I didn't mean to challenge your design decisions Paul - sorry if it
sounded that way. I'm quite happy with MOTM - as I said, I think it is
king of the synth world. The info below is very interesting, eg. the
fact that the dies are the same for SMT and DIP ICs - which makes sense
from a manufacturing point of view. I was thinking more along the
lines of what Mike mentioned about electrons interacting with the
components - thinking about whether there would be any difference in
the sound of a ckt design realized with discrete components vs ICs.
It seems unlikely that MOTM will ever use custom LSI or VLSI (or
SuperDuperLSI or whatever we're on now) ICs, like Alesis did with
Andromeda, so this whole question may be moot as far as MOTM goes...
Larry D.
BTW, does anybody know what Dave Smith Instruments uses for the analog
VCO/VCF in the Evolver line of synths? The sales lit. suggests that it
is CEM chips, but that seems unlikely unless they got someone to make
them again (or don't plan to sell many units??)
On Aug 17, 2005, at 12:48 PM, Paul Schreiber wrote:
>> 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.
>
>
>
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>
>
> Yahoo! Groups Links
>
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>