L300 glass - what goes under?

[remusr]

The surface under the glass on my new-to-me L300's is rough and chipped black paint - what was there originally? I recall something about black felt?
*I could just put a special picture there I guess....
- Roy

[Regis]

The original under-glass mat was actually a two-sided felt cardboard piece. One side was black and the other was brown. That way you could flip it depending on grill color. I used a black rubberized felt pad on top of black cardboard to get the height right (even with the edges on the side). You can find this pad material at an art supply store, but it wasn't big enough to do the whole top. I had to use two pieces laid side-by-side and taped from underneath. Underneath the smoked glass, you can't really tell there's a seam there and this will do until I find a similiar material in a larger size.

[Audiobeer]

Yo can have matting cut at the portait shop as Regis suggested at the exact size. The felt I found was identical to original but the back side was white. I had to color the edge. It was the exact fit and hieght. Unfortunately it was about $55.

[John W]

I needed something similar for my L65s. I used some 1/16 in black craft foam from the local craft store. It provided enough room for the JBL emblem and looked identical under the glass.

Here is a link to a whole packet of different colors for $4.95.
http://www.sciplus.com/singleItem.cfm?terms=11912&cartLogFrom=Search%20%2D%20Category%20Filter

[majick47]

My L300 speakers felt cloth under the smoked plate glass had long ago disintergrated. The felt cloth had been glued to a thin, maybe 1/8", piece of plywood. The plywood on one speaker had lifted from the top of the speaker and also may of been cut short at the factory. I purchased to large black foam poster boards from a "crafts" store and cut them to size. Under the smoked glass it is almost impossible to tell that it isn't the original black felt. I plan on locating some thin plywood and covering it with black felt like the original from the factory. I also used some "etched glass" JBL decals attached to the underside of the plate glass. My question is what was the original JBL logo under the plate glass? I'm guessing it might of been JBL grill badges without the pin on the back.

[vettedrummer]

L300's didn't have the JBL logo under the glass. On the L300 the logo is located on the grille cloth on the lower corner. Cheers

[edgewound]

The original material under the L300 and L65 glass was a thin foam sheet laminated to poster board....that's why it deteriorates, just like foam surrounds. If it was cloth felt, it would not rot like that.

[dave]

I discovered that 3mm Darice craft foam is almost a perfect fit (in terms of final glass height) for the L65 under-glass mat. It is made of black Ethylene Vinyl Acetate ("EVA") and Low-Density Polyethylene. NOT exactly the same as the L65A manual quotes (the JBL manual says they used polyester foam).

Dimensions are as follows: depth of L65 top well = 0.350"; smoked glass thickness = 0.225"; ideal mat thickness = 0.350 - 0.225 = 0.125".

The 3mm Darice craft foam has equivalent thickness of .118" (uncompressed) - very close to the 0.125" needed. It comes in black and other colors, in 12" x 18" sheets, for $1.49 per sheet. The Darice part number is 1184-51 & it is obtainable from Michael's Crafts, etc. The Darice web site is www. darice.com. I cut my mats to 12" x 16.75" using a paper-cutter.

Now, I just need to find out how to replace the JBL emblem/logo. Any ideas on this?

Regards.:)

[57BELAIRE]

The original material under the L300 and L65 glass was a thin foam sheet laminated to poster board....that's why it deteriorates, just like foam surrounds. If it was cloth felt, it would not rot like that.

Here is a pic of the original piece (or what's left of it) found
under the glass on a 300.

One side was brown foam the other side black and as you can see the foam has melted away just like EVERY piece of foam JBL has ever installed in their offerings. :banghead:.

A nice piece of 1/4 inch black felt cut to size should do the trick ;)

[Zilch]

I believe someone earlier determined that black picture matting from the framing shop was a good match.... :yes:

[yellowshark]

L300's didn't have the JBL logo under the glass. On the L300 the logo is located on the grille cloth on the lower corner. Cheers


can anyone tell me the EXACT position of this logo on the grille? Meaning: how many mm down to the front edge of the grille and how many mm to the right hand side front edge of the grille. (I also reluctantly accept inches). Thanks!

[Beowulf57]

can anyone tell me the EXACT position of this logo on the grille? Meaning: how many mm down to the front edge of the grille and how many mm to the right hand side front edge of the grille. (I also reluctantly accept inches). Thanks!

I don't have a measurement...but how about eyeballing it:

:007:

[yellowshark]

I don't have a measurement...but how about eyeballing it:

:007:

My perverse perfectionism keeps me from eyeballing...

Thanks anyway! If I don't get the exact data I will have no alternative but to eyeball

[Doc Mark]

Hello, Yellowshark,

Well, I just measured my own L300's, and unfortuately, they don't measure the same! So, here is the measurement for one of them. Since both have original JBL grills, and they do not measure the same, I think that if JBL "fudged" this a little, then you can, too. (IF your perfectionism will allow it!) ;):D;)

Measuring from the right side of the grill frame, to the right edge of the JBL logo plate = 38.99mm

Measuring from the bottom of the grill frame, to the bottom edge of the JBL logo plate = 43.48mm

I hope that helps you. Good luck, have fun with your fine L300's, and God Bless!

Every Good Wish,
Doc

[midlife]

When I had my 300s, I was considering have a thin layer of granite or marble taking the place of the glass. Never got around to it though.

[pierce]

Measuring from the right side of the grill frame, to the right edge of the JBL logo plate = 38.99mm

Measuring from the bottom of the grill frame, to the bottom edge of the JBL logo plate = 43.48mm


.01mm ?!? thats 4/10,000ths of an inch :blink: my friend with his CNC milling machine can barely cut steel to that precision.

how about... 39mm and 43.5mm, k?

I bet those were placed by hand in the factory, and +/- 1-2 mm is plenty close enough for jazz OR government work. looking at that picture, and another in the '79 home catalog, I'd say 1.5 logo widths from the right edge and 1.5 logo widths from the bottom edge ...

[4313B]

My perverse perfectionism keeps me from eyeballing...

Thanks anyway! If I don't get the exact data I will have no alternative but to eyeballPerfectionism or literalism?

Tolerances are a fact of life... I know it sucks but that's just the way it rolls...

[pierce]

ok, make an L out of cardboard that's just the spacing you want, and use that as a template to place them, so they are both the same. that's probably just about what they did in the factory...

[pierce]

I found another picture ofa l300 from the other angle, over in the literature postings ...

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=37677&stc=1&d=1235940884


I measure the grill as 341 pixels horizontally (yes, its slanted, but this all scales, trust me (muahahaha). spec says its 23" wide, so thats .067" per pixel. the right edge of the badge is 23 pixels from the right edge of the grill, so thats 1.55" or 39.4mm

vertically, the bottom edge of the badge is 28 pixels from the bottom edge of the grill, or 1.88" or 47.65mm.

for cross checking, I'm 'measuring' the badge as 1.24" wide by 0.95" high, at the outside of the chrome border. is that close to reality or am I scaling this way off?

note, the badge in THIS picture looks significantly higher than the badge in the other cover, where the speaker is tilted the other way. personally, I'd think it would look 'better' a touch lower than in the above cover picture...

[John]

You know I think that darn badge would look just as good if not better in the top right corner. :banghead:

I know JBL got quite a few things right but there were plenty of bloopers over the last 60 years. :bouncy:

Does anybody use there JBL,s for listening anymore or just to go :nutz:

[yellowshark]

Thanks to helpers and jokers for determining the position of the "darn" badges.

If you click the link below you can see what the L300 looked like when I found them: some moron had painted the entire cabinetts black. The grilles were gone except for one little piece of the inner board and -luckily! - two of the corner pieces. Only with the help of these two pieces I was able to determine the angles right and reconstruct the grilles. Of course I got some help from pictures and folks from this forum - thanks again!

The woofers are still out for refoaming, the L91/2308 are on their way to me from Japan. All other drivers are perfect. The smoked glass I ordered from the local glass shop, underneath the glass I placed some 4mm neoprene-like mats. This is my first close encounter with any US speaker (as you can gather from my homepage I am more familiar with German stuff) and I am REALLY impressed with the engineering quality of the drivers as well as the cabinett building. The best (I hope) is still ahead of me: Listening!

http://www.german-vintage-loudspeakers.com/navid.712/jbl-l300-before-after.htm

[MikeBrewster77]

If you click the link below you can see what the L300 looked like when I found them:

Very nice restoration! Your fanatical, obsessive perfectionism appears to have paid off handsomely. ;)

P.S., That's one helluva LP collection!

Best,
- Mike

[4313B]

Does anybody use there JBL,s for listening anymore or just to go :nutz:I prefer to listen to them otherwise they just sit and rot.
some moron had painted the entire cabinetts black.Well, maybe the previous moron to him effed up the veneer with beer and bong water. :dont-know Yeah, yeah, I know, two wrongs don't make a right.

Very nice restoration!Yep, it is always nice to see someone give some real TLC to these legacy systems we all know and love.

[Doc Mark]

Hey, Yellowshark,

Well done, Sir!! Very nice job of saving those old L300's from the skip, and giving them the respect they deserve and a new lease on life. I don't think you will be disappointed, either! Have fun with them, and thanks for sharing your great job with us. Take care, and God Bless!

Every Good Wish,
Doc (another proud L300 owner, and listener!!)

[yellowshark]

Well, maybe the previous moron to him effed up the veneer with beer and bong water. :dont-know Yeah, yeah, I know, two wrongs don't make a right.

@4313B You won't believe it but you actually came close: The speakers were taken from a brothel which closed down some twentyfive years ago; they were there to keep the girls dancing at the poles. To rule out a possible misunderstanding: I didn't take them out 25 years ago, but 2 months ago.

Well, thanks for the generally encouraging comments about the restauration. Let me just make a point about the term "restauration" as I am in fact a professional conservator (not of speakers but of antiques and paintings). And let me make this point with regards to my pedantic search for the correct position of the JBL badges on the grilles:

- Restauration means to try and put the object back in its original condition

- Renovation means to just try and make it look new

of course the badges could have been put anywhere on the grilles - they might even "look cooler in the top right corner" but I'd rather stick to the original. If possible. With support.

[pierce]

of course the badges could have been put anywhere on the grilles - they might even "look cooler in the top right corner" but I'd rather stick to the original. If possible. With support.

As the two different sets of catalog cover pictures show, there's a pretty wide range of 'original' there, so, I'd say anywhere in that lower-right corner that looks aesthetic to you is good to go. about one to 1.5 badge width from the corner looks about right to me ;)

[SUPERBEE]

I believe someone earlier determined that black picture matting from the framing shop was a good match.... :yes:

Yes, I have done this. It looks great and is a good thickness


can anyone tell me the EXACT position of this logo on the grille? Meaning: how many mm down to the front edge of the grille and how many mm to the right hand side front edge of the grille. (I also reluctantly accept inches). Thanks!

Badges go on the grill in the lower right hand corner.....OOOOPPPS

I didnt see the Ninja edit

My buddy say his badges are 2 3/8 In from both the side and bottom measuring from the edge of the badge