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Portaflex dimensions / construction

#24
well, i guess i shouldn't complain about patents only going 20 years. i guess it would hold up overall progress in the world to have them go much longer.

sorry, just thinking out loud and upping my post count for no good reason.
 
#25
The overall dimensions of the cabinet, and the general construction details are pretty well laid out in the earlier thread. Missing are detailed dimensions for the top and baffles. I can't help with the top, but since you have an amp already, you may be able to fill in those blanks yourself.

That leaves the baffles, which are the most interesting feature of this cabinet. Here's what I come up with for the speaker and grill baffles, derived from photos and text. Vent and screw hole locations are photo-estimated; should be non-critical. One dimension that disagrees with Vintage-Blue's description is the width of the bar on the grill baffle. Text says 7/8, but it was thicker in the photos.

speaker baffle - 3/4" plywood:
[Invalid or Expired Link Removed]

grill baffle - 1/2" plywood:
[Invalid or Expired Link Removed]

Corrections/additions welcome. BTW, anyone know the tuning of this thing?
 
#26
For reference, here is the Link Removed I work off of. Although I use 8 speaker mounting screws this drawing just shows the 4 that were used on the originals.

The discrepency in the grille baffle crossbar width is due to me originally getting my dimension from a single baffle cabinet, which is wider. The bar on the double baffle grille baffle is about 7/8".
 
#27
Wow! This thread just turned amazing.

So one area that I find a little confusing it the construction of the top of the cab; like how the top pieces fit to make the opening and marry with the sides and front and how the lip for the lid is made. And can we get some measurements on the chamfered handles.

Also, would poplar be cool for the front frame?
 
#28
You don't want Mark to give away all his secrets do you? ;)

Here are a set of pics that should answer your questions. The side handles are 2" vertically, 5 1/2" horizontally. The one with the ruler is the money shot. You should be able to infer all the other dimensions. Yes poplar is an excellent choice for the face frame.

Top construction detail
[Invalid or Expired Link Removed]

Top corner back
[Invalid or Expired Link Removed]

Top corner front
[Invalid or Expired Link Removed]

Ruler top side
[Invalid or Expired Link Removed]

Top frame
[Invalid or Expired Link Removed]

Side top detail
[Invalid or Expired Link Removed]

Side top front 2 3/16" wide top strip
[Invalid or Expired Link Removed]

Side top back 3/4" wide top strip
[Invalid or Expired Link Removed]
 
#29
One quick question... how is the lip attached to the top back strip? I see the miter in the corner which implies it's floating but I assume goes all the way to the back of the cab?

BTW: I thank Mark for sharing his info. I know this is a business for him and I don't expect him to share any of his "secrets" that he's made into his improvements on the original... I just want to get the details for the original and go from there.

I don't expect to make more than one of these unless I find another orphaned head ;)
 
#30
Here are some photos that may help:

16.jpg



22.jpg



26.jpg



04.jpg


The hand holds are cut using an 8" dado blade and a fence mounted perpendicular to the blade.
 
#31
Tronographic said:
I thank Mark for sharing his info. I know this is a business for him...
Click to expand...

Agreed; very generous of him. Now that he has posted his own baffle drawing, my exercise looks a little silly. I thought he probably had drawings, but made my own because this is his business... seemed too presumptuous to ask for his. Looks like I was within 1/16th on hole locations, but I will revise my drawings to match.

The pictures of the top construction (thanks beans-on-toast and Vintage-Blue) seem to complete the picture. Tronographic, you've got your work cut out for you. This is not your ordinary cab build.

Judging from the photos here, I'd say Vintage-Blue's product is superior to the original. I doubt there will be many who would elect to build when you can buy something that good.

Still interested in any info about the tuning/response of this cabinet.
 
#32
I've never seen anything published on the response of the double baffle cab. Jess designed it by the seat of his pants and it was one of those rare and amazing outcomes. He probably started with a basic idea and tuned it by ear.

It would be interesting to see the results if it were modelled.


David
 
#33
I forgot to mention something when I posted those photos. The pieces that form the front and rear of the opening in the top of the cabinet (I call them the upper front rail and upper rear rail) need to be about 13/16" thick. This helps keep the lid flush after taking into account the thickness of the Tolex. Otherwise the lid will sit up a little. Also, the edges of the cabinet get rounded over with a 1/4" radius roundover bit. That's a little tighter than what you usually see on a cabinet but it's necessary because the lid gets radiused on the top and bottom edge. That only leaves about 1/4" flat surface to mount any sort of latch catch on.
 
#34
beans-on-toast said:
I've never seen anything published on the response of the double baffle cab. Jess designed it by the seat of his pants and it was one of those rare and amazing outcomes. He probably started with a basic idea and tuned it by ear.

It would be interesting to see the results if it were modelled.


David
Click to expand...

This is the only info I ever got from Jess regarding the tuning, and it isn't much:

"Anyway, I carefully tuned the enclosure using a speaker with a resonance of 50 cycles, to smooth out the typical hump in the low frequency response."
 
#35
1n3 said:
Judging from the photos here, I'd say Vintage-Blue's product is superior to the original. I doubt there will be many who would elect to build when you can buy something that good.
Click to expand...
i can go through the ways that you would, indeed, be right. jess had everett hull looking for ways to cut costs, and often second guessed the design. for example, when i opened my 64 up for the first time after 7 years of owning it, i discovered hard foam pieces stuck in the baffle slots to block them! i pulled them out and the cab opened up. jess said everett hull did that because he was hard of hearing and didn't know it.

one touch i really like is mark's baffle slots. the old ones were flush with the cab's inner walls, and if tolex ever got loose, it would rattle loudly. moving the baffle slots into the baffle a little more doesn't change the sound at all but it keeps loosened tolex from rattling. the big thing for me was out of all the b-15 cabs i ever had, mark's was the only one where i wasn't constantly chasing rattles for the first week. rattle-free out of the box.

but i'm down with home builds (trono's not exactly a home build but you know what i mean) and would dig seeing the finished product. mark is the man for these cabs, so you do what he says and you won't go wrong.
 

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