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Quick question: would you think that strings described as "chrome" or "chrome-nickel" are sufficiently ferromagnetic for magnetic pickups?
Reason I'm asking is that I currently have a set of ball-ended Optima Chrome strings on my Amazing. I had them sitting around for a while as they were misdelivered from a mail order: I had ordered several sets of loop-ended Optima bronze-wound strings for my bowlbacks, but one set happened to be marked "chrome" and had ball-ends. Look like steel. I meant to send them back, but never got around to it, so they seemed the ideal match when I converted the Amazing to a magnetic pickup and had to change its bronze strings to something ferromagnetic.
Now, the Optimas sound great and feel great, but I am a bit concerned that the wound strings are noticeable quieter than the plain strings, with the pickup mounted flat, same distance from all courses. Even the E-string, normally the problem on solid-body mandolins, is louder than the D and G. I wonder whether the windings on these strings are insufficiently ferromagnetic for the pickup.
Putting my physicist hat on, pure chromium is not ferromagnetic, it is antiferromagnetic instead (the only metal with that curious property). Nickel and iron are ferromagnetic. Thus, a pure chromium string would certainly unsuitable, an alloy steel with a bit of chrome would probably be suitable. However, I've noticed that string manufacturers seem to be using the descriptions "chrome", "chrome-nickel" and "chrome-nickel steel" interchangeably. Chrome-nickel steel may contain less than one percent actual chromium metal in the alloy, and would for all practical purposes be steel, i.e. ferromagnetic.
The Optima site is not clear on this: although the packet says just "chrome", the web site describes the same set as "chrome-nickel". Optima have electric guitar sets that are also described as "chrome-nickel", but it is not clear whether these are the same alloy as the mandolin strings.
I probably just need to get an actual steelwound string (say d'Addario J67) and compare its response to the Optimas to see if it is picked up better. If it's the same, I'll have to raise the pickup on the bass side for a stronger signal.
Just wondering if anybody here knows enough about stringmaking to say what sort of proportion of chromium is likely to be in a string marked "chrome".
Martin
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Can't offer a comparison, [would need to have tried both] but If there is just a plated surface on the winding material, for shiny appearance then I Imagine the magnetic properties would be adequate.
Chrome is kind of brittle on its own, wouldn't draw well thru dies ..
Nickel wound seems OK, nickel plated steel would be more ferrous, of course.
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Just an update on this old topic -- I did some side-by-side comparisons a little while ago with an Emando.com 8-string set, and can now confirm that the Optima Chrome strings are not suitable for magnetic pickups: they are very noticeably less ferromagnetic than steel-wound strings. Whereas with the Optimas, I had less signal on the wound strings than the plain ones, with the Emando.com strings I have the reverse (and I've changed pickup elevation accordingly). In retrospect that was to be expected, in view of the fact that stainless steel (17% chrome) is non-magnetic. So, for future reference, don't put chrome or chrome-nickel-steel strings on an e-mando, even if they look just like steel-wound ones.
Martin
