AW: DIP packaged resistors???

[Haible Juergen]

Betreff:   DIP packaged resistors???

In building my analog circuits, I often have 1 or 2 heavily used 
resistor
values (like 100K) and it occurs to me that I could save board real 
estate
if I used a DIP packaged isolated resistor network in place of my 8
discrete 100K resistors.  The Mouser catalog offers these as thick 
film
resistor networks with 2% tolerance and TC of 100 ppm in a DIP 
package.

Aside from these obvious specs, can anybody offer any reasons why 
this
might be a bad idea????

Hmm, I don't exactly have an answer ... only thought about it myself 
some time.
I have bought some SIL packaged 100k arrays (Single In Line 9 pin; 8 
resistors
are connected to one common pin.) Should be optimal for CV summing, I 
thought.
2% is not that good (you'd want to have 0.1% for VCOs), but it's only 
the *relative*
matching that is important, especially if you use one resistor of the 
array as a
the feedback resistor in your CV summer as well. Only question is *how 
close*
are they matched relative to each other ? I measured two or three of 
them, and
they were very close, but this might have just been luck, and not the 
case in general.
So I haven't made use of these arrays so far, and still select 100k 
resistors for 100.0k
with the multimeter.
I've seen arrays in Moog synthesizer schematics, but I wonder if these 
are the same
ones which you can buy for cheap. Moog also seem to have used arrays 
with mixed
resistance values - never seen one of *these* in a store.

JH.
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