JBL History: When was the switch from plywood to MDF/particle board for cabinets?

[Nordschleife]

Does anyone know when JBL first started using particle board construction on its factory cabinets?

Is it possible that some of the longest-running designs, like the C-36, C-38, and C-40 used particle board rather than plywood around 1963-64 or even later?

I found this post but it didn't answer the question, unfortunately: http://www.audioheritage.org/vbulletin/showthread.php?7543-Particle-Board

Thanks, Andy

[BMWCCA]

Is it possible that some of the longest-running designs, like the C-36, C-38, and C-40 used particle board rather than plywood around 1963-64 or even later?

Not that it will help with the dates, but: I have a C37 cabinet I bought used but factory-loaded with the 030 system. I bought it sometime around 1968. It's made of MDF. I have a pair of C35s I bought empty from someone out west and had shipped to Virginia over a decade ago. One is MDF and the other is plywood. All are in storage currently or I could check the driver serial numbers in the C37 and maybe that would date the MDF for that model. The C35s might not hold any clues to help determine their date of manufacture. :dont-know:

[Mr. Widget]

Not that it will help with the dates, but: I have a C37 cabinet I bought used but factory-loaded with the 030 system. I bought it sometime around 1968. It's made of MDF.Are you sure that it is MDF and not particle board? I always thought that MDF didn't become widely used in furniture and cabinet making until the mid to late '70s. I know my early to mid '70s L100s are made of particle board.


Widget

[BMWCCA]

Are you sure that it is MDF and not particle board? I always thought that MDF didn't become widely used in furniture and cabinet making until the mid to late '70s. I know my early to mid '70s L100s are made of particle board.
You're probably right since a quick Google search shows that large-scale manufacturing of MDF wasn't begun until the '80s. As i recall the material looks to be somewhat more chunky than just sawdust but it's been quite some time since I've examined them.

[Nordschleife]

I'm wondering if the arrival of the JBL Energizer amplification option (1963?) correlates roughly with the first particle board JBL cabinetry?

I haven't seen a plywood-based cabinet with the back panel cut-out for an Energizer... only the particle board. But I have limited knowledge and experience in this. Has any Forum Member seen a plywood cabinet with cut-outs for the Energizer amplifier?

Other running changes would seem to include the simplified late 1960's JBL insignia grill badges + the crossover's rear panel cut-outs moving from the side to the center.

Again, I'm a newbie at this. I'm hoping some more seasoned members will chime in so I can learn.

Best, Andy

[Horn Fanatic]

You're probably right since a quick Google search shows that large-scale manufacturing of MDF wasn't begun until the '80s. As i recall the material looks to be somewhat more chunky than just sawdust but it's been quite some time since I've examined them.

Greetings -

I have the 1958 Harkness, 1959 Hartsfield and Paragon, and the 1960 Metregon drawing packages. The panel material specified for the Harkness was plywood. For the Hartsfield, JBL specified a material called, "Timblend". A fancy name for total crap for something slightly better than floor underlayment. The drawings for some of the panels used on the Paragon and Metregon specified particle board, most likely the same material. Yes, the material did have a chunky quality to it. It's a shame the material was used, because under the wrong conditions it did not withstand the test of time.

You're right, American manufacturers began using MDF in large scale production in the 80's, however, it was developed in the U.S. in the early 60's. The early models C36 and C38 were made of plywood.

It may be a safe bet that JBL began phasing out plywood by the late fifties. I have repaired several C36 and C38 enclosures made of particle board. Some models having the Energizer blank panel, which would indicate the earliest manufacturing date to be 1964.

I use MDF extensively in the construction of my enclosures. One feature that I like about it, is it's consistent thickness. Whether it be Ranger Board manufactured in Canada, or Aries Board manufactured in Oregon, the thickness, without deviation throughout the panel, is 25/32 inch thick.

H.F.

[jblsound]

The 1977 L212 was particle board boxes. The wrap-around grille cage was 3/8" plywood.
I don't think MDF was used until the '80s.