[sdiy] Minimoog tuning woes, Op-amp swaps?

[Neil Johnson]

On 2 Feb 2011, at 21:23, David G. Dixon wrote:

>> I don't know about the Minimoog in particular, but I have had  
>> students
>> working on projects who ran into problems when they replaced a 741  
>> with a
>> "better" op amp
>
> In that case, I say get the little darlings to run a SPICE model to  
> figure
> out the exact nature of the difference, so that they can make a more
> informed choice.

Please don't.  Instead, teach them about the requirements for op-amp  
stability, about phase margin, how to make op-amps circuits stable  
under various circuit configurations, etc.  Spice will show you a  
rough approximation of how  circuit might behave, but it won't tell  
you *why*.  Once they understand the *why* and the *how* is it worth  
exposing them to the temptations of Spice.

Ultimately Spice is a tool (and a very powerful one at that in the  
right hands) - but as with all tools if you don't understand the  
problem and what Spice can (and cannot) do, you just end up bashing  
the screw with the hammer.

Cheers,
Neil
--
http://www.njohnson.co.uk