Tweed - BRIDGE PLACEMENT

Lots of the old (and some new) round-backed mandos use a straight bridge; but virtually all of the newer flatbacks, A and F style, use a very highly compensated bridge or bridge cap.

If you're stringing with "gut" or unwound steel or bronze wire, a straight bridge works pretty well; but if you use wound wire, the "end effect" makes the wire sound shorter than the "physical" length. The windings make the bending near the bridge really "lossy," so a little bit of the end of the wound wire wants to act like it's not part of the performance.

The G (low string) is a fairly skinny wire with a fat winding, so it needs to be physically longer than the next -
the D (second string), which is about the same "core" as the G but with a thinner winding.
The A (third string) has a skinny core, about like the E, with a fairly heavy winding - so it needs to be about the same length as the G, while
The E (fourth string) has no winding at all and needs to be "shortened up" a bit, about the same as the D.

The result is that the bridging point is set back (longer), about the same for the 1st and 3d strings, and about 1/16 inch forward (shorter) for the 2d and 4th strings. The typical bridge cap has a very visible zig-zag along the top to "compensate" the usual strings more or less properly.

If you can find unwound strings, you can adjust a straight bridge to pretty good compensation across the four strings; but if you're using (probably converting to, on an oldie) wound strings, you need to look at a new bridge, or a "cap" for the old one, if you really want good intonation on all the strings.

John