I'm going to do my best to not make this a "wut stingz are teh best and most coolz" thread. I'm looking for specific advice from people who know more than I do.

I just recently bought a Takamine EG523SC, and the stock strings are D'addario EXPs. No idea what guage, but definitely heavier than the Ernie Ball Earthwoods on my last guitar. The thing is... call me weird, but within a day of playing it, before even checking to see if they were coated strings, I could tell- the feel and the sound were both different, and I'm not sure I like them. I have a set of Martin 80-20 13-56's in my guitar case, and I'm really tempted to throw them on. The only thing stopping me is the worry that they might damage the guitar in some way, IE if the grooves in the nut aren't big enough or the tension might be too much. Am I being too overprotective of my new baby, or is this a valid concern? Buying a different set wouldn't be difficult, if that's the case.
I think you should check out a medium light gauge and throw those on there just to test it. Putting the wrong strings on a guitar not set up for it could be dangerous, especially on an acoustic.
why not contact takamine and ask? the 523 seemed heavily built enough to handle mediums to me, but it never hurts to get the official word.
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I just looked in my Oxford English Dictionary and under "Acoustic Guitar", there was your Avatar and an email address!
Quote by patticake
it never hurts to get the official word.


Or, you could take it in to a guitar shop and have them do a full setup for the .13s. These would be my first two options when you're not sure about this sort of thing.
Takamine says:

"We recommend the strings that came on the guitar from the factory. D'Addario EXP16 light phosphor bronze coated 12-53 strings. If you would like to use 13 gauge sets, you may need to have it setup to do so. We suggest ahving a professional gutiar tech put the 13-56 gauge strings on and so a neck adjustment and set up so that it does not hurt playability."

So basically what's already been said here.
Yeah, more or less. 13's are a bit heavy for most people. The guitar should be able to handle the extra tension but there is a good chance the slots in the nut won't be wide enough so the strings will stick. This is what the pro would need to fix for you because it takes special tools. The neck can be adjusted by anybody with a little knowledge and doesn't need to be done by a tech. If you don't have the knowledge I suggest you get a tech to show you how to do a truss rod adjustment because they tend to need done every 6month to a year anyway.
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