Archtop guitar conversion

**woodwizard** · Dec-17-2007, 12:32pm

I was wondering if anyone had thoughts good or bad on converting a Gibson L7 archtop to a mandocello. Would it sound good? Is it possible? Has anyone done it? Thanks in advance on any info.

**Alex Fields** · Dec-17-2007, 12:37pm

I played a mandocello that was a converted archtop...I wasn't that impressed. The low end was really weak and the range overall just didn't seem matched to the instrument. I don't know how much of that was due to that particular instrument but a 'cello does go a bit lower than a guitar, and you want a really strong low end for a 'cello. The conversion on the one I played was pretty rough but I'm sure it could be done a lot better so that you'd at least not have playability problems...still...unless the archtop just had a monster of a bass sound it seems like the results would always be kindof mediocre.

Now you can wait for an answer for someone who knows what they're talking about though and take my story for what it is--anecdotal.

**MikeEdgerton** · Dec-17-2007, 12:46pm

Does any archtop have a monster bass sound? Most that I have seen didn't.

**Alex Fields** · Dec-17-2007, 12:51pm

It seems unlikely.

**Jim Garber** · Dec-17-2007, 12:58pm

Jonathan Jensen of the Baltimore Mandolin Quartet has a converted L7 m'cello. I don;t think he did the work himself but it was done before he got it. It does sound quite good in his capable hands.

Frankly, tho, you would be ruining a perfectly good and relatively valuable archtop guitar to convert it. Quite a few folks convert Kays or Harmonys which are not super valuable.

They can sound quite nice in any case. Gibson's K5 mandocello was based on their L5 guitar. I played a Loar K5 quite a few years ago at Mandolin Bros.

**woodwizard** · Dec-17-2007, 1:03pm

It's sure not what you would call a bluegrass guitar. Like most archtop's it doesn't have that boom like say a Martin dreadnought. But it's not lacking for good tone when you're picking lead and does have good volume. It's a jazz guitar. I like it and have had it for a very long time. I have always wondered tho just what it would sound like as a mandocello. I've seen great pickers (Tim O'brian) playing conversions before that sounded pretty good and I know I've seen an article on this in the past but can't remember who did it. It's been too long and when you get my age #

#say no more

**markishandsome** · Dec-17-2007, 1:06pm

Oh for Pete's sake not an L7! If you really don't want it sell it to me! You'd probably have better luck finding a solid but expendable 12-string flat-top guitar and converting that.

**woodwizard** · Dec-17-2007, 1:35pm

It was just a thought. It's actually a beautiful guitar with an outstanding curly maple back, sides & neck although not completely original say for a collector.
Thanks all... I'll probably keep her as is. Have had it for 30 years and counting.

**Paul Kotapish** · Dec-17-2007, 3:14pm

Stefan Sobell modeled his first bouzouki after a 1931 Martin C-1 archtop--with a round hole. Those are wonderful--if highly underappreciated guitars--and many of them have been converted to flattop guitars. I think these instruments are fine just as they are, but if I were going to convert an archtop guitar to a bouzouki/OM/CBOM that's the guitar I'd try. And I think the tone qualities of that particular archtop design would lend themselves to a double-course instrument better than the f-hole Gibson design would.

The mahogany C-1 and the rosewood C-2 and top-of-the-Martin-line C-3 were a unique design that captured the high end projection of an archtop with a lot more of the sustain and boom associated with a dreadnaught or 000. The body shape is equivalent to a Martin 0000 or M, with a very wide lower bout, a narrower upper bout, and the approximate body depth of a 000.

**allenhopkins** · Dec-17-2007, 3:21pm

An alternative: get the Eastman 805 mandocello, built on their "800" series archtop guitar body, with slightly shifted bracing to accommodate the 'cello tuning.

A quality instrument, with spruce top, figured maple back and sides, bound f-holes, seven-ply binding around the top, ebony tailpiece. Less than $2K discounted. I got one a couple weeks ago and really like it. Not as sonorous in the lowest register as my K-1 Gibson, but LOTS of volume, very clean and clear, a good soloist's instrument. Neck is quite "guitary," might take some getting used to.

**Paul Hostetter** · Dec-17-2007, 7:40pm

Here's a Loar mandocello:

Standard 16" guitar body, rather narrow neck, inexplicably short (24.75") scale, not so suchamuch, except to look at. Well, I should qualify that: it depends on what you're expecting. I find Gibsons mandocellos generally thin and flabby because the scale is so short. A real cello has a 27" scale, and is designed around a C string that has authority. That's what I expect from a mandocello and I don't see it coming from shorter scaled instruments. Tune a guitar E down to C and you'll get an inkling of what I mean. Floppy strings don't do it for me.

Martin's C-1 made a fine mandocello (what PK was referring to, I think):

It used Martin's OM guitar scale of 25.4", which really helped. And it had a 10th fret dot!

Were you to convert a Gibson archtop to a mandocello, you'd have to consider the scale: usually they were 24.9"

So I wouldn't try it unless I changed the neck altogether. 17" archtops need a lot of string tension to drive them. Why wreck a good archtop guitar?

Vega mandocellos routinely had 27" scales and they sounded fantastic. But Vega didn't make very many.

**delsbrother** · Dec-17-2007, 7:59pm

Wow, anyone know how many of those Martin made? Any survive?

**EdSherry** · Dec-17-2007, 8:24pm

I echo Allen's suggestion: #I have an Eastman 'cello built along the lines of the Gibson K-5: #an archtop guitar body (akin to an L-5), with an 8-string neck. #It has an extremely powerful bottom end. #

I'm not sure I'd recommend converting an L-7; I'd second the suggestion that there are plenty of Kays and Harmonys around to experiment with.

**Jim Garber** · Dec-17-2007, 8:47pm

Originally Posted by (delsbrother @ Dec. 17 2007, 19:59)

Wow, anyone know how many of those Martin made? Any survive?

According the the Longworth Martin book, there were 3 MC-1 mandocellos made in 1932 and 2 in 1935.

There were also 2 mandocellos made in 1932 based on the C-2 guitar body. These had rosewood back and sides.

Here is a MC-1 that was on ebay back in 2004.

**Paul Hostetter** · Dec-17-2007, 9:43pm

Charles Johnson got one off eBay last March, a Style 2, that wasn't anywhere in Longworth's survey.

**steve V. johnson** · Dec-17-2007, 10:15pm

Wow, I had no idea about the Martins, thanks for that info! Very cool.

Tangentially, a number of builders have done octave mandolins and m'cellos based on the Gibson L guitar designs, albeit modified.
I recently played the recent one by Andrew Mowry, a scaled-down L5 design in spruce/maple, a super sweet one.

My reflex was similar to markishandsome's, but with a bit less energy. I'd let the L7 be an L7 and make another one in a
variation, from a different guitar or from scratch.

Nice thread, a lot to learn, thanks,

stv

**Big Joe** · Dec-17-2007, 10:55pm

Your L7 would make a great mandocello, but there are others that are not as valuable that may be a better choice. I have a bit smaller arch top converted into a mandocello. There is more than enough bass! Dave Harvey has a recent L7 converted to a mandocello and it plays and sounds great. I don't know that I would recommend altering your L7, but the good news is that if done properly it could be taken back to a six string in the future if needed with some minor modification. The main adjustment is to plug and redrill the headstock for eight tuners.

**woodwizard** · Dec-18-2007, 12:30am

Her's a couple of not so good pics of my '47 L7 serial # A212. I think I'll leave it alone for now. As I mentioned before ... I 've had this one for quite a long time. I have it set up pretty good where it plays easily and it does sound pretty good. I still remember when I got it in a yard sale close to 30 years ago. Best deal I ever made ... 20 buck$

**woodwizard** · Dec-18-2007, 12:35am

and another shot

**Michael Lewis** · Dec-18-2007, 2:26am

A previous post stated that archtop guitars don't make much low end sound. That should be changed to MOST archtops don't make much low end sound. The best example to refute the original statement is a Steven Andersen archtop with the oval sound hole high in the upper bout. These are tremendously bass heavy. It is due to the fact that the air chamber is contained pretty well (not open in the middle, like with F holes) and acts like a long tube. The low end comes out of the air resonance more than the wood resonances.

One main problem with short scale 'cellos is they probably have strings too small for the tensions and frequencies they are used at. Real 'cello strings designed for the 27" scale will not make the sound you are looking for if you put them on a 25"(or less) scale instrument. I have been making octave mandolins with either 20" or 23.5" scales, and they take significantly different strings, the shorter scale needs much heavier strings.

**MikeEdgerton** · Dec-18-2007, 8:46am

Originally Posted by

The best example to refute the original statement is a Steven Andersen archtop with the oval sound hole high in the upper bout.

I've never spent any time around any arched top guitars that didn't have F holes. I can imagine that an oval hole Arch top guitar might actually have some bass to it.

**Bernie Daniel** · Dec-18-2007, 10:47am

Here is a conversion guitar to mandocello I did.

This was before I finished up the bridge - have a rosewood one now.

The problem is the neck. Too wide. But if you play this thing for 30 minutes you think that you are Sam Bush on the mando it is soooo easy.

**Bernie Daniel** · Dec-18-2007, 10:49am

Sorry here is a full shot. It bumped the second .jpg.

**Paul Hostetter** · Dec-18-2007, 2:12pm

Mike - I have spent a lot of time around archtops, and I think the soundhole situation has little if anything to do with bass response. Archtops specifically built as acoustics -- which lets out most anything built between 1937 and 1990 unless made by John D'Angelico -- are fairly rare. Most, like Gibsons and so on, were deliberately overbuilt so they wouldn't feed back when they were plugged in - whether they were sold with a pickup or not. This means most 17" archtops. We're thankfully in a renaissance of acoustic archtops, which done right, can do anything and have lots of bass to go under the treble.

**MikeEdgerton** · Dec-18-2007, 4:04pm

Originally Posted by (Paul Hostetter @ Dec. 18 2007, 14:12)

Mike - I have spent a lot of time around archtops, and I think the soundhole situation has little if anything to do with bass response. Archtops specifically built as acoustics -- which lets out most anything built between 1937 and 1990 unless made by John D'Angelico -- are fairly rare. Most, like Gibsons and so on, were deliberately overbuilt so they wouldn't feed back when they were plugged in - whether they were sold with a pickup or not. This means most 17" archtops. We're thankfully in a renaissance of acoustic archtops, which done right, can do anything and have lots of bass to go under the treble.

That all makes perfect sense.