design Gibson Eb-750 Archtop Bass Projects

[Prostheta]

This is a project which will have a reasonably lengthy build-up time, so this thread exists purely to gather information, consolidate the design and work methodologies. A little background. I have never built an acoustic or archtop previously to this, so much of this particular thread will consist of my research and references to information online or from books, etc.

The Gibson EB-750 and its sister the EB-650 were extremely rare (less than 100) basses built upon the designs of the Gibson ES range. The EB-750 was (as far as I am aware) the same underlying design as ES-175 but with a bass neck and a bridge placed further towards the rear of the instrument.

My initial proposal is to build two basses, one with the same archtop design as the ES-175 with the longtitudinal braces and another with the more ES-335 style of build having a large solid central block between the arched back and top.

I predict that these builds will be more likely to happen towards the end of Spring or worst case towards Autumn 2013. In the meantime I will be examining and refining more of the project specifics including things like moulds, methods of making the sides (laminating/bending) and the all-important back and top carving. Hopefully throughout the process we can document and critique processes fully for the purposes of tutorials, etc.

Is anybody familiar with the EB-750 bass or in fact the ES-175? There is plenty of room for discussion on this one....

Cheers.

[Prostheta]

This repair article Frank Ford posted over on frets.com shows the internal structure of an ES-175. This was my initial starting point for the ideas on this project. Many custom archtop makers however, prefer the X-bracing approach. Which would be most appropriate?

I think that this may come down to whether or not I am laminating and pressing the top into shape or carving. Given that I want to amplify the instruments, I think laminated will be the better choice. There is the option of doing both however this may overcomplicate matters.

[Prostheta]

Okay, so from a fairly large amount of reading up on both X bracing and parallel bracing it seems that both are "appropriate". X bracing may be weaker from a structural perspective, being compensated with a thicker carved top. Should I decide to laminate rather than carve, this would immediately infer that parallel bracing is the better choice since laminating is an additive approach and carving subtractive.

The decision therefore, will be made on whether I want to work with a vacuum press over a form or carve directly from solid stock. Laminating would allow me the use of figured facing veneers over cross-grained plys of Birch whereas carving from solid would infer the use of large wedges of Spruce or Birch.

After I get back from the cruise I'll do better research into the cost of setting up a Venturi-style vacuum press system vs. that of buying split Spruce wedges or even using locally sourced Birch. I think the press will win out if it is reasonably affordable, since it will of course be re-useable.

[John Morciglio]

Hello,

New to the forum, second post.

I don't know if I should thank you, or curse you

Started playing guitar in 67' and bass about 71'.

Thought I was a gearhead and had seen everything.

This bass (and the 650), is NEW to me.

The Byrdland has always been one of my favorites. Have never seen a bass with the same layout.

Now I HAVE to build one and quick!

Have been working on Hollowbody carbonfibre archtops for a while.

Going to use the same body plug for a bass version. With a little less depth.

Now that I've seen this bass it will be my next project also.

Just kicking around if I should do it with carbon/wood neck, or go for an all wooden build.

Wood for me, would be much faster.

Been searching all over for es175 dimensions or plans. I would change the shape just slightly.

Anybody know if the EB750/650's are the same dimensions as the 175's??

Thanks

JM

[Prostheta]

I'll post better when we get to land. Currently pulling in Maarianhamina and slow WiFi.

[John Morciglio]

Can't stop searching for images, info, SPECS, plans.

Could have sworn I saw ES-175 prints on flebay?

There is also a Dean prototype dated 2010. with the same look/layout. Did not go into production.

Probably just use my templates and see where that goes. Tempted to do a quick carbon one-off.

Or a chambered mahogony with maple cap. Want to go with the semi-hollow/thinner format.

Already will be able to use my doublcut plug for a full-hollow bass.

The violin shape is another one thats tempting me for some reason. First 2 basses I had were a Hofner (hated it as a kid.

And an Echo knock-off. That one had a better set-up and feel at the time. (didn't know much back then).

JM

[Prostheta]

Phew. Hei John! Right, I have a bit more freedom to write this afternoon after a pretty hectic end to the week. I hate writing on the mobile since I prefer to be more verbose.

Curse me all you want about raising the EB-750 and EB-650 to your attention! I look forward to your input and experience with archtops since this is after all my first venture into anything vaguely in the acoustic camp. Most of my thoughts at the moment are with figuring out what tools and setups I need to be looking at and these seem to be defined with whether I am carving or laminating. I definitely need to look at either a bending iron or a heat mat setup for the sides either way. I guess laminating sides from veneers could potentially obviate this part. Even then with laminating throughout I would need to carve at least one former for the veneer press. On that basis I might make one of these two proposed instruments a carved Maple or Birch top for the acoustic properties (and trying my hand at the hollowing and carving) and the other a laminated veneer type for the amplification benefits.

Before we left on the cruise I was briefly looking at Venturi vacuum pumps as the basis of a laminating setup. I guess that your experience with carbon fibre will be extremely useful in this respect! My shared workspace is "industrial-level educational" and has many points around for compressed air so powering the Venturi will be no problem in the slightest. The challenge may be in finding heavy grade vinyl or other suitable material locally for making a bag. Any recommendations are welcome here.

As for the provenance of the EB-750, I believe it was patterned straight from the ES-175 however I have no proof of this. I can only imagine that Gibson re-tooling and creating patterns when an existing box would work perfectly well applies here. The only difference I could imagine would be the width of the neck at the heel joint perhaps altering the size of the cutaway, but it is no stretch of the imagination to presume that matching the width of the EB-750 at the 16th fret to that of the ES-175 at the 15th would be a matter of logic and convenience.

Is the Dean instrument you are referring to the Palomino? Yes, very much the ES-175 style!

For my own purposes I am planning on patterning the body cutaway from the specs of the neck backwards but based on this little bit of brainstorming it might be worthwhile looking at multi-purposing the mould for several sizes of Florentine cutaway. My primary instrument is 5-string bass, so it is not too much to imagine that this would bite me at some point if the archtop project is successful and a 5-string hollowbody bass would a lot of fun!

I haven't seen reliable plans for an ES-175 online as of yet, although they do exist. Since 100% authenticity is not a priority for me, I am happy with merely basing my dimensions on whatever specs I can glean and those which I prefer. The rough lower bout width, fret at which the neck joins the body, body depth (3-3/8") and perhaps scale length are all I need to work from. The rest is just designed out in CAD and turns out how it turns out.

Funny you should mention the Hofner "Beatle bass". I spent a few weeks working in a local music store doing repairs and setups, etc. and the go-to bass for a fun little jammer was an Epiphone Hofner copy. A lot of my playing style has been influenced by Claypool's strumming style though so it played into this really well. Perhaps an offshoot further down the line might be one of these. I should really put that out of my head before it sticks though really. Again I don't know whether to thank or curse you! hahaha

Isn't GAS a funny thing when you build instruments? 2013 is the year when one of my main focal points is to produce a "production ready" instrument design (original or not) from a set of specifically built jigs and machining operations. No hugely skilled hands, just a wood-in instrument-out idea....and I keep getting distracted by the lure of vanity builds....!

So yes, I'm looking forward to this one, John. I'm trying to work on documenting more on how I approach work so doing it right with experienced advice always makes it better! Ryan Juntunen elsewhere on the board has a carved archtop build on the go and he has advised me a bit on acoustic boxes up until now. He has a build thread on his HERE. Also, have you seen John Abbott's Byrdland-style build on here yet?

[John Morciglio]

Glad you made it back to shore.

Thanks for the links!

The Palomino was the same Dean. Prototype I found WAS a bass though.

Spent some time sketching in the shop today.

Should be finishing already built guitars, or working on customers bikes. It's the holidays right?

Printed pics off of Gibsons sight.

Claimed sizes of 16 x 20 and 17 x 20".

I can see two, if not, three different cut-outs at lower horn.

I like the Birdland best. But, 17 x 20 seems HUGE!. It scales to 21.7 long!

My archtops are 15.5" x 18.5".

It does not seem that big when it's all laid out. But I will definatetly shrink it up a little. Maybee 16x19.5"

I scaled the Birdland and used my templates to "fill in" the bout's and waist etc. Reduced about 1/2" from scale.

Not sure how many pics you can upload here, so I'll start another reply?

JM

[John Morciglio]

I rotated ALL those pics on photobucket???

Some show correct and some are still off when I view as slideshow??

Love the camera-phone. Took the pics with the phone oriented correctly. First time anything showed up upside-down.

Just realized. The "overhead shots", with the phone flat probably throw off the giro?

Think I will go for a neck-thru in mahogony with carbon strips for strength. Will keep it thin, 1.5 to 1 3/4" at edge. Round-over the back and full arch in front. Lots of chambering.

This bass was a "mock-up done over a couple weekends. I kept adding a little more till it was wired and stained.

It was also a "practice" carve and does NOT represent my finished work. I'll save the neck but the body will be cut off.

Home Depot maple.

This is the size I am going with on the full-carbon builds.

Checking for neck-dive to see if I could use the 34" scale. It balances nice but the body will be lighter in full carbon. Won't mind running a big "tone-block" under the bridge.

The guitar next to it is smaller, 14" and just built to see if it was worth persuing a full carbon build.

JM

[John Morciglio]

Checking ti see if it is right? Shows up OK on the photobucket?

Sorry about the fuzzy pics. Phone lens must be dirty.

JM

[John Morciglio]

[John Morciglio]

HMMM.

Sorry, where is the edit option?

Thanks for looking. Hope your not dizzy!

JM

[Prostheta]

Wow. Again, let me process. I don't work very well, quickly :-D

[John Morciglio]

Hope that works!

[Prostheta]

Certainly helps. Here are some of the photos I scraped online which I am using to provide the initial sketch/design:

[Prostheta]

I am planning on the full-depth of 3-3/8" from the EB-750 rather than the much shallower EB-650. Other than the soundhole design they appear to share common design characteristics.

[John Morciglio]

Dean image.

JM

[Prostheta]

Wow. Beautiful. That's exactly what I am after, except I will stick to a rear trapeze and modified bass TOM/archtop style bridge. I'm considering installing an LR Baggs element if I don't go the route of a TOM bridge.

That Dean looks like there is a central block, more like an ES-335 or at the very least some form of support for that hardware. Is it actually arched? It looks pretty flat from this angle.

Dean Prototype Hollow Body Bass - Never went into production

$799.00

Can't really tell you too much about this bass other than it has great sound, feel and action. This particular model never made it into production. There is a small crack in the back about an 1 1/2 inches long and a blemish on the bottom front edge due to a shipping mishap. Does not affect the playabillity of this incredible

One-of-a kind Bass !! Own a truly unique piece of

musical gear that will be the envy of all your friends.

http://www.tdwrulz.c...tarz--gear.html

[John Morciglio]

Are the mods./editors making my links come to life, or am I doing it correctly??

Doubt' if it's me. So, THANKS!

Can't find the EB650 anymore? It looked like the DG (Dave Grole) model 335. (Pelam?) blue.

Priced mahogony neck blanks and body blanks at the luthiers supply stores. WOW!

Can't find anything long enough for a neck-thru. And the body blanks are too small. The prices?? OUCH!

Really wanted to cap one with flamed or quilted maple. All the samples are Les-paul size. Not wide enough for an archtop.

May have to make the cap in carbon.

Have a veneer supplier (in Detroit) that has all kind of EXOTIC stuff.

Might take a trip to see what I can get and veneer the cap?

Reminds me of veneering MDF for custom cabinets and panels for libraries etc.

Makes me cringe a little.

Will be visiting my local mill tomorrow. He has the needed mahogany in 8/4".

JM

[John Morciglio]

That Dean is within 40 mi. from here.

What are the odds of that?

Called every dealer in Mi. I could think of. NONE had ever even laid eyes/hands on a eb650/750.

A rare beast indeed!

JM

[Prostheta]

Hi John - I edited your posts to directly reference the images :-D

Yeah neck-through blanks quickly get expensive from luthier's suppliers, especially for builds like Gibsons with neck angles. Generally if you are not going to see the whole length of the neck then laminating or going to set neck is satisfactory....especially for boxes when I perceive it easier to work on the neck and body separately until the final geometry and finishing work. I don't believe that the whole "continuous length of wood" argument has much stock as long as the joint prep and execution is done flawlessly. Much easier and cheaper that way than wasting a huge amount of stock just to get a neck-through blank from one piece. Are you genuinely thinking of a neck-through jazz box?! Crazy.

I suppose there is one way around the width of the figured back/sides, or at least a way that would work if you were going for a softwood top (more easily available) - splicing in a wedge between the two outer parts. Some luthiers even make them from three pieces which in many ways reminds me of how Sam Maloof made the seats of many of his chairs....!

Are you thinking of snagging that bass?

Yeah, I have considered the possibilities of veneering something nice since that is the best strategy for making hollowbody tops that resist feedback (other than a central through block). Snagging something like Ziricote veneer (personal favourite) would make a great natural instrument. I really want to make one in black though. I guess that is more down to Paul Barker having gotten me interested in the EB-750 in the first place. His recorded tone with Ministry was essentially an EB-750 through a Maestro BrassMaster and 70s SVT. The hollowbody seems to add the right qualities of woody growl for that combination to work better than a solidbody.

Realistically I would like one that builds on the acoustic qualities (limited though they might be) and one that performs better against feedback when amped. That would imply a blocked and painted box with a laminated top and the other made from solid carved woods. Since the back and sides have far less to do with the acoustics than the top then I believe these can still be laminated just with a carved Spruce top. Sounds like a reasonable plan of action.

What I have in mind so far is carving the top and then using this to create a negative mould for subsequent veneer pressing. Despite the ES-175 shape being an asymmetrical singlecut style the mould can still be made symmetrical for both backs and sides. I'd even be interested in no cutaways like an L-50. Depends on how much I enjoy working with acoustic and hollowbody boxes! Just my train of thought.

Hey, do you have any examples of your carbon fibre work to look at?

[John Morciglio]

Yes,

I am going for the semi-hollow. Chambered LesPaul type thing.

I have an Ovation custom shop 5-string with 34" scale deep bowl. (built to match my Elite).

Love having matching guitar and basses!!!

My Jazzbox molds will be made into a bass version. Full-hollow, or toneposts.

Got enough African mahogony today for 3 complete builds w/neck-thru for 177.50!!

When I whipped up that mock-up bass. Used some maple I had sitting around with the neck-thru. It was a VERY fast build. NOT finished to high standards. Will cut the "wings" off the body, and re-purpose the neck.

Got some "slotted and dotted" ebony boards on clearence. Still have one w/dots and one without.

It worked well for me.

Still in the finishing stages on 3 of these.

Strung up a couple to see how they sound and am BLOWN AWAY!!!!

Thanks for directing those links. Inspiration at a glance!!

JM

[John Morciglio]

These are coated with System 3 clearcote.

I use it to KILL pinholes.

Like to let it cure for a couple weeks before sanding back for final color and clear.

Have also been busy with a new model prototype bike and it is pulling me off the guitar building=(

REALLY FAST BIKES!!!

JM

[John Morciglio]

I won't be going after that Dean.

Rather build the 650 version.

Never really seen a bass or guitar that I, "had to have", like this one.

The Byrdland has always been a favorite so.....REALLY glad I didn't find a 650 for sale. Might have pulled the trigger on that.

I will e-mail the site to make contact with more local musicians.

Just started up building again. Not really trying to promote anything yet.

Figure it will take 5 or 6 to dial in the top lay-up to match a well-carved spruce-top. Or get close enough .

These have a really strong projection and my tops are WAY overbuilt, (too thick!) Good for hi-volume stuff I guess?

Also seem to have a "warm and bassy" tone. Thought they would be really bright.

Thanks again for the motivation,,,(distraction?

JM

[Prostheta]

Hahaha! I know exactly what you mean with the motivation/distraction thing! I often have to question whether I really should build X or Y build on the basis of "what will I learn or develop from it?". Thankfully I have a little wiggle room in my work schedule to plaster the odd vanity build here and there!

Wow, crazy recumbents there. Very nice work. I presume that CF work is your main (or one of your main) source(s) of income then? I briefly considered using a 0,7mm CF veneer for a fingerboard on a bass I have on the boil but decided against it on cost.