Todd Bailey wrote:

 >> Recently I started designing a discrete BJT op-amp (my first time) for 
an
 >> audio circuit, and in doing so have been studying the manufacturers'
 >> schematics of different monolithic op-amps.  In several of the circuits
 >> (the 741 [Horowitz and Hill, p.189] and the 5532
 >> [http://www.dself.dsl.pipex.com/ampins/webbop/5532.htm] so far) I have
 >> seen components drawn into the schematic which look like a normal BJT
 >> with an extra collector or emitter leg drawn on.

Gerhard wrote:

>I'm not sure what you are trying to do, but it seems to me that the
>techniques to use when building an amplifier from discrete components are
>quite different from the ones to use when creating an integrated circuit.
>The "components" available are just too different in the two cases. Also
>don't forget that the schematic of an integrated circuit is something like
>an approximation; this becomes more obvious when you look at the actual
>silicone layout.

>If you want to build a discrete audio amp, you are probably better off with
>some literature about discrete amps, rather than studying schematics of
>integrated opamps.

>Gerhard

---------

  I'm afraid I don't know very much about the intricacies of integrated 
circuit design, but it seemed to me that, generally speaking, the 
manufacturers' datasheets were a lot more exact about the specs and theory 
of operation involved with their devices than audio experimenters.  So I 
naturally gravitated towards those and H&H rather than audio DIY websites or 
Delton T. Horn books or the like.  I'd really like to learn the theory 
behind what I'm doing, especially since the components involved in discrete 
design can be so pricey and there are so many opinions on the subject 
floating around.
  That having been said, what you say seems believable.  Could you recommend 
a good book or reference on the technical issues of discrete op-amp design?  
I've found a few web sites, but that's it.

Yours, and thanks again,

Todd


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