Transistor Substitution Question

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abby normal

Well-known member
Joined
Feb 20, 2008
Messages
364
Location
USA
I'm in the middle of building a Country Hick DI box and it's calling for 2 2N4401's. I've never worked with these before and there's none available locally. I would like to finish this one up this weekend to boot and save a shipping charge if ya know what I mean?  :'(

Is there a good equivalent in the run of the mill varieties? Low noise etc.  I have a pile of transistors and thought I had this one, no dice...

http://www.diyfactory.com/projects/countryhick/countryhick.htm


 
It is a small Si transistor.  If the circuit is designed correctly a lot of different small signal NPN Si transistors should drop in and work

The bottom 2n4401 is setup as a CC source, the junction drop - one 1n4148 drop and + one more 1n4148 drop / 270 ohms.  So about .6vdc/270 ohms about 1.8ma CC.  Knowing that you can calculate the power rating of the output transistors with the supply voltage you will use.

Or look up the specs and see if a 2n3904 or 2n2222a or pn2222 or 2n5088 or ... will work

The linked circuit is a SF into a EF with a CC source in the emitter leg less than a gain of one I don't think low noise matters.
 
Thanks Gus, Pucho. With 18V I'm coming up with 40mW dis. and these all are in the hundreds plus so it looks like I'm in the pink. The 5088 is the all around performer out of that lot and I have a bunch on hand so I'll head in that direction unless someone says different.

Hey Pucho, be careful on those NTE cross references. NTE wants to sell you everything and the kitchen sink. You could cross reference a hundred transistors and NTE123AP will pop up. I learned that one the hard way...  :-[
 
quote from abby normal:

  Hey Pucho, be careful on those NTE cross references. NTE wants to sell you everything and the kitchen sink. You could cross reference a 
  hundred transistors and NTE123AP will pop up. I learned that one the hard way...  :-[
  [/quote]

Boy no kiddin'!  I tried their suggestion in an LA-4; smoke, fire, and amusment ensued.

If the part has the same number of pins, NTE figures it's a match.
They pretty much piss me off.  Big time.

Of course they are the only choice in some cases.
 

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