Gibson DM90 Dobro Duolian
Elliot
plated brass round neck model with a 9.5" resonator, biscuit bridge,
flat fretboard and stars and moon coverplate. It was in new
condition but I have read some posts on various guitar sites
complaining about the inconsistent quality of post-Gibson OMI's
however this instrument appears to be very well made. Perhaps the
problems occurred when they moved production out of California? The
DM33 looks similar except for the larger resonator, spider bridge and
radiused fretboard. I am puzzzled as to why they dropped this model
and went to the spider bridge on the 33's. From what I've read the
sound is very different. I really wanted a newer National but I got
the Dobro for a great price. All in all, I like the sound very much,
similar to a National O, but was wondering whether a Quarterman cone
replacement would be worthwhile. Would it make the sound warmer or
make the highs more prominant, or is the stock cone perfectly fine?
Is this an easy swap or would any modifications be required.
Thanks in advance,
Elliot Merkle
Tony Done
the Nat. Res. ones. I don't know the answer, but I would like to found out.
You infer that the high registers are not very prominent, and that makes me
think that a new cone might improve the sound. - The problem with resos is
usually weak bass response, not treble.
Another thought. there may be some kind of cushion under the cone, like
felt. If there is, I would take it out and expect to put some effort into
ensuring that the cone makes good contact with the soundwell shelf, for a
good sound and no rattles.
Tony D
"Elliot" <esme...@earthlink.net> wrote in message
news:5a270eeb.0303...@posting.google.com...
Kenny Pauzé
Hi Elliot, I would go with a National Reophonic cone for you Dobro
they sound much better than the Quarterman,
The Dye used for your Dobro is the same one that National used for their
14 fret guitars way back when so they should fit perfect,
This would be a much better improvement in sound than the Dobro cone
in my oppinion,
Kenny,
Kenny,
Elliot
some of the other information I've read about this guitar. A review
by Michael Messer also made mention of a heavy cone. A replacement
cone is only $50 from National and comes with the biscuit attached.
I assume that my bridge is glued to the biscuit. If this is the
case can it be removed without breaking it? Also, unless the new
biscuit is exactly the same height it would be necessary to sand the
bridge to maintain the same string height. This in itself is not a
big deal but how does one position the bridge correctly on the new
biscuit without knocking out the intonation? Is the bridge normally
glued or does the string tension normally hold it in place?
Elliot
Mike Dotson
The California-made metal bodied OMI guitars were very well made and finished
but the ones still lacked.
Mike Dotson
Oops, that's supposed to be 'Cones' not ones. Seems a week off the internet
has done nothing for my typing skills :o)
Tony Done
washer behind the screw, about 1/2" across, so that more tension can be put
on it without crushing the cone.
Intonation is a sometime thing on resos. The biscuit sits pretty much in one
position on the cone, or it rattles, but there is a little movement of the
cone in the soundwell. In old resos, the bridge is usually too far forwards,
so that the high frets are sharp; the cone should sit as far back as
possible, and the biscuit should be installed as far back as feasible on the
cone. On my style O, the saddle is actually behind the original slot. The
cone can also be installed so that the saddle is angled, as in a flattop,
and you can go even further and intonate the saddle itself, as in some
flattops. I put witness marks on the cone in the soundwell, and the biscuit
on the cone, so that I can get them back in the same place if I have to take
them out.
The top of the new saddle will also need lowering and shaping, as it comes
oversize.
Tony D
"Elliot" <esme...@earthlink.net> wrote in message
news:5a270eeb.03032...@posting.google.com...
Elliot
guys are a wealth of information. So, if I get this right, the
biscuit is simply screwed onto the resonator. Maybe I'm missing
something but I still am not clear on what holds the saddle/bridge to
the biscuit. Are is just held in place by the string tension or
glued? I really like the setup and intonation as it is now and do
not want to screw it up when I swap in the National Cone.
Mike Dotson
screwed to the cone. Not tightly, just snug, as the strings do the actual work
of keeping it in place.
Elliot
Thanks Mike,
I think I've got it.
Sounds like it would be easiest to do is just mount the entire Gibson
biscuit/saddle/bridge assembly to the National Cone, as long as the
height of the cone is same.
Elliot
Tony Done
Just a comment on attaching the biscuit. Mike clearly prefers the light
touch. This is the best approach if it works, but on a couple of occasions I
have found that the biscuit rattles on the cone or there is a loss of tone
due to poor contact. Firmer screwing, using a washer as suggested, may fix
it. If the problem persists, then I bed the biscuit in epoxy. - A thin ring
of epoxy on the biscuit, and plenty of release agent (I use a mixture of
beeswax and pet jelly) on the cone. Be sure to use witness marks if you do
this, and have the assembly upside down until the epoxy hardens, so that it
can't run into the cone.
The epoxy can always be sanded off the biscuit if there is a problem.
Tony D
"Elliot" <esme...@earthlink.net> wrote in message
news:5a270eeb.03032...@posting.google.com...
Mike Dotson
tension screws on spider bridge guitars I like to advise people to go at them
carefully.
Some people have used regular wood glue instead of epoxy to take up any small
imperfections between cone and biscut. The glue will stick to the biscuit and
conform to the cone, but not stick to it.
I've never had a problem so far and haven't tried it.
Kenny Pauzé
Yep! thats what I use, I used to use Franklins hide glue but since
running out I've swipped one of my kids Lepage's white glue,
I've had bad luck with Nationals buzzing there under the biscuit,
I believe National Resophonic makes the screw hole just the right
depth to secure the cone so that its less likely for someone
to overtighten them, but I guess theres some people who like to
really mash down on them!
Kenny,
Tony Done
release agent over the years, so I'm confident about using it. Two things in
its favour - it sets very hard (ie good acoustic contact), and it doesn't
shrink as it dries.
I think that Steve Evans uses hobby glue to seat the cones in Beltonas.
Tony D
"Mike Dotson" <ter...@aol.comNoSchpam> wrote in message
news:20030326174856...@mb-cp.aol.com...
Mike Dotson
release agent over the years, so I'm confident about using it. Two things in
its favour - it sets very hard (ie good acoustic contact), and it doesn't
shrink as it dries.
I think that Steve Evans uses hobby glue to seat the cones in Beltonas.
Tony D >>
You're right, if you're care careful epoxy is perfectly safe. I've glass-bed a
few rifles and never had one stick together yet.
Have you ever had to remove the cones from your Beltona? I'm curious how stuck
down they are. I guess I've been lucky but any buzzing I've ever had has always
been traceable to to string slots, covers/tailpieces or bad strings.
Guess either the Cone Gods favor me of those virgin sacrifices are working. :o)
Tony Done
you just stick your fingernail under them and lift very carefully. For the
benefit of others in the ng, this gluing only applies to tricones, because
there is no easy way to get leverage for removal on a single cone.
I've also bedded rifle barrels - trickier than reso biscuits.
Tony D
"Mike Dotson" <ter...@aol.comNoSchpam> wrote in message
news:20030327085428...@mb-fn.aol.com...
Kenny Pauzé
> I've also bedded rifle barrels - trickier than reso biscuits.
>
> Tony D
>
Tony thanks! I know how i'm going to fix my old shotgun,
Everytime I go hunting grouse I've got to bring along a screwdriver
to tighten her up after every shot!
Kenny,
Tony Done
held in place by an elastic band. Safe enough if the elastic didn't break.
I've actually bedded a db shotgun stock in epoxy, to get rid of some ugly
mismatches between metal and wood, and to get a bit more cast-off. It's the
gun I currently own, but I haven't used it for about 15 years.
Tony D
"Kenny Pauzé" <kb...@sympatico.ca> wrote in message
news:2fdb4e9c.03032...@posting.google.com...
Elliot
to remove, no prying required. There was no felt behind the old cone
to remove either, although there was a layer of dust on the Gibson
cone and inside the body which was easily cleaned out with the vacuum
cleaner. The old biscuit/bridge assembly sat completely flush against
the new cone so I just used the screw and washer which National
included and didn't bother with making an epoxy seat. After
reassembling everything I noticed that the intonation was out on the
bass strings. I measured the distance from each end of the bridge
to the fretboard and turned the bridge until it was perpendicular with
the strings. This corrected the intonation. The difference in
sound is incredible. I still cannot believe it. Not only is it
louder, but the highs just ring out and and the "flatness", or lack of
coloration is gone. The action is a bit higher because the cone is
slightly taller, but it can still be fretted, and the higher action
makes it easier for sliding, so I will most likely leave it alone.
If I change my mind I can always sand down the bottom of the biscuit
to lower the strings. Thank you to all of you for all of the great
advice, without which I would not have had the courage to attempt this
simple modification.
Mike Dotson
Tony Done
I'm pleased it worked out. AKAIK, opinion is still unanimous* that upgrading
the cone is worth the cost and effort, tho I would have expected the effect
to be more marginal than you reported on a Gibson, considering how much they
cost.
* Mike Hartman tried replacing an old National cone with a new one, and
didn't consider it an improvement - But I wouldn't classify that as an
upgrade.
Tony D
"Elliot" <esme...@earthlink.net> wrote in message
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Mike Dotson
to be more marginal than you reported on a Gibson, considering how much they
cost. >>
The cones that were (are?) supplied in the late OMI and Gibson-made brass body
guitars were crap. Not any better than the ones you get in a new Regal or
Johnson. In fact the poor quality was what spured Quarterman to go out on his
own.
Elliot
The Gibson cone was a plain saucer without the ridges of the spun
National cone. Does that mean it was pressed? I do not understand
Gibson. They build a nice metal body, add a quality nickel finish,
attach a solid neck with quality tuners, and install a junky cone.
What is wrong with that company?
Mike Dotson
National cone. Does that mean it was pressed? I do not understand
Gibson. They build a nice metal body, add a quality nickel finish,
attach a solid neck with quality tuners, and install a junky cone.
What is wrong with that company?>>
Don Young from the new National company worked for OMI and approached Bob
Brozman years ago asking him to endorse Dobro. Bob explained the changes they
would have to make, the cone being the #1 thing but thy just wouldn't do it.
Gibson probably sells everyone they can make and doesn't see a need to improve.
Mike