Decoupling chips

[Tony Allgood]

Matthew wrote:

> Hi Tony..
> 
> >
> > Just a thought, are you using half or full wave rectification. Full
wave 
> >should halve your ripple, but it will now be at 100Hz. And don't
forget to 
> >have separate RC filters on each chip or module. The more the
better. 47R 
> >and 10uF are nice. 
> >
> 
> On each chip? Is this overkill, or am I just being cautious? I'm just

> thinking that the more capacitance there is on the supply lines, the 
> greater strain there is on the PSU, particularly on startup...
> 

It doesn't cost much, and it will give you better line frequency
rejection. If you use quad op-amps, it's not so bad. However, keep
audio amps and CV amps separate, and don't let these share the same
filter.

Neve Audio do it with every op-amp! As do Marconi Instruments. Hey,
they even act like fuses if the op-amp decides to die.

As for PSU start up, not a problem if using 78/79xx as these have over
current limiting of sorts. And besides, the poor rectifiers have to
cope with a ot worse when you first power up.

Tony Allgood.

Penrith, Cumbria, UK     

e-mail: oakley at enterprise.net

'I may live in the middle of nowhere, but the views are nice'