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Every design incorporates basic concepts; hardwiring and PC boards being included. In the old days, hardwiring was the staple of manufacturing. However, in the past 35 years or so, PC board construction evolved. Many have sought to return to "hardwiring", and rightly so, but not much attention has been paid concerning its shortcomings and if improvements are possible. When you consider solder contains some 60% tin (6 times the resistance of copper) and 35 to 40% lead (12 times the resistance of copper) one can see the importance of reducing solder connections. And if "simple" solder connects make a difference, what about internal wiring? What about layouts, resistors, capacitors, stray capacitance to ground and between parts etc?

For instance, just one 2uf capacitor on the chassis can have as much as 7pf between it and ground (called stray capacitance). Any capacitance to ground reduces the high frequency response and causes phase shifts. Imagine what multiple parts and wires on or near the chassis can do. One can imagine the stray capacitance to ground that robbs a component of its high frequency performance and the inconsistency problem, from unit to unit, during construction.

Now, what if we could minimize the shortcomings of "hardwiring" and use only the pluses of PC boards? We will have improved on a classic concept and better sonics.

Now, before we explain the differences, we must first discuss the pros and cons of "hardwiring" and yes, PC boards.

"Hardwiring"/ "point to point" wiring is simply connecting parts with wire and solder. However, this has the advantage over typical PC board constuction with foils in that:

• Wire generally has much less resistance than pc foil. For instance, a typical 1/16" wide PC foil is generally equivalent to a 29 guage wire. Two inches of 29 guage wire has about .014 ohms resistance. According to the specifications, this foil has 14 times, or more, the equalivant series resistance (ESR, DF) of a 1uf Realcap (copyright©) "Multicap" capacitor" (and typically other brands too). So using, say 18 gauge wire has some advantages.



• "Hardwiring" also has the advantage of being able to connect several leads/wires to one connection, thus eliminating solder connection(s). Typically, PC boards have individual holes for each part lead and separate solder connections, with foil in between. Thus many more poor solder connections are used in typical PC board construction than hardwiring. Typical PC board construction is unacceptable.

Now, let's look at the disadvantages of "hardwiring" in the practical sense. But first realize that we are dealing with nuisances - 40db and more down from the fundamental (millivolts or even microvolts region).

• "Common wires", that have more than one part connected to them present a common path and feedback, either positive or negative. A common buss ground wire is an example.



• Any distant parts require separate wires to connect them. For each distant part, at least one more wire and solder connection is necessary. And even large wire has some resistance.

One last point we need to look at are the 2 benefits that PC boards do have, which are:

• That the parts are consistently elevated above the chassis, thus minimizing stray capacitance between the parts and the chassis, for better consistency. Reducing the capacity to ground results in a higher frequency response, less phase shift.



• That wires can be nearly eliminated altogether, thus minimizing the number of solder connections.

The next page "Solutions To These Problems" will explain further.

*See "Picking Capacitors" by Walter Jung, Audio Magazine, Feburary, March 1980 for more information on capacitors.

* tm, sas audio labs, SAS Audio Labs,
SAS AUDIO LABS, and the SAS AUDIO LABS banner are trademarks of SAS Audio Labs."
copyright©: 12-28-1996 Updated: 07-16-2007. All contents of this article, including graphics, components, component layouts, "lead to lead wiring and lead to lead connecting", "Where Music Comes Alive" are copyrighted.
All rights reserved. No portion of this article may be reproduced without the written permission from Steve Sammet at
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