AW: To earth, or not to earth...

[Tim Cockram]

If the modules are star eathed i.e. a separate earth lead from each module to the central 
earth point, there should be no increase in crosstalk.  As a general point good earthing is 
essential.  My personal preference is a star earthed  Technical earth and a dirty earth for 
leds etc, logic is run @ +-7V5.  The earth "dustbin approach is also quite usefull  ( use 
an op-amp unity gain buffer with the non-inverting input connected to ground,  the output 
is a goood solid ground (limited by the outputs compliance).  The "dustbin" uses the high 
supply rejection qualities of the op-amp.

By symmetrical do you mean balanced Jurgen?

Right now I'm trying to decide weather to use 1/4" jacks or Banana sockets.  The only down 
side that I have come up nwith so far for the banana route is that in order to reduce 
interference the signal levels must be high (I'm allready using +-5v for audio) and driven 
from a low (ish) source impedance.  Therefore a module must have enough attenuatable inputs 
to negate the need for low level signals  (e.g.just a hint of a slow random voltage on the 
linear fm input of one of a pair of vco's).

Ideas, Comments  ?
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Tim Cockram
E-mail: tim at redragon.demon.co.uk 

Phone:-UK-1222-384041
Fax:-    UK-1222-390326


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