HELP! 2421B Diaphrams for LE85

[majick47]

The JBL pro shop just called me and wanted to know if the replacement diaphrams (2421b) for my LE85 horns in my L200b speakers are 8ohm or 16ohm. Once they ship them to my JBL pro shop I own them and if I get the wrong ones it would be a costly mistake. As always I'm depending on your expert advice.

[4313B]

The LE85/2420/2421B takes the D16R2421 diaphragm.

The 2421A (original 4430) took the D8R2421 diaphragm.

[gerard]

hello

impedance should be written on the driver ! on the back of it .

best regards

Gerard

[majick47]

RE the L200b LE85 replacement diaphrams from JBL as suggested by gerard I will check the driver label for the impedence to see for sure if they are 8 or 16 ohm. For all I know the original L200b LE85 drivers could of been swapped out and this is the only way to verify whats actually in there. After a brief conversation with the JBL Pro tech I'm fairly certain I'll be pulling all the components (LE85 horns/136a woofers/crossovers) and have him do a complete check up and replace any worn out parts. Appreciate all the info and advice and will update you as to the results. After reading a number of posts I now clearly understand these vintage speakers will need a serious tune up being 30+ years old.

[Mr. Widget]

Originally posted by majick47
...I will check the driver label for the impedence to see for sure if they are 8 or 16 ohm.

Don't bother.

As Giskard posted the LE85 takes the D16R2421 diaphragm which is the one for the 2421B. Your LE85 will probably say 8ohm, don't be fooled by this. If you do some searches you will find several threads discussing this. The short answer is that the LE85 was originally labeled 16ohms and later labeled 8ohms. There is no difference. JBL never changed the impedance just the name tag. All LE85s and 2420s used the same diaphragm. Later when they came out with the 2421 they did offer it in two impedances. The "8 ohm" 2421A and the "16 ohm" 2421B.

Really it is true!

Widget

[gerard]

Mr Widget


Following your last input ....

I have a 2420 driver labelled 16 ohms ?
Is it a 16 ohms or 8 ohms ?

I have got to replace the lpad installed on it so shall I buy a 16 or 8 ohms Lpad ?
best regards

Gerard

[4313B]

Did I not just post that the LE85/2420/2421B takes the D16R2421 diaphragm? JBL discontinued the D16R2420 diaphragm.

If the L-Pad you're replacing is a 16 ohm L-Pad then replace it with a 16 ohm L-Pad.

[Tom Loizeaux]

It is important to use the "correct" impedance diaphragm when using a passive crossover. You need to confirm the impedace your compression drivers. I suspect they are 16 ohm units. The L-Pads may also be a clue. A 16 ohm compression driver will show a resistance of around 7 to 9 ohms on a VOM meter.

Tom

[4313B]

Ok... one last try... the LE85/2420/2421B takes the D16R2421 diaphragm. It's a "16 ohm" diaphragm.

Numerous people have already posted this but here it is again. Print it out and take it to your Pro shop as a courtesy. Perhaps let them keep it for future reference.

[majick47]

Giskard and Mr. Widget to the rescue again of a poor novice. Last evening while working I spent serious time trying to do the research in the JBL library and forums but due to the slow as mollases pc I was at it forever and never got to the L200b Tech manual. I will pass a copy on to my JBL Pro shop for future reference. Also as I mentioned I will have the Pro shop inspect all my woofers/drivers/crossovers suspecting that someone may have "messed" with one of the crossovers to accomodate the aftermarket 8ohm diaphram in one of the LE85 horns. This is what caused me to be confused re 8ohm/16ohm rating.