dumble speaker cabinet

[Funkalicousgroove]

Funkalicousgroove wrote:

the dumble cabs are made from regular plywood or pine and have butt joints!!

They sound like the perfect candidates for anyone that wants to make fakes. No special tools to buy for finger jointing and no particularly refined woodworking skills needed.

Funk, do the originals have any badges or logos anywhere on them to distinguish/ identify them from any other cab out there that may have the same dimensions? Robben's doesn't!


My advice would have to be, save $7500 and have one made as a homage to the big guy (Obviously don't then try to sell it as an original, besides you don't want to tread on MG's toes. )


From what I hear, the top end of the vintage/ collectables market has taken the biggest hit in the recent economic climate, so 8K for a cab wouldn't be where i was putting my money at the moment.

A friend of mine has a tan 4x12 that used to belong to RF, and there are no marks on it, nor were there any on LC's 1x12. I stuck my head inside of robbens when I had the opportunity(the very one in that pic) and didn't see any distinguishing marks.

Here's another funny one, he likes to use those black zinc deck screws to hold the back on, same with the head cabs. LC's black head cab has the back held on with 3 screws! talk about frugal!

[Max]

Deleted Post

Hi all,

sorry, but Omar asked me to delete the post with the quote of the Steven Rosen interview. He was asked to do so by Jesse Schwarz, the author of "A Dumblebook". As Jesse says, he owns the copyright and sees my post as a violation of this copyright.

Sorry Jesse, sorry all others here, I've meant no harm to none of you.

Max

[Guitarman18]

Max wrote:

The trick is.. as I said, that you select pieces so that theirs no hollow spots, nothing leaks....

Does he mean avoid using pieces with knots in?

Thanks Max for the info.

Cheers,

Paul.

[Max]

Max wrote:

The trick is.. as I said, that you select pieces so that theirs no hollow spots, nothing leaks....

Does he mean avoid using pieces with knots in?

Thanks Max for the info.

Cheers,

Paul.

Hi Paul,

I think he refers to the holes that you often find in industrial lumber woods where a branch of the tree was before the cut.

I once had the opportunity to inspect the hole in a 4 x 12 cabinet that was cut to receive the handle and I can confirm that I did find precisely the wood structure (lumber wood with a veneer on both sides) that Mr. Dumble is talking of. The mahogany was a very lightweight one (otherwise a 4 x 12 with 4 EVM 12 L would be a "heavy" problem).

Have a nice sunday

Max

[Funkalicousgroove]

The 4x12 i know personally is made of plywood(looks like about 5 ply DIY grade to me), and is QUITE heavy. the grain pattern on the outer veneer is definitely not mahogany, LC's 1x12 cab sounded like it was made of pine when I knocked on it, may have been redwood, but sounded pretty identical to one of my 1x12 birch cabinets( I just sent him one, we'll see if he agrees ).

Spruce plywood, like basswood plywood, I believe is intended for building model boats and airplanes, and lacks the strength(certainly with butt joints) that I would want to see for an amp intended to be out on the road.

I also know that The original Mojotone company (when they were in california) produced alot of cabinets for Dumble, their choices are birch ply and pine.

The 2x12 open cabs sound overly wooly and undefined in pine or poplar, "lumber core" isn't readily available as it was in the 70's and 80's due to it's cost and declining popularity, and is typically basswood ply with an applied veneer for asthetics. Unless it it precicely made it can have voids that run the entire length of the board, it is no more "real wood" than any other plywood, but is designed for decoration, not for this type of cabinet building, and certainly not for strength. The high density baltic birch ply that is an industry standard for non-resonant speaker cabinets is a far superior choice, it is stronger, easier to mill, makes cleaner routed edges, and is truly voidless.

[muchxs]

Where were you guys last year?

A local cabinet shop (kitchen cabinets) moved to a new location and left a large stack, around a full lift, of vintage lumber core plywood in their old warehouse. I split the material with a neighbor. I made some low cost cabinets with it. Lumber core was a hard sell, "everyeone" wanted birch ply...

I have a tiny bit left, maybe enough to make one more cabinet. My neighbor has four full sheets left.

My personal experience with the material: It's luan which is a cheap lightweight species of mahogany. The core is assembled from little 5/8" pieces thick of wood butt jointed together. The manufacturer didn't waste any time assembling the core, saw through a butt joint in the core and often as not it would have a void. Cut the panel close to a butt joint in the core... there's no way to tell where the joints in the core are... and a chunk would blow out when I did the roundover.

The core seems to be made up of strips around 1" wide. I could strip the face veneer in the planer and find out how long the core strips are. I'd expect less than a foot long each, maximum.

Tone-wise lumber core is less articulate than solid wood regardless of species in "identical" cabinets. I say "identical" because joinery appropriate for solid wood is inappropriate for lumber core. In terms of resonance the material is relatively "dead", vibration can't propagate because the butt joints in the core damp vibration.

I can make my own lumber core plywood for the next month to six weeks, after that we're going to divest of our veneering equipment.

[Funkalicousgroove]

I really think that stuff is an AWFUL choice for cabinet building. If weight is an issue Poplar or basswood(another BAD choice) ply is much lighter than birch, Poplar is also brighter sounding.

[muchxs]

I really think that stuff is an AWFUL choice for cabinet building. If weight is an issue Poplar or basswood (another BAD choice) ply is much lighter than birch, Poplar is also brighter sounding.

I don't know if there's any such thing as a "bad" choice. It's a matter of taking inventory of the assets and liabilities of each material and building accordingly. I use a wide variety of materials in my cabinets each according to its application. I may from time to time mention what I use and where but I'm not going to belabor the point. I run headlong into blanket statements that some materials and methods are great and others are useless.

Case in point: Steve Vai's Carvin Legacy cabs. Poplar ply and loaded with Vintage 30s. The Legacy has a presence control that accentuates frequencies above 10khz. The Vintage 30s are relatively shrill, 10khz is an octave above where they start rolling off. On paper it seems bizarre but it apparently works.

I could take the comment that "pine sounds wooly and undefined" out of context and extrapolate to say that pine sounds wooly and undefined, period. It's a matter of taking the properties of the material into consideration, considering the application of the final product and building accordingly. I never get comments that my pine cabinets sound "wooly and undefined", quite the opposite.

[ampcrack]

("Yeah, I like using real wood. You can’t get me to look at a piece of particle board, I hate particle wood.
I hate other kinds of woods... birches is been ran down my throat, but I hate birch plywood, I think it’s the worst thing in the world to use for building equipment. It’s just you avoid it at all cost. It just doesn’t work, you might as well use particle board for that, instead of birches. )

Take 2:

Hi Max,

I'm John, and I'm still trying to find out where you got the comment by Mr.D from? Is there more?
Give us a link.

John

[muchxs]

Comments from Dumble notwithstanding, I believe we've effectively eliminated most cabinet materials

Attributed to Dumble: "Yeah, I like using real wood. You can’t get me to look at a piece of particle board, I hate particle wood.
I hate other kinds of woods... birches is been ran down my throat, but I hate birch plywood, I think it’s the worst thing in the world to use for building equipment. It’s just you avoid it at all cost. It just doesn’t work, you might as well use particle board for that, instead of birches. )

So cross off particle board and Baltic birch.

The 4x12 i know personally is made of plywood(looks like about 5 ply DIY grade to me), and is QUITE heavy. the grain pattern on the outer veneer is definitely not mahogany, LC's 1x12 cab sounded like it was made of pine when I knocked on it, may have been redwood, but sounded pretty identical to one of my 1x12 birch cabinets( I just sent him one, we'll see if he agrees.

But we've already eliminated birch ply as a non-HAD approved choice.

Spruce plywood, like basswood plywood, I believe is intended for building model boats and airplanes, and lacks the strength(certainly with butt joints) that I would want to see for an amp intended to be out on the road.

So we can eliminate spruce plywood and basswood plywood. Genuine spruce plywood is rare and expensive, it's used in experimental aircraft. Those are full sized aircraft not models. It's marine grade plywood. IMO it would be an excellent material if not for its cost.

I also know that The original Mojotone company (when they were in california) produced alot of cabinets for Dumble, their choices are birch ply and pine.

But we've already eliminated pine because it sounds "wooly and undefined". We've eliminated birch ply because it's not Dumble approved.

We've deduced that mahogany lumber core is the HAD approved material but not basswood core or poplar core. IMO the poplar core is superior to luan core especially in U.S. manufactured furniture grades.

We then eliminated lumber core because it's not Brandon approved.

By process of elimination we're left with MDF.

It's the only material not mentioned in negative terms.

[Max]

("Yeah, I like using real wood. You can’t get me to look at a piece of particle board, I hate particle wood.
I hate other kinds of woods... birches is been ran down my throat, but I hate birch plywood, I think it’s the worst thing in the world to use for building equipment. It’s just you avoid it at all cost. It just doesn’t work, you might as well use particle board for that, instead of birches. )

Take 2:

Hi Max,

I'm John, and I'm still trying to find out where you got the comment by Mr.D from? Is there more?
Give us a link.

John

Hi ampcrack,

This statement of Alexander concerning the timbers he uses is taken from an interview he once gave to journalist Steven Rosen. A friend of mine once sent me this part of the interview because we talked about Alexanders construction principles in regard of his cabinets. As far as I know this interview was published in a european musicians magazine in the late eighties. Perhaps someone here has a copy to post?

On Bill Morgans site you find a chapter called "Dumble gallery by Atelier der Tonkunst" There you find a picture of Mr. Dumble working on the "Pentode Dumbleland". This picture was published together with this Steven Rosen interview.

My current understanding is, that Steven Rosen still offers copies of the original tapes (and pictures) of all his countless interviews including this one with Alexander Dumble. Try your luck with a Google research. Maybe you can still buy a tape of this interview from Steven Rosen. Some years ago there was an offer in the bay too. Perhaps someone else knows more.

Have a fine sunday and all the best

Max

[Bob-I]

I never get comments that my pine cabinets sound "wooly and undefined", quite the opposite.

I agree. The best sounding amp I had in the 60's-70's was an original 5F6-A bassman I bought for $50 after a puppy scratched out the speakers. The replacement Jensen's cost me $8 each.

That pine cabinet sometimes felt like it was shaking itself apart but always sounded great.

One night in 1977 our soundman decided to carry it down a fire escape holding it by the original leather strap outside of the railing. He was 2 stories up when the handle let go. We only picked it up so we wouldn't be fined for littering.

I built a new cabient out of ply but it never sounded the same. I sold it about a year later for $800.

Now years later I'm convinced that the tone was in the pine cabinet.

[butwhatif]

The tone 'is' the pine cabinet. From my 40+ years of playing experience, it is
harder to get the warm lows out of hardboard and hardwood cabinets. The lows go thru a pine cab. It vibrates like crazy, and this produces a wider, warmer sound. If you're building a studio monitor, it ain't going to work, but in a guitar cab it does.

[muchxs]

The tone 'is' the pine cabinet. From my 40+ years of playing experience, it is
harder to get the warm lows out of hardboard and hardwood cabinets. The lows go thru a pine cab. It vibrates like crazy, and this produces a wider, warmer sound.

And there you have it.

One camp says, "Build it as dead as possible." A cab like that is supposed to "let go of the note" which is fine I guess if you're building Urei replicas. The drawback to a "dead" cabinet is that it's dead, it's not lively.

A "wooly" sounding cabinet is the other extreme. Very lively. some would say too lively. If that resonance is there to begin with it can be tuned, if it's not there to begin with it's simply not there.

[butwhatif]

Try it sometime-- I've built cabinets out of oak, bubinga, yellow birch, pine, plywood. The hard wood cabs always gave a tight focused sound. They never made me happy, although they looked like a $mil. Fender amp cabs didn't do this, and I've copied a few of them with hardwood, especially combos. They never sounded as good as pine. If you want lively, use pine, if you want focused, use the other stuff.