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<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004>Laurie,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>In
general if you use the same parts you will have the same performance. Main
difference is circuit board layout. When you're doing SMT the traces are
typically smaller and closer together. This can create problems if you are not
careful. You'll need to pay attention to the amount of current that a trace can
carry (trace width) and to cross talk issues (distance between traces). With the
thin traces power layout and decoupling may be more of an issue. Pay particular
attention to circuits that are capacitive sensitive when doing layout and spread
the traces out. With traces that are carrying large signals you may want to run
guard traces between them or use distance. So keep these things in mind
when doing your PCB layout. Another thing which comes to mind is temperature
sensitive circuits like expo converters. With the smaller parts there is less
thermal mass which may make the circuits more acceptable to temp changes. So
thru hole/larger components may make a difference here.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>Some
other thoughts about doing surface mount stuff are:</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>Just
because you can get 603 parts doesn't mean you have to use them. You might use
1206 parts to start out with. With my eyes and hands I don't do anything smaller
than 805 unless I absolutely have to.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>If you do your own boards it
cuts down on the number of holes you have to drill. This can save a lot of
work.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>Clean
your boards real well before soldering.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>If you
are going to hand solder the stuff it will take some time to get a technique
down for doing it. So don't be discouraged if your first few tries don't come
out looking all that good. Keep working at it. I was forced into doing SMT at
work but once I was there it isn't all that bad.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>Having
a good temp controlled soldering iron, non-magnetic tweezers,
magnifier/lighting and plenty of tooth picks helps.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>I
found that having 0.015 dia. solder helps a lot if you can afford it. Having the
smaller dia. solder lets you control the feed better so you don't get more than
you need.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>Learn
the issues with and how to use water soluble flux solder it will make your
boards clean up real nice.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=053105703-02012004>Good
luck.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004>Jay</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=053105703-02012004></SPAN></FONT> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
owner-synth-diy@dropmix.xs4all.nl
[mailto:owner-synth-diy@dropmix.xs4all.nl]<B>On Behalf Of </B>Laurie
Biddulph<BR><B>Sent:</B> Thursday, January 01, 2004 1:25 PM<BR><B>To:</B>
Synth DIY<BR><B>Subject:</B> [sdiy] Surface mount<BR><BR></FONT></DIV>
<DIV><FONT face=Arial>Hi, Hope everyone had a good Xmas holiday and New
Year.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial>I would like to get some feedback on how you feel about
using surface-mount components in analogue synths as opposed to the good old
thru-hole component.</FONT></DIV>
<DIV><FONT face=Arial>Would two identical circuits built using the two
different technologies sound the same?</FONT></DIV>
<DIV><FONT face=Arial><BR>Best Regards<BR>Laurie Biddulph<BR><A
href="http://www.elby-designs.com">http://www.elby-designs.com</A></FONT></DIV></BLOCKQUOTE></BODY></HTML>