quad eight opamp transistors vs +-V

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rafafredd

Well-known member
Joined
Jun 3, 2004
Messages
2,409
Location
Rio, Brazil
So, I just built some Q8 AM10 opamps, but I´ve used 2n4401 and 2n4403, with bc301 and bc303 at the output. The problem is that those 2n4401 and 2n4403 parts are only 40v and the opamp is supposed to run at +-28v. OUCH!

I should have checked the 4401 and 4403 ratings before soldering, but I didn´t :evil: :oops:

So, do you think I can run it at +-28v or shopuld I stay safe at +-20v?
 
There is a good chance that "40V" parts will take 50V, maybe 60V.

Since they are already soldered: just try it.

Most of the transistors in a +/-28V opamp will only see 28V at idle, so you need to put large signals through it and swing everything to extremes to stress it.
 
And remember, that maximum voltage rating is collector-emitter voltage. You should only be concerned if the difference between the voltages on the collector and the emitter approaches 40V.
 
Yes, that´s what I though. I don´t think the diference would be more than 28v on any transistor, so I should be fine.

As I´pve put some hard work on this, I think it would not hurt to ask, before I try it out and fry it.

Thanks a lot. I´ll let you know how it goes and if it sounds good. I hope it sounds nice, with 2n4401 and 2n4403. Those parts are regarded as very nice BJTs.
 
Yes, this is the circuit. I´m using the PCB version posted on your site. That large one...

Thanks for the heads up! :thumb:
 
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