Re: gEDA-user: Re: Pointer to 3d CAD?

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Wed, Nov 01, 2006 at 10:58:02PM -0500, DJ Delorie wrote:
> 
> >    It all depends on what you're into.  I've been discussing a
> > project with a friend that would involve building what amounts to a
> > copy of the PDP-8 ("Straight-8", no suffix) with individual
> > transistors.  It's fun, cool, and highly educational in a number of
> > areas.

Now I am rebuilding the Ronja receiver with individual transistors instead of
the NE592. The dynamic range was low, the chip operated out of the specified
thermal range and you had to pick up transistor pairs with similar
amplification.

Only now I discovered the beauty of symmetric limiting amplifiers, current
sources and cascode configuration. Now I have two stages, the first is
4-transistor and the second 6-transistor.  I want to make 3 stages, 6
transistors each and today I have to go into a shop again for another 10
transistors, because I have just 1 left here.

Transistors are cheap. Transistors are fast. Transistors have almost unlimited
operating temperature range.  The manufacturer doesn't keep the secrets of
operation away from you. You can implement interesting functions by clever
arrangement of them.

I am looking forward to the day when the receiver will be finished and I can
place a "fully transistorized" and "19 transistors" retro labels on them :)

Finally people will stop asking "where can I get that NE592 circuit"
and "my Ronja doesn't work on short distances". Does it matter if you solder
14 pins of NE592 or 5 3-pin transistors?

CL<
> 
> Are you going to be true to the time and use TO-92, or "cheat" and use
> SOT-535's?
> 
> The Museum of Science in Boston has a computer that plays tic tac toe.
> It's made of wooden Tinker Toys.
> 
> 
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