Transistor swap in GAR2520 opamp

[ben_allison]

I got the GAR2520 kit, and accidentally mixed up my BD139 and BD140. Desoldering from a through-hole PCB like this one is almost impossible! So, I had to cut them out.

I went to a local store to try and get replacements, but they could only offer substitutions:

BD139 > NTE375
BD140 > NTE374

Are these viable subs? Here are the datasheets:

BD139 (http://www.fairchildsemi.com/ds/BD%2FBD135.pdf)
BD140 (http://www.biltek.tubitak.gov.tr/gelisim/elektronik/dosyalar/40/BD140.pdf)

NTE 374 (http://www.datasheetarchive.com/pdf/getfile.php?dir=Datasheets-310&file=98911.pdf&scan=)
NTE 375 (http://www.datasheetarchive.com/pdf/getfile.php?dir=Datasheets-23&file=DSA-444528.pdf&scan=)

I'll order proper replacements if I have to; but since all I could get was these, I figured I'd see if they were usable. Thanks guys!

[pan60]

let me forward this to some of the tech we have that visit here: )~

[Dan Kennedy]

The NTE 374/5 pair should work.

They might be a bit slower because of their higher voltage capability, but it
probably won't matter in this circuit.

I've built 2520's with MJE-172's and 182's which are very similar to these
NTE parts.

[ben_allison]

Thanks for the info!

What will "slower" result in, tonally?

[pan60]

thanks Dan!

[mikekeith]

Not sure where you are but Newark has both...
Never been a big fan of NTE..maybe its me...
If its a critical part hand testing is the best way, but most don't do it..
And have to have a known good part to A/B..

But IF you have these..then you could use them and see how they perform...
Idle current would be something I would check for sure..Then go from there...
If you have no test gear then...

If it was me I would get the original, if they are different it WILL affect several things..