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Subject: Re: Possible strange question about SMT

From: "Paul Schreiber" <synth1@...>
Date: 2005-08-17

> I have no opinion about SMT in general so this is not a critical post - just a
> question. I have wondered for some time if the physics of smaller parts -
> like SMT parts - and I guess transistors especially, causes them to respond
> differently in VCOs, VCFs,

Errr....no.

a) for one thing, SMT is 99% a ∗mechanical mounting∗ thing, not a silicon thing.
For example, the axial 0.1uf bypass caps in the kits today are ∗actually∗ SMT
chip
caps with leads attached :) In fact, I can argue that the leaded bypass caps are
∗degraded∗ SMT caps.

Also, the DIP ICs were are using now are using the ∗exact same die∗ inside as
the SMT parts do. All that changes are the 'pins', and that comes into play at
frequencies over 400Mhz.

b) so, the only 'concern' is caps (in the audio path) and the resistors. Well,
resistors
in SMT are just as stable and just are reliable (if not more, because SMT reflow
soldering is much more reliable than thru-hole, especially in
high-shock/impact). That
leaves the caps. In situations where I feel the circuit is ∗better served∗ with
a certain
thru-hole cap, then that's what I will do. There is no "rule" that every part
HAS to be SMT,
it's just cheaper that way. But the pots and wires are thru-hole, so much for
that :)

Remove the tin-foil hats!

Paul S.