Advanced Jumbo Question

[j45nick]

Hello Red 333.

 

A serious line up – it's appreciated.

 

Well they don't seem to differ much, and as you say, small marginals can come down to weather, sanding etc. Yet I'm almost certain my now gone '08 AJ was more longish than the '10 J-45. Despite of optical factors as rosettes, guards even bursts.

All in all a good topic that deserves attention, and hopefully others will contribute.

I'll be the last to hyper-protect the idea the models are more different than stated above, but the sight of that AJ just won't leave the back of my brain.

 

Apropos :

In fact I threw an eye on my square shouldered G's some 10 days ago and noticed they had various measures over the shoulders (a little comment on 45Nicks words in the J-45 case thread – and welcome back Nick, hope to read you some more). Thought this discovery was worthy of a thread, but didn't have time and strength to set it up as it would take some waist and hip measuring also.

Of course it must be done at some point – Have 5 of those here in the temple.

 

Look forward to any opinons -

 

I think it's almost seen here -

 

Approx. the same angle - , , , and scale if judged by the pins.

 

 

This is a topic close to my heart, as I had a terrible time finding a case to fit my late-40's J-45 a couple of years ago. At least in my experience, the slope jumbos vary quite a bit dimensionally, although within a fairly narrow range.

 

I also have the J-45 plans from Stewmac, which everyone with an interest in the J-45 should own. These plans were taken off very precisely from a 1957 J-45 by Michael Collins, and have an extraordinary amount of detail, including all the braces, the bracing pattern, the various bridges, neck profiles, the primary two pickguards, etc, etc, etc. The drawings are all full-scale, and there are four sheets showing every possible detail of the 1950's J-45.

 

This variablity, by the way, is not limited to Gibson acoustics. The ES-335, in addition to its designed varieties of "horn" shapes over time, varies in body depth without rhyme, reason, or year by 1/4" (6.3mm) on a constant nominal body depth over time of 1.75" (44.5mm).

 

For reference, below are key body dimensions on my late-40's J-45 (FON 3644 8), compared to the 1957 Collins plans. My J-45 is kept at a relative humidity of 44% in the summer (air conditioned house),but that climbs to as much as 65% at times in the winter if it is raining outside and the windows are open. I just checked these dimensions today and compared them to the last time I checked them two years ago, and there is virtually no change, so this guitar at least is dimensionally stable after almost 65 years.

 

reference:..... Nick's J-45:..... Collins 1957 J-45

 

 

body length .... 20 1/4" (514.4mm) .... 20 3/16" (512.8mm)

 

 

depth min .... 3 3/4"+ (95.5mm) .... 3 7/8" (98.4mm)

 

 

depth max .... 4 3/4"+ (121mm) .... 4 7/8" (123.8mm)

 

 

LB width .... 16 1/4" (412.8mm) .... 16" (406.5mm)

 

 

waist .... 10 7/8" (276.2mm) .... 10 5/8" (269.9mm)

 

 

UB width .... 11 5/8" (295.3mm) .... 11 9/16" (293.7mm)

 

 

 

 

As an aside, some of you know that my guitar was re-topped by Gibson in 1968. The top bracing pattern of my 1968 top is identical to that of the 1957 Collins guitar, although some of the brace sectional shape and brace end scalloping is slightly different from that of the 1957 J-45. It would be most interesting for someone with a late-40's J-45 to compare their top bracing to that of the Collins 1957 plan.

 

The back bracing locations in the Collins plan are identical to those in my old J-45, but the sectional shape is dramatically different. My old J-45 has back braces that are much taller and thinner than the 1957 back braces in the Collins plan.

 

Sorry the data above is so hard to read. There is no text editor that allows me to space things properly that I can find here.

[Red 333]

This is a topic close to my heart, as I had a terrible time finding a case to fit my late-40's J-45 a couple of years ago. At least in my experience, the slope jumbos vary quite a bit dimensionally, although within a fairly narrow range.

 

Very interesting, Nick. There's no doubt there's probably more variation in pre-CNC, guitars. Still, I think the measurements from your actual guitar, the plans, and my post-CNC guitars are very consistent, with variations of only 1/32' or 2/32" here and there. I mean, we can think of thousand of products and situations where those kinds of variations would be disastrous, but in a guitar body--as long as everything that's supposed to be glued together is--not so much, I think.

 

The greatest inconsistencies between the measures you provided and mine are in the waist, and that may just because of the method and tool I used to measure, which was a steel carpenter's tape. The flat tongue has to lie on a curved surface, so my measurement was probably a bit larger than actual size. While my figures show a waist that is somewhat thicker (true of everything American since the '40s), there's internal consistency between the supposedly accurate Legend and the TV's, Texan's, or either AJ's, etc., suggesting that the jumbo shape has not changed too much.

 

The big difference in Gibson family jumbo shapes has until recently been with the Pac-rim made acoustics (Epiphone Elitist series excepted--they were always correctly shaped). While resembling the Gibson jumbo shape, Pac-rim Epiphone acoustics have been much shorter, had a wider waist, measured shorter across the widest part of the lower bout, etc. More bean shaped in general. Epiphone began using Gibson jumbo dimensions with the release of the Inspired by Texan a couple of years ago. That shape has spread into the Masterbilt line, the EJ-160E by most reports, and to other guitars, as well. As I mentioned, the short-lived Elitist acoustics (the jumbos were the J-45 and Texan; there was also an EL-00 and a J-200) were very close copies.

 

There's lots of reasons ES-335 dimensions vary, from the gradual spreading of the original forms that the rims were pressed from, to copying those expanded forms as production needs demanded, to an actual redesign of the horn in the early 60's, etc. That's another topic that fascinates me. "The Gibson 335--It's History and It's Players" by Adrian Ingram has some interesting insight into the causes of different variations. The ES-335 is my favorite electric.

 

I'm going to have to get a set of those Collings plans someday. They sound cool. My birthday's coming up, so I'll ask for them.

 

Good to see you here, Nick.

 

Red 333

[E-minor7]

Short scaled J-45 has 6 + an 'emty' zone. AJ has clean 6.

Red 333 -

Thanks for nominating me for good eye-sight, but the above was clearly nonsense. As you say, frets are simply 6 to 5.

 

Casting a glance on my 1966 C&W, it's more like a D-28 than the regular Gibson square. WHAT ! . . .

[Red 333]

Red 333 -

Thanks for nominating me for good eye-sight, but the above was clearly nonsense. As you say, frets are simply 6 to 5.

 

Casting a glance on my 1966 C&W, it's more like a D-28 than the regular Gibson square. WHAT ! . . .

 

The C&W got square shoulders in 1963, I think. The J-45/50 got 'em in 1969, and they remained that way until production stopped in 1982. After a hiatus, J-45's were reintroduced with round shoulders in 1984.

 

Red 333

[E-minor7]

The C&W got square shoulders in 1963, I think. The J-45/50 got 'em in 1969, and they remained that way until production stopped in 1982. After a hiatus, J-45's were reintroduced with round shoulders in 1984.

 

Red 333

Thanks, that I more than know.

What I'm talking about here is one of my 5 squares, which - as you understand from post # 20 - are all more or less different over the shoulders.

 

The square shouldered Country and Western SJN, as the sq. sh. Southern Jumbo and the Dove, first saw light of day in 1962.

[j45nick]

sorry. Accidental bad edit.

 

I did point out that the changes in the horn designs in the ES 335 were conscious, and I was not referring to them in terms of inconsistency. What is inconsistent in the ES 335 is the body depth, which varies about 15% from instrument to instrument, when it is nominally the same. In fact, Charlie Gelber in his ES-335.net blog recently had a discussion of this. Since the ES-335 has a solid center block that must be shaped to suit the depth of the rims, this inconsistency had to slow down production quite a bit if each center block had to be planed to the proper depth of each rim set.

 

I don't know what the production process was for the slope J's in Kalamazoo, so I don't know if the tops were individually fitted to each rim set from oversized rough blanks, or what. This could make a substantial dimensional difference, depending on the humidity when the rim set was released from the mold and the back and top fitted. Once they come off the mold and the back is glued on, the shape is pretty well fixed. Kalamazoo was neither climate controlled nor consistent in humidity and temperature, which could explain some of the differences, along with the somewhat greater amount of hand work in the pre-CNC days.

 

I just happened to get a J-45 that was a bit larger in every dimension except depth, which made case fit a bit difficult.

 

This is not a criticism of Gibson in any way. It just reminds you that at least in the old days, these were largely hand-built guitars, despite all the jigs and machinery, some of which still carries over to the Bozeman plant, according to the videos JC posted here recently about the current Gibson production process.

 

Frankly, I love the inconsistencies, as they may translate into tonal differences of the same order of magnitude introduced by the variability in the wood itself. There may be a "standard" mahogany slope tone, but the variations within that are endless, at least in my limited experience.

[E-minor7]

Are you asking if the contemporary J-35's body is the same as the AJ's? Yes. I can't say conclusively about late 30's/early 40's models, if that's what you're asking (since I don't have any), but it SEEMS like the jumbo body has been pretty consistent in dimension since its inception, if it is to be believed that the contemporary AJ and J-45 Legend replicate vintage instruments exactly.

 

I read several places that the waist was narrowed in (from the Jumbo 35) back then.

On a vintage page and in the Fabulous Flat-top Guitar bible.

 

[Red 333]

I read several places that the waist was narrowed in (from the Jumbo 35) back then.

On a vintage page and in the Fabulous Flat-top Guitar bible.

 

 

Do you know what page it says this on? The only reference I could find is on page 48 of both the First and Second Editions, where the authors describe the AJ as having a narrower waist (10 11/32") than the OJ, the model that preceded the AJ and J-35, which were contemporaneous models.

 

Thanks.

 

Red 333

[Red 333]

 

 

I just happened to get a J-45 that was a bit larger in every dimension except depth, which made case fit a bit difficult.

 

 

 

Yeah, looking more closely at your measurements, your J-45's waist is almost 1/2" wider than the average of my contemporary slopes and the measurement for the AJ's waist in Gibson's fabulous Flattops, and 1/4" wider than the Collins plans indicate. That does seem like a lot. I didn't measure the width of the top at the bouts on mine, but it follows that the perimeter dimensions on yours may also be enlarged, like the waist. How did you finally solve your case conundrum?

 

Red 333

[E-minor7]

Do you know what page it says this on? The only reference I could find is on page 48 of both the First and Second Editions, where the authors describe the AJ as having a narrower waist (10 11/32") than the OJ, the model that preceded the AJ and J-35, which were contemporaneous models.

 

Thanks.

 

Red 333

Yeeeaaaaheeeehh h h, , , , might have confused a few infos here.

Check this http://home.provide....on6.html#ajumbo that talks about a narrower waist than the Jumbo.

And this one http://vintage-guita...nced-jumbo.html which mentions a shallower body than the J-35 (not narrower waist). The Fabulous book speaks of the narrower waist compared to the predecessor - the Jumbo - which I thought was the Jumbo-35.

My mistake - The J-35 and the AJ both came in 1936.

 

Still not all sure of that AJ body-size he hehe, , , all though I admit you are 1 up Red 333 -

[j45nick]

Yeah, looking more closely at your measurements, your J-45's waist is almost 1/2" wider than the average of my contemporary slopes and the measurement for the AJ's waist in Gibson's fabulous Flattops, and 1/4" wider than the Collins plans indicate. That does seem like a lot. I didn't measure the width of the top at the bouts on mine, but it follows that the perimeter dimensions on yours may also be enlarged, like the waist. How did you finally solve your case conundrum?

 

Red 333

 

I finally found a new "stock" Gibson J-45(TKL) case that fit tightly, but well. Ironically, I'm actually using a custom G&G "Cali Girl" case that was made for Norman's Rare Guitars when they did a run of these a few years ago. This case was almost an impossibly tight fit at first, but the liner is gradually compressing so that it fits better and better. And it looks a lot cooler than the stock Gibson blue "cat fur" case lining.

 

The fit problem with my guitar is the slightly wider lower bout, and the wide waist.

 

I'm saving the stock case for the mythical pre-1955 SJ in pristine condition that is my own particular holy grail, and that I hope to find someday.

 

[Red 333]

 

I'm saving the stock case for the mythical pre-1955 SJ in pristine condition that is my own particular holy grail, and that I hope to find someday.

 

 

Don't worry, it's safe under someone's bed. It'll come to you in due time.

 

Red 333

[E-minor7]

Red 333 -

Pretty lit up by the issue, I managed to find a couple of shots from when I had both.

Yet I admit they don't say enough as the guitars stand slightly different on the couch.

 

Therefor my inner Sherlock tracked down the buyer of the AJ and the kind man willingly accepted to measure the body over the weekend.

What he comes up with, I don't know, but he's a precise and well educated fellow and I'm sure he'll be reliable.

 

 

. .

 

 

The waiting time will pass in utter suspense -

[P.T. Murphy]

Awesome thread! Thanks for sharing!

[Old Neil]

"Awesome thread! Thanks for sharing!"

 

Ditto that. I have flirted with the idea of an AJ on and off over time. Some things have made me hesitate though. The ones I have played felt a bit of a struggle to play compared with J-45's. Yes it might have just been the setups etc.

 

Mainly though it is just that these days my guitar budget is created by selling one guitar to buy another - and I am down to one guitar! (Standard J-45)

 

While I feel an AJ would be a great addition to any guitar arsenal I am afraid it would not be the sweet, all round song writing partner I have found in my J-45. Its sound to me seems less complex and more 'straight ahead' than a good J-45. Undoubtedly great projection for leads and clean finger picking but maybe less of an all rounder.

 

AJ owners, feel free to differ! I would love to hear what in particular about your AJ that you love over other guitars. I can at least live vicariously through you. :lol:

[GDC]

Neil:

 

I really like this AJ I bought, but I wouldn't have traded my Southern Jumbo for it for just the reasons you gave. I don't perform publicly, so volume and projection arent critical qualities for me. The AJ is great when playing with several people in those 5 rhythm guitar situations - crisp and loud. I can see why it's called a banjo killer. Even condiering those situations, though, I don't play well enough to need to be heard over others. An accomplished player would have a lot more need for an AJ than I.

 

My Southern Jumbo is more subtle and, to me, has more of the smoother, darker Gibsonesque sound I grew up loving. The AJ has it, too, but it's not the AJ's signature, if you know what I mean.

 

That's why I originally posted the question about differences in the two - well I know an SJ isn't a J-45 but it's close enough for my comparison. Mahogany seems to me to have a crisper sound than Rosewood, usually, but that doesn't hold true betweem these two guitars. So what makes the AJ bold and the Jumbo sweet?

 

My conclusion: it's Bozeman majic.

[E-minor7]

And here's some numbers -

 

 

. . . . . . . . . . . . . Length - - - - Up. bouts - - - - Waist - - Low. bouts - Up. depth - Low. depth -

 

 

2008 AJ - - - - - -51- - - - - - - - 29 - - - - - - - 26,6 - - - - 40,8 - - - - - - 9,8 - - - - - - 12,3

2010 J-45 Std. - 51- - - - - - - 29,2 - - - - - - - 27,2 - - - - 40,5 - - - - - - 10 - - - - - - 12

 

1953 J-45* - - - 51- - - - - - - - 29,7- - - - - - - - 28 - - - - - 41 - - - - - -10,2 - - - - - - 12,3

 

That's what I/we got (in cm's). We are in the detail department - mostly.

I intend to send him the result and will ask about the measure from upper body-edge to upper sound hole periphery.

If he has time they'll come by a later post.

 

*Besides the 1953 tend to be slightly conical, which makes the back wider than the top.

[JohnnyReb]

Well since the thread has turned into a casual AJ discussion I might as well jump back in

 

What do I love about my AJ over other guitars??? The fact that it's DIFFERENT! In my world of music everybody who plays back porch bluegrass and strums a Hank Williams song plays a Martin. That's fine and dandy to. However I didn't earn the nickname " JohnnyReb" by following the pack. I will admit I did for awhile but it didn't last long. Anyway back to my point, I really enjoy pulling out the AJ in front of the status quo crowd and hearing chuckles about how nobody is gonna hear a Gibson in the mix unless it's a banjo. And actually most of them don't even know what a AJ is. They assume it's a j45 and won't hold up in a bluegrass hootenanny. Much to thier surprise the AJ often is the dominate guitar in the room. That's nice for me because I always dreamed of a sunburst Gibson, but had to play Martins to achieve the volume. Not any more.

 

#2 the AJ is actually a very versatile guitar IMO. Lots and lots of headroom doesn't mean it doesn't have soft and sweet in there. I've also found that they are very sensitive to string type. Switching between PB and 80/20 makes a huge difference on my AJ, to the point I find it safe to say its almost like having 2 different guitars. A simple swap in metallics and you have a totally different animal. PB is dark and mysterious. Makes playing in minor very dreary and lonesome. Slap on the 80/20 and you got a hot flatpicking bluegrass machine that rings out like a bell and is crystal clear.

 

#3 vintage tone. Now some won't agree with this, but I feel it's true. The AJ just sounds plain vintage cool to me. If I could go back to 1936 and sit under a shade tree and listen to music, the AJ has the sound my mind would expect to hear. Loud, clear, thumpy bass, and straight to the point. In my experience this sound is best achieved with a set of 80/20 that's about 2 weeks old. Some guys ( and nothing is wrong with it) have to buy guitars that are very old to feel they have achieved a vintage tone. I feel like I have nailed it with my 2010 model and the right strings. Maybe not ENZACTLY but very close, or close enough for me. I've even had a Martin vintage series and it wasn't even close. HD28V. Had a v neck and all that good stuff, but the sound was so complex it wasn't even close to what my mind thought was vintage. Was more like a harp than a guitar IMO.

 

Anyway I could ramble all day but that's enough for now I suppose

[GDC]

"However I didn't earn the nickname " JohnnyReb" by following the pack"

 

Ha I like that!

[j45nick]

Further to the discussion of the slight variability of shapes and dimensions associated with the Gibson slope jumbo, here's a picture of the inside of the Cali Girl repro case I'm using for my J-45. At the lower edge of the side padding, just above the flat for the back of the guitar, you can see the actual imprint my old J-45 has made in the padding.

 

This case was custom-made for the nominal "stock" J-45 dimensions. You can see from the compression marks on the padding why the slightly larger dimensions of this particular J-45 made it difficult to get a case that fit properly.

 

This was a bit hard to photograph, so I hope it conveys the issue properly.

 

I suspect that today's slope J's are a lot more consistent dimensionally than the vintage ones (1948-'50) like mine.

 

[E-minor7]

 

This was a bit hard to photograph, so I hope it conveys the issue properly.

 

The photo is good - the case is better - the name is best.

Luvit. . . .

 

 

 

[E-minor7]

Additional #'s beamed in :

 

- - - - - - - Sound hole from upper body edge - - - - - S h diameter

2008 AJ - - - - - - - - - - - - 8,7 - - - - - - - - - - - - - - - - - 10

2010 J-45 - - - - - - - - - - - 8,7 - - - - - - - - - - - - - - - - - 10

1953 J-45 - - - - - - - - - - - 9,5 - - - - - - - - - - - - - - - - - 10,5

 

Not much more juice in that lemon.

I learned a little (didn't we all)

 

And how about you Boris. . . . . .

[j45nick]

Additional #'s beamed in :

 

- - - - - - - Sound hole from upper body edge - - - - - S h diameter

2008 AJ - - - - - - - - - - - - 8,7 - - - - - - - - - - - - - - - - - 10

2010 J-45 - - - - - - - - - - - 8,7 - - - - - - - - - - - - - - - - - 10

1953 J-45 - - - - - - - - - - - 9,5 - - - - - - - - - - - - - - - - - 10,5

 

Not that much more juice in that lemon.

I learned a little (didn't we all)

 

And how about you Boris. . . . . .

"Soundhole from upper body edge"? Is that measured from the forward end of the top (by the neck/body joint) back to the closest point on the soundhole, or what? If so, that would be 96.5mm on the '68 top of my old J-45, with a soundhole diameter of 100mm. Quite similar to your '53 J-45. That's with the 20-fret board on mine, which may push the soundhole down the body compared to the 19-fret board.

 

Interestingly, I think this distance is shorter on the modern J-45, which your numbers seem to reflect. Wonder what difference this makes sonically?

[Surfpick]

I had a rolling collection over a few years, including 3 Super Jumbos but no guitar had the power of my Advanced Jumbo.

 

That thing just roared.

[Joe M]

JohnnyReb thinks that 80/20's sound best on his AJ. How do the rest of you AJ owners feel? I've tried both PB's and 80/20's and am still not sure which sound "better". Any thoughts would be appreciated.