What the difference in the LE 20s and the LE 25s? Size? Sound? Efficiency? thanks!
Printable View
What the difference in the LE 20s and the LE 25s? Size? Sound? Efficiency? thanks!
Come on, someone knows this. :)Quote:
Originally Posted by midlife
have you tried doing a search??Quote:
Originally Posted by midlife
What is the reason for the question? round flange vs. square flange...
hard flange vs. foam, diffraction-reducing ring, possibly different magnet
material later (?). They're paper tweeters that evolved and were used in
many designs. Hard to get too excited about it.
Well, if you're talking about the LE20, or more commonly the LE20-1, these were both Alnico based paper cone tweeters. Most of the time, these were 8 ohm drivers, nominally 1.4 inch diameter, with a voice coil about 0.75 in. diameter, 3.7.4.2 ohm DC resistance. All seem to have round faceplates with 2 or three fixing holes.
I didn't know this till I just looked it up, that the early LE20 has a cast aluminum frame with black crinkle paint finish like most of the LE series, an outer screen covering the cone, and has typical JBL push terminals and screw down fixations for the magnet and cone/voice-coil mounting plate.
These tweeters used a single or double roll of the paper edge as the surround.
See photos below.
The later LE20-1 appears to be a later version with a somewhat cruder outer magnet/return structure casing and a revised front voice coil/cone/mounting plate that screws on to the magnet from in front. However, the basic cone/voice coil looks like a holdover. I suspect it was much cheaper and easier to produce without much change in the sound. These were used in speakers like the original 4310 and before.
The LE25, to me at least, is the ferrite conversion version of the LE20 but with newer faceplates that were square. Most faceplates started with flat and had open cell foam (that deteriorates with time) or neoprene surrounding the cone termination. The evolutionary LE26 used a shallow hill tapered plate over the usual mounting plate to provide diffraction control.
All of the LE25 based tweeters used a paper cone but seem to have the same double roll paper suspension but doped and seemed taller (usually about 1/4 inch tall) above the mounting plate - best seen on the common L100 tweeters where the foam is gone. They seem to be sitting, at the outer edge, on top of a doped fabric/linen not unlike typical spider material.
Hope this is a good start.
LE20-1 pics below, note the change to solder points instead of push terminals, and the cast casing and less machined front plate. There is usually a trim ring covering the plate mounting holes.
I sort of think that the LE20 sounded a little better but the LE25 would handle more power or take more abuse. The surrounds were different on them.
Mike
LE25's came in many different flavors depending on the application. 4313B had compiled a chart which listed the different types with the VC specs, wire types, and relative frequency response characteristics. You'll have to search for that.
Pics below - LE25 foam gone, front, back - note they always had an orange surround; LE25-4 with neoprene front and back, black surround doped.
LE26 variant, seen on L19, L50, 4301B, but NOT the L40!
Hey Bart. Midlife owes you a big hug :D
Thanks one and all. Appreciate the pics and explanations. :applaud:
my L40's have the 033.Quote:
Originally Posted by mech986
The LE20-1 was simply an LE20 with the fancy front and back covers removed to decrease baffle real estate cost. JBL decided not to apply the crinkle finish to the LE20-1 since it was a "system only component" and not part of the Loudspeaker Component Series. Additionally they covered the exposed front plate with the black foilcal ring.Quote:
The later LE20-1 appears to be a later version with a somewhat cruder outer magnet/return structure casing and a revised front voice coil/cone/mounting plate that screws on to the magnet from in front. However, the basic cone/voice coil looks like a holdover. I suspect it was much cheaper and easier to produce without much change in the sound. These were used in speakers like the original 4310 and before.
The LE26 is probably the "best" of the bunch.
OOPS! Absolutely correct, I'll fix that in my post.Quote:
Originally Posted by SEAWOLF97
Thanks for the clarification on the LE20 transition. I agree with you about the LE26, I think it sounds the best of the bunch and is so much easier to deal with without the foam or neoprene. It looks much more "finished" and I prefer it in the L100, although it doesn't make a huge difference in the very top, they all roll off before 15K IIRC.Quote:
Originally Posted by 4313B
I think this guy agrees....Quote:
Originally Posted by 4313B
http://www.troelsgravesen.dk/JBL_LE20-25.htm
http://www.troelsgravesen.dk/JBL_LE26.htm
dig around his site (
http://www.troelsgravesen.dk/Diy_Lou...ts.htm#Vintage Loudspeakers )
and you'll find his 'L100' project, L26 rebuild and conversion to L36, but using his crossover design. Someone should send him some $9.99 horns and compression drivers to play with...:D