[sdiy] CMOS chip questions

[Tom Wiltshire]

On 19 Jul 2009, at 19:13, Scott Gravenhorst wrote:

> "David G. Dixon" <dixon at interchange.ubc.ca> wrote:
>>> Why Would one need any TTL interfacing? Just tell me what's  
>>> missing on
>>> CMOS replacements for TTL chips. It's probably 7404?
>>
>> Samppa's definitely got a point.  Mixing TTL and CMOS is kinda  
>> like putting
>> '74 Chevy Impala parts in your Acura TL.
>
> There are times when one needs more drive current than CMOS  
> provides.  One way to deal
> with that is parallel drivers, but another is bipolar TTL.  I guess  
> it depends on
> exactly how much current one needs.  I think, however, that for  
> most synthesizer
> designs, such currents are more rare than common.  Stepper motors?   
> But who puts a
> stepper motor in a synth?
>
> Maybe some exotic thing that uses electromechanical vibrating parts  
> excited by a synth
> circuit?  (reaching)
>
> -- ScottG (who waits to find out about stepper motors in synths)

Funny that you mention it but...

We were talking at SDIY UK about the perennial problem with  
programmable synths - once you load a program from memory, the knob  
positions don't tell you anything anymore.
The suggestion was made that the absolute best way around this would  
be to have motorized controls for the entire front panel, like some  
top-end mixing desks of old.

T.