Old Gibson A's

[DrP]

Hi everyone

I'm looking at an old A4 Gibson, which has a nice sound and appears to be in pretty good condition overall. However, the top has sunken somewhat - doesn't seem disastrous, but the top is more like a plateau rather than a nice arch. Is this a big deal? Is there a simple way to check the structural integrity of the braces, etc, without taking it apart? Also, the bridge on it at the moment is a replacement - looks like a relatively cheap Loar style which is way too tall for the instrument. As a result, the action is quite high - could this contribute to the top sinkage? And if the bridge is replaced, can the top "rebound" to a more arched shape?

Any other common problems to look for in these instruments?

Sorry for the long post. Any information would be greatly appreciated.

[Tom C]

2 things I wouyld stay away from are a sunken top and a cracked back. Top being the tone, and a crack in the back can affect the structural integrity as that can cause everything to be out of wack.

[DrP]

How much sinkage is too much? Is there a "normal" amount of sinking one can expect on a mandolin this old? And is it reversible?

[Darryl Wolfe]

The a-models had a plateau shaped top..it curves upward from the tailiece and does sortof flatten for a while after it gets to the bridge. #Any sinkage becomes apparent about an inch or so before and after the bridge..that area should not look like it is going downhill hardly at all. The feet of the bridge will also look like they are distorting the top

check this pic from Elderly..the top has sunken by about the amount of threads showing on the bridge

[DrP]

Thanks very much Darryl - that sheds a lot of light on the situation! The one I'm looking at isn't nearly that bad, and seems more consistent with your description of the somewhat flattened arch. I was concerned because of the reputation that these mandolins have for top sinking, and the arch didn't look as pronounced as on a standard F-hole model. But based on your info, it may not be a problem. I'll have to take a closer look...

[Darryl Wolfe]

DRp..if you look closely in the pic, you can see the "crease" made by the tip ends of the bridge. A top that has sunken any will usually have a warble or crease out on the bridge ends..this is because the entire top cannot sink, only the central area

[DrP]

I think I see what you mean. Thanks again!