Joanne,
First, keep trying with Linda.
Second: As for stringing with heavier strings, I'd definitely
check with her before doing anything of the kind. Mostly, I
agree with Paul's comments on restringing. I'd add one more
thing about that, too: should you restring it yourself,
be very careful not to move the bridge. That's mainly the
treble bridge, but the internal bracing probably is designed
for the bass bridge placed where it is. If the treble bridge
moves, however, you will not be able to have notes in tune
across the bridge. Precise route of strings from side rail
across bridge to other side rail is also essential for that
perfect fifth across the treble bridge. (Note that the
bridges are NOT glued down; in fact, Lost Valleys are
floating-soundboard instruments, with the top held down only
by the tension of the strings. I'd really avoid removing
large numbers of strings simultaneously, if I were you.)

General comments about Lost Valley (& yours from what you say):
My first dulcimer was a mid-1980s 13/13. It had three strings
per course on the treble, two per course on the bass. When
I bought a bigger dulcimer (16/16, mid-1990s) I bought another
Lost Valley. It's got two per course everywhere, & is lighter
than the 13/13 & takes less tuning. More recent ones yet
again have three strings on the treble (Paul's out of date on
that part), but are lighter weight than the older ones,
comparable to my newer one even with three strings per treble
course.

I didn't know she'd ever made instruments with four strings on
the treble courses & three on bass. Because of all this, I'd
be confident that your was an older instrument even if you
hadn't said how old it is. It's probably relatively heavy,
which is a serious minus if you need to carry it much.
(Floating soundboard instruments are normally heavier than
glued-all-around instruments anyway.)

Lost Valleys are relatively loud instruments. (Most players
consider this a plus. YMMV.) They have somewhat more sustain
than some dulcimers, though I've heard instruments with much
more sustain, too; I'd say they're probably average on that.
I prefer that sound, myself; but when I'm playing fast,
particularly in the lowest part of the range, it can get a bit
muddy.

I'm by no means the only one I know who traded up to another
Lost Valley. They're (IMO) more reasonably priced than some
comparable dulcimers - but there are other good instruments in
their price range. As Paul said, Linda's well respected here
in Michigan. I don't think she's made much effort to market
to a much wider area - probably able to sell what she makes
without doing so. They're well-built & attractively made. Some
of us clearly like the sound a lot. For those seriously jamming
or performing, the available dynamic range is good. They tend
to stay in tune better than average, in my own experience &
observation; I suspect (but don't know for sure) that the
floating soundboard is a bit less susceptible to temperature
& humidity changes than the glued-up design.

Beyond that, comparisons between different models are kind
of iffy. There are lots of very good instruments out
there, in a lot of different price ranges. They all sound
different from each other, & the sound one likes is a very
subjective thing. You really have to listen & decide what you
personally like. Some dulcimer makers are small outfits - Linda
and her partner Curt are an example - whereas some put out more
instruments by hiring helpers. That's neither better nor worse
(design, ability of those helpers, & quality control can make
the results good or bad); but larger shops do tend to develop
wider reputations.

Sorry to be so long-winded, but I don't see a shorter way
to answer this kind of question.

--- In hammered_dulcimer@yahoogroups.com, Paul Goelz <pgoelz@...> wrote:
>
> At 03:46 PM 6/1/2007, you wrote:
> >Hello, I'm new here. I am looking for some help with a Lost Valley
> >hammered dulcimer I purchased. It is 24 years old, and I contacted
> >Linda Foley, the maker, to get some details about it, but no one has
> >returned my call. The dulcimer needs restringing.
>
> Why? Unless the strings are severely corroded, they should not need
> to be replaced. Or are they missing? If just dirty / rusty, they
> can be cleaned off with a Scotchbrite pad and a VERY little WD-40 or
> similar very thin oil..... or no oil at all. Try using the
> Scotchbrite pad on them and then wipe them down with a rag that is
> slightly moistened with a thin oil. You don't want any excess oil or
> it will collect on the underside of the strings and make them sound
> very dead until you wipe it off.
>
> >The treble courses
> >have 4 strings and the bass courses have 3. All the strings are of a
> >lighter gage than on my other hammered dulcimer. Does anyone here know
> >what effect the lighter but more strings produces, versus having fewer,
> >but heavier strings? Do lighter gage strings tend to go out of tune
> >faster?
>
> My taste only, but I prefer the sound of three strings over the sound
> of just two. Having more strings to spread out the energy the hammer
> imparts seems to make for better dynamic range and a richer
> tone. But this effect can also be overwhelmed by the characteristics
> of any given instrument.
>
> >I am wondering if it is possible to restring it with slightly heavier
> >strings, but fewer of them--say 3 strings for treble and 2 for each
> >bass, or would this put too much pressure on the frame?
>
> I would not do that. For the same note, a larger diameter string
> will need to be tensioned higher, and the aggregate effect of 70-80
> strings at a higher tension might be enough to cause structural issues.
>
> >Lastly, does anyone have an opinion about lost valley dulcimers...the
> >sound they produce, their pros and cons, over other models. I have
> >shopped around a bit, I know nick blankton and mastercraft are
> >considered to be very good. but I have not been willing to put that
> >much money into a dulcimer yet, as I am still learning what I want.
>
> Linda is a well respected dulcimer maker in Michigan.
>
> The model you have is possibly a little louder and fuller than the
> current two string models she makes these days. Get it perfectly in
> tune (it might take a while) and see how it sounds to you.
>
> Paul
>
> Paul Goelz
> Rochester Hills, MI USA
> paul@...
> http://www.pgoelz.com
>