Old 2x15 Bass Cab to Guitar Cab

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David Root
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Joined: Fri Aug 04, 2006 3:00 pm
Location: Chilliwack BC

Old 2x15 Bass Cab to Guitar Cab

Post by David Root »

I have this old closed back ported bass cab with a pair of JBL D140Fs, see pic. I would like to convert it to an open back 2x15 guitar cab with a pair of Altec 418Bs (if I can find them).

Anyone have oval back opening dimensions for this size cab? Or an intelligent guess?

The port BTW is a rectangular opening to the left covered by the small piece of fiberglass insulation.

Should I keep it or plug it? Or change it to round? Or what?
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jaysg
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Location: Sandy Eggo

Re: Old 2x15 Bass Cab to Guitar Cab

Post by jaysg »

Are the JBLs bass speakers?

Create a small panel to close the vent, then experiment with it later on.

If I was going down the oval path, I would start with a cheap piece of plywood, cut with the Dumble 2-12" size oval. Expand the oval bit by bit and see what you think. You'll know when you've gone too far, then do it up right.
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David Root
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Joined: Fri Aug 04, 2006 3:00 pm
Location: Chilliwack BC

Re: Old 2x15 Bass Cab to Guitar Cab

Post by David Root »

Thanx jaysg, I think D140Fs were bass speakers, they certainly sound like it. (Edit, they are bass speakers, from about 1967 is the earliest JBL catalog I could find).

I am looking for a Dumble oval as it would be used with D-clones, but I posted here as it is I think of general interest.

BTW I didn't show a pic of the front but the bottom several inches of the grille cloth is caked with dry cat piss. Any "Wonder Cures" to get rid of that, short of re-grilling?
toneslinger
Posts: 48
Joined: Tue Feb 16, 2010 3:15 am

Re: Old 2x15 Bass Cab to Guitar Cab

Post by toneslinger »

David Root wrote:Thanx jaysg, I think D140Fs were bass speakers, they certainly sound like it. (Edit, they are bass speakers, from about 1967 is the earliest JBL catalog I could find).

I am looking for a Dumble oval as it would be used with D-clones, but I posted here as it is I think of general interest.

BTW I didn't show a pic of the front but the bottom several inches of the grille cloth is caked with dry cat piss. Any "Wonder Cures" to get rid of that, short of re-grilling?

Id do this if you can get grill and baffle off.
have a new one made.
keep old one just as is on the baffle and all...

But take THAT to dry cleaners and have them
steam clean that cat pee out.

You could try that first without having one made
but in case it just does not break loose and the stain lifts out,
you would be good to go anyway.

I used 91% alcohol on pinstripe grill and used a clean cloth
and wiped straight in downward motions till i got to bottom of cab.

The cab looked fantastic after I was done But if this is fender
grill steam cleaning will work me thinks.

you can walk that into cleaners and they have steamers
that might get that done right out front sometimes.

The might want the cloth free of baffle though
if that does not come out...

you might try steam cleaner you can rent too..
I just think cleaners would be best.

Good luck.
toneslinger
Posts: 48
Joined: Tue Feb 16, 2010 3:15 am

Re: Old 2x15 Bass Cab to Guitar Cab

Post by toneslinger »

toneslinger wrote:
David Root wrote:Thanx jaysg, I think D140Fs were bass speakers, they certainly sound like it. (Edit, they are bass speakers, from about 1967 is the earliest JBL catalog I could find).

I am looking for a Dumble oval as it would be used with D-clones, but I posted here as it is I think of general interest.

BTW I didn't show a pic of the front but the bottom several inches of the grille cloth is caked with dry cat piss. Any "Wonder Cures" to get rid of that, short of re-grilling?

Id do this if you can get grill and baffle off.
have a new one made.
keep old one just as is on the baffle and all...

But take THAT to dry cleaners and have them
steam clean that cat pee out.

You could try that first without having one made
but in case it just does not break loose and the stain lifts out,
you would be good to go anyway.

I used 91% alcohol on pinstripe grill and used a clean cloth
and wiped straight in downward motions till i got to bottom of cab.

The cab looked fantastic after I was done But if this is fender
grill steam cleaning will work me thinks.

you can walk that into cleaners and they have steamers
that might get that done right out front sometimes.

The might want the cloth free of baffle though
if that does not come out...

you might try steam cleaner you can rent too..
I just think cleaners would be best.

Good luck.
ps if the feline spray does not come out of your cab
but kind of comes cleaner, you might think of using
coffee grinds in cloth and or light tea stain and misting
the entire grill a tad darker towards the cat pee color.

I have some marshall pa cabs that have some odd spots
in center mis-colored lighter so im tempted to
mix up some tea and slowly paint that in from outer edge to center
to match back the lighter areas....
working from outer edge in small areas inward you can blend to eye
and do a little then let dry and see if it blends.

Then do more till you blend... if the entire thing is nearly clean but
only bottom area is cat pee vintage then you might try matching first
then working from clean edge to stained.

It might work and look vintage all over and the same cat pee vintage color.

But overall it would look warmer. and more period cat pee vintage correct
might blend better also it might stain in and not fester that
vintage stench along with your project.

meow
toneslinger
Posts: 48
Joined: Tue Feb 16, 2010 3:15 am

Re: Old 2x15 Bass Cab to Guitar Cab

Post by toneslinger »

David Root wrote:Thanx jaysg, I think D140Fs were bass speakers, they certainly sound like it. (Edit, they are bass speakers, from about 1967 is the earliest JBL catalog I could find).

I am looking for a Dumble oval as it would be used with D-clones, but I posted here as it is I think of general interest.

BTW I didn't show a pic of the front but the bottom several inches of the grille cloth is caked with dry cat piss. Any "Wonder Cures" to get rid of that, short of re-grilling?

Id do this if you can get grill and baffle off.
have a new one made.
keep old one just as is on the baffle and all...

But take THAT to dry cleaners and have them
steam clean that cat pee out.

You could try that first without having one made
but in case it just does not break loose and the stain lifts out,
you would be good to go anyway.

I used 91% alcohol on pinstripe grill and used a clean cloth
and wiped straight in downward motions till i got to bottom of cab.

The cab looked fantastic after I was done But if this is fender
grill steam cleaning will work me thinks.

you can walk that into cleaners and they have steamers
that might get that done right out front sometimes.

The might want the cloth free of baffle though
if that does not come out...

you might try steam cleaner you can rent too..
I just think cleaners would be best.

Good luck.
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David Root
Posts: 3540
Joined: Fri Aug 04, 2006 3:00 pm
Location: Chilliwack BC

Re: Old 2x15 Bass Cab to Guitar Cab

Post by David Root »

Thanx toneslinger, I'll take a look at getting the baffle out. It is "vintage" cat pee because that little kitty went to the happy hunting grounds some years ago.

On the oval size, would the area of the oval vary as the volume of the cabinet? Or the area of the front baffle? I am not well versed in speaker enclosure theory, although I have heard that HAD just cut holes in the back until it sounded right. Is that true?
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