I recently built a Stratocaster and noticed that my 1st string sounds dead (even when played open) compared to my other strings.

Any advice?

All of my other strings ring out great. I play my B string and it rings like a bell, but my e string just sounds dull.

I thought that maybe the string wasn't aligned correctly over the pickup, but realized that my pups have no posts (They're Lace Sensors). I don't know if that makes a difference or not....
How long ago did you string it? After a few weeks (crappy strings) to a few months (good strings), they will wear out and become dull and lifeless. Try replacing it. They may wear out one at a time, which would also explain the just once string.
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chances are its hitting something in the bridge,..stock fender tremolo??..fixxed bridge??
If it was hitting something I doubt it would make any sounds at all. Or, maybe that's what thredstarter means.
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Everything is stock Fender Stratocaster. It has a Fender Tremolo bridge, which is "locked" down with 5 springs in the back, so I don't use a tremolo bar.

The strings are about 2 months old. They are Ernie Ball Regulars (the neon green package). I'll probably start with a new set of strings, then I'll have to look to spots of contact.

Just to make me feel better, what are the odds that it would be a pickup or wiring issue? I don't really recall noticing this before, but then again I wasn't exactly focusing on it...

I really noticed it when I was playing a part of a blues scale at the 9th fret, and went from the b string to the e string and noticed that the e string sounded dull compared to the bell like sound from the b string.
With 2 month old strings I would say that they are the issue. If it has been working up until now it is rather unlikely that the electronics would just malfunction all of a sudden, and only on one polepiece.

I have actually never heard of and issue with just one string if it's electronic. See how a string change goes.
Enjoi <--- Friend me
Quote by Scowmoo
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The action could be set up to low and just be touching the other frets possibly.
New strings should help.
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I have a strat with lace sensors and my B string doesn't ring out it just sounds muffled. Turns out the nut was cut to low. Options are buy a new nut or put a small piece of kitchen foil in the slot. Worked fine for me. If you are unsure of the cause it may be this...
I'm thinking that it may be a nut issue. I also get vibrations on the 6th string (low pitch E), which I blame mostly on the nut being cut too low. The vibrations only occur when played open and on the first few frets.