly I didn't damage any of the other transistors. I had 2 bc546 transistors that I used for q1 and q2, but I don't have a third one to use for q3, so I searched for transistors at my house I found a few that can be used (while I wait for the order to come which won't be anytime soon), one of them is 2n3859a I found its datasheet online and it is the closest thing I could find to bc546. Here is the datasheet of the 2n3859a:
http://212.57.231.17/datasheets/39/OTNONQUNNR.pdf
and the bc546 datasheet:
http://www.onsemi.com/pub/Collateral/BC546-D.PDF
Yeah, so I put the 2n3859a in as I payed attention to the pinout, I double checked everything and I powered up, the output voltage is around 500mV, the voltage drop accross the q9 base emitter is 0.67 V, as it is suposed to be. But here is the thing that bothers me Q7 gets warm and the voltage drop accross the LED is 5.46V as I am powering the amp with 6V rails for now. I can't recall what the voltage was on other channel right now, since I put it up for now, at least until I get an answer from you guys or I get the real transistors. I connected the speaker and got input from my CD player and I could hear sound coming out, so I am assuming that everything is ok as far as the output transistors are concerned. Is there any modifications that I could do to temporaraly fix the problem? I just can't wait that long, last time they got here 4 weeks after the order and I ordered only 10, since I thought there were 5 in each channel.
Any help would be greatly appreciated, thanks in advance.
~Petar~
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27th February 2004, 01:01 AM
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