JBL 4313 Restoration
- Thread starter westend
- Start date
westend
Audiopile
The new biding posts arrived, today, so on to installation. The JBL "twist lock" binding posts that were standard for a lot of this era of JBL speakers have a couple of problems; One, were built of plastic that is annealed to a metal post, causing the plastic to either fall off or the knob to break from age. Two, could not accomodate a very big gauge of wire. Pic below is of the originals and replacements.
I purchased two different sets of binding posts, gold plated 5-ways and plastic nickel-plated 5-ways. I used the plastic, as the post is smaller and accomodates the ring terminals of the original wiring. They probably adhere more to the originals, as well. I chose to not remove the mounting board from the speaker cab because I just know there is some kind of funky sealer or glue used on the board (assumption, here) and I didn't want a frustrating bunch of torquing on the network components. I had enough clearance, inside, to change the binding posts. One pic is a shot towards the new posts and wires through the woofer hole.The other pic is a shot of the top of the network from the tweeter hole. The finished posts are shown in the pic from the back of the cabinet. There is not a lot of room to work on these through the woofer hole because the mid driver chamber is almost inline with the inside mounting locations. A 1/4" drive set with extension and wobble is your friend, in this case.
Edit: BTW, the Bennic binding posts used here were on sale at Madisound for $.90 a pair. That is not a misprint, $.90. Stock up.
I purchased two different sets of binding posts, gold plated 5-ways and plastic nickel-plated 5-ways. I used the plastic, as the post is smaller and accomodates the ring terminals of the original wiring. They probably adhere more to the originals, as well. I chose to not remove the mounting board from the speaker cab because I just know there is some kind of funky sealer or glue used on the board (assumption, here) and I didn't want a frustrating bunch of torquing on the network components. I had enough clearance, inside, to change the binding posts. One pic is a shot towards the new posts and wires through the woofer hole.The other pic is a shot of the top of the network from the tweeter hole. The finished posts are shown in the pic from the back of the cabinet. There is not a lot of room to work on these through the woofer hole because the mid driver chamber is almost inline with the inside mounting locations. A 1/4" drive set with extension and wobble is your friend, in this case.
Edit: BTW, the Bennic binding posts used here were on sale at Madisound for $.90 a pair. That is not a misprint, $.90. Stock up.
Attachments
westend
Audiopile
Onward...
Installed the drivers, L-pads, and foilcals back onto the baffle. A squirt of Deoxit Gold into the small vents of the L-pads was all I had the courage to do. They were operating fine and I didn't see any point in tempting fate. The spade connectors and speaker terminals got a squirt, as well.
I reglued the foilcals onto the baffle using contact adhesive. A small film with a flux brush and they layed down exactly flat.
Pics one and two, attached, are of the stock drivers: 066 tweets, LE5-9 mids, and LE111a woofers. I had previously replaced the surrounds on the woofers.
As soon as the grill cloth arrives, I will show that process and then, the "money" pics. The finish turned out real nice on these. It is a good grade of veneer, IMO.
Installed the drivers, L-pads, and foilcals back onto the baffle. A squirt of Deoxit Gold into the small vents of the L-pads was all I had the courage to do. They were operating fine and I didn't see any point in tempting fate. The spade connectors and speaker terminals got a squirt, as well.
I reglued the foilcals onto the baffle using contact adhesive. A small film with a flux brush and they layed down exactly flat.
Pics one and two, attached, are of the stock drivers: 066 tweets, LE5-9 mids, and LE111a woofers. I had previously replaced the surrounds on the woofers.
As soon as the grill cloth arrives, I will show that process and then, the "money" pics. The finish turned out real nice on these. It is a good grade of veneer, IMO.
Attachments
thefragger
Certified Crazy.
Lazy!? If you're lazy, then I'm being a corpse about finishing mine. Can you do them for me, even though you're lazy?
The 4313's fronts look great, where's the rest of the cab?
MAXZ28
Addicted Member
Lazy!? If you're lazy, then I'm being a corpse about finishing mine. Can you do them for me, even though you're lazy?
Sure, after I finish the gazillion projects I've got sitting in the garage. Did you see the speakers I drug home tonight? Now that's gonna be a project. :yes:
More, pics please Westend! :yes:
westend
Audiopile
I will get the wood refinishing pics up after the grills are done.
I don't know about that "lazy" thing. From your pics, it seems you are doing some of the work inside your house. Here, I have every power and hand tool you can buy (almost, always need more
), a dedicated work space, and a hardware store 1 mi. away. I'm thinking you have quite a few more challenges to finishing than I have. Irregardless, what you've done there is an inspiration to more than one of us, a really great project.Have you had any luck finding those replacements for your L-100 "craptastics"? That project will be a thing to behold.
westend
Audiopile
Started making the grill frames, today and thought I'd post up some pics of that as there aren't too many writeups about it.
I decided to use 1/2" MDF for a few reasons; easy to machine to exact tolerances, no worry or work to insure that the edges aren't chipped as you might have with plywood, easy to paint, the 1/2" BB plywood I have cost more and I have it earmarked for another project. I allowed about 1/16" - 1/8" undersizing of the frames for the thickness of the grill cloth. Final exterior dimensions were 23 5/16" X 14 1/8". The frames will have finished dimension of 1" sides, bottoms, and tops. I measured the triangular corners and layed them out with an angle square to 45`. One corner is smaller than the other three as you have to allow for the port.
For grill fasteners, I'm using small neodymium magnets. The original plastic pegs are prone to breaking and I don't like velcro because it always gets full of debris and doesn't lay flat. I drilled all holes to 5/16" which should allow enough clearance for the magnet and surrounding glue. As you can see from one of the pics, I used dowel centers to arrive at the placement of the holes in the grill frames. For those that haven't used them, they are pushed into the holes on the enclosure, you then position the panel on top of the dowel centers and give the panel a tap to make a centering hole. Slick it is.
The pic of the grill frame panels shows my layout lines for the interior cuts. One attachment shows the magnet holes drilled into the back of the grill frame. I plan on using four magnets in the enclosure and four magnets in the frame. I have heard that this might result in too much force needed to remove the grills. If that is the case, I will forgo the magnets on one piece and sustitute a metal rod or screw. No sweat.
I decided to use 1/2" MDF for a few reasons; easy to machine to exact tolerances, no worry or work to insure that the edges aren't chipped as you might have with plywood, easy to paint, the 1/2" BB plywood I have cost more and I have it earmarked for another project. I allowed about 1/16" - 1/8" undersizing of the frames for the thickness of the grill cloth. Final exterior dimensions were 23 5/16" X 14 1/8". The frames will have finished dimension of 1" sides, bottoms, and tops. I measured the triangular corners and layed them out with an angle square to 45`. One corner is smaller than the other three as you have to allow for the port.
For grill fasteners, I'm using small neodymium magnets. The original plastic pegs are prone to breaking and I don't like velcro because it always gets full of debris and doesn't lay flat. I drilled all holes to 5/16" which should allow enough clearance for the magnet and surrounding glue. As you can see from one of the pics, I used dowel centers to arrive at the placement of the holes in the grill frames. For those that haven't used them, they are pushed into the holes on the enclosure, you then position the panel on top of the dowel centers and give the panel a tap to make a centering hole. Slick it is.
The pic of the grill frame panels shows my layout lines for the interior cuts. One attachment shows the magnet holes drilled into the back of the grill frame. I plan on using four magnets in the enclosure and four magnets in the frame. I have heard that this might result in too much force needed to remove the grills. If that is the case, I will forgo the magnets on one piece and sustitute a metal rod or screw. No sweat.
Attachments
westend
Audiopile
Grill cloth install: Frames were cut out of 1/2" MDF. Holes drilled to accept magnets (or other) in the corners. Inside of frame edges were radiused with a 1/4" roundover bit, using a router. This was done to let the sound waves more easily roll out from the baffle. There is a some information about this on the web. Users can search for that and make their own determinations. It was easy to do so I did it. It probably doesn't make a whole lot of difference, IMO.
I painted the grill frames with spray primer and then hit them with a couple of coats of flat black.
Two liberal coats of contact cement were applied to the back of the frame edges and left to dry.
The cloth was positioned under the frame and then placed around the outside edges and over the dried glue. A clothes iron was used to heat the cloth and reactivate the glue to hold the cloth in place. This is a really good system as it allows for the repositioning of the cloth should it become out of line or stretched incorrectly. If the cloth is set onto one edge lightly and is then gently stretched to the opposite edge, all should be good. If a wrinkle or wave develops and the cloth has been lightly heated, it can be pulled up and repositioned and then heated back down into the glue.
The corners present the most challenge. What I did for that was to position the first edges, cut a greater angle than 45, then layed the perpindicular edge down on top of that cut angle and cut through both layers of cloth with an exacto knife. This left a corner with both edges meeting perfectly.
I trimmed the excess material with the same exacto knife and a metal rule as a guide. Pics below show most of the process and the finished product.
Magnets will be installed, shortly, and pics of the finished pair of speakers will be posted. Can't wait to get these playing again as they are really an accurate set.
I painted the grill frames with spray primer and then hit them with a couple of coats of flat black.
Two liberal coats of contact cement were applied to the back of the frame edges and left to dry.
The cloth was positioned under the frame and then placed around the outside edges and over the dried glue. A clothes iron was used to heat the cloth and reactivate the glue to hold the cloth in place. This is a really good system as it allows for the repositioning of the cloth should it become out of line or stretched incorrectly. If the cloth is set onto one edge lightly and is then gently stretched to the opposite edge, all should be good. If a wrinkle or wave develops and the cloth has been lightly heated, it can be pulled up and repositioned and then heated back down into the glue.
The corners present the most challenge. What I did for that was to position the first edges, cut a greater angle than 45, then layed the perpindicular edge down on top of that cut angle and cut through both layers of cloth with an exacto knife. This left a corner with both edges meeting perfectly.
I trimmed the excess material with the same exacto knife and a metal rule as a guide. Pics below show most of the process and the finished product.
Magnets will be installed, shortly, and pics of the finished pair of speakers will be posted. Can't wait to get these playing again as they are really an accurate set.
Attachments
westend
Audiopile
All right! They're done. Glued in the Neodymium magnets with epoxy and touch-up painted the magnet locations on the enclosure, in case anyone wants to use them with grills off. I installed magnets on the grills, as well. I polarity coded one corner of the grills and enclosures so that the corner near the port is referenced. Otherwise, the port could be slightly covered if the grills weren't oriented.
The Dark Blue cloth I got from the Zilchlab is really nice. Very close to what I remember as the factory color and weave. Thanks a bunch, Zilch.
The cabinets turned out pretty good. The walnut veneer and grain shines very sweet. There were a couple of locations that had deep scratches and rather than risk sanding through the veneer I opted to fill those with color putty and tone them with a color pencil. They are noticable but these are "living room ready", IMO. Since these were used in a mixing room, it looks like they were layed on their sides, as the tops were, basically, scratch-free.
For the time and expense, I think speaker restoration is an easy and worthwhile project. I'm lucky to have these 4313's to use for that kind of a project.
The Dark Blue cloth I got from the Zilchlab is really nice. Very close to what I remember as the factory color and weave. Thanks a bunch, Zilch.
The cabinets turned out pretty good. The walnut veneer and grain shines very sweet. There were a couple of locations that had deep scratches and rather than risk sanding through the veneer I opted to fill those with color putty and tone them with a color pencil. They are noticable but these are "living room ready", IMO. Since these were used in a mixing room, it looks like they were layed on their sides, as the tops were, basically, scratch-free.
For the time and expense, I think speaker restoration is an easy and worthwhile project. I'm lucky to have these 4313's to use for that kind of a project.
Attachments
specialidiot
Break Glass, Smoke Lucky
Well done Lance! Don't forget to play Alice's Restaurant on them today!
PioneerKing
New Member
Very sweet! Great job.
Fred Sanford
Addicted Member
Nice work, and thanks for the efforts in the documentation of the process.
:thmbsp:
je
:thmbsp:
je