Can the poly 104H be considered a drop in replacement for the LE5's in my CC'd L212's

[kelossus]

Just a quick question as per the thread title.

I have a spare pair of freshly reconed 104H's and was wondering if I they are compatible in the L212's.

I have a pair of N212's biased crossovers built to 4313b's posted schematics.

I tried searching for this answer but I couldn't find it and I am not switched on enough to draw any conclusion from the technical data available on the drivers.

[Earl K]

Undoubtedly, JBL designed different le5 variants for quite specific system applications ( therefore, a different variant is rarely going to be "a drop-in replacement" / unless the only change in model#, represents the paint colour ) .

Perhaps you know this and you were just careless when using the phrase "drop-in replacement".

Semantics aside, I would simply try the swap & if it's deemed to be desirable to your ears , that attraction might be attributable to something akin to "implementing the well-regarded BBC Dip" ( even if achieved solely through using a less dynamic driver ) .

I would certainly make sure that the 2 model types share the same polarity convention ( ie; with the raw driver, apply dc voltage from a 1.5v battery to similar connectors and observe the direction of cone movement ) .

[gasfan]

I subbed in 104H-3 in place of LE5-5 in my L65s but I can't say I hear a dip. What I do hear though, is more complete upper bass/lower mid. I suppose that may as well constitute attenuation.

[jlyons]

Kelossus, one indication of the upgrade 104h series offered over the LE5s was the deletion of the little inductor which tamed an output bump in systems like L110 and L86, 96, 112,etc which utilized LE5s with the 3.5 mH , which is absent in later(104H) networks, such as the NL 100T3, so I imagine that would constitute a change of some significance,( I, too, would listen before changing.) The poly 104h also differs from the 104h-2, each has the 1" voice coil instead of the LE5 .875"

[DavidF]

Just a quick question as per the thread title.

I have a spare pair of freshly reconed 104H's and was wondering if I they are compatible in the L212's.

I have a pair of N212's biased crossovers built to 4313b's posted schematics.

I tried searching for this answer but I couldn't find it and I am not switched on enough to draw any conclusion from the technical data available on the drivers.

The poly cone mid measures quite differently than the paper cone varieties. The 104H is less sensitive, the impedence is lower and the high end roll off is more pronounced. Can't say how all these add up to changes in performance but the potential is pretty high for a mismatch with the LE-9 or similar.

[kelossus]

Yes I was more interested if the LE5 crossover section in the N212's would accommodate the 104H's or if there would be some sort of adverse effect when the 104H is installed and it would not be performing to its potential.

How would the 3.5MH inductor which from memory has a high dcr effect the 104H if installed.