L300 xo - 4313b vs np

[audiomagnate]

I have a DCX 2496 that can do all that and I have triamped L300s with DSP in the past with great results, but these are for a buddy that wanted something simple. Stock L300s sound excellent to me. These didn't with the Nelson Pass crossover so I simply went back to the original phasing, which makes perfect sense and is verified by listening and measurements. This ain't rocket science.

[Ian Mackenzie]

In order to assist in resolving audiomagnate's concerns I referred your post to Nelson Pass who has requested I post his reply and a frequency response taken of the stock L300 and the modified L300 with the revised crossover.


Quote
"Hi Nelson

It would seem there is a difference of opinion on the L300 passive crossover?
Regards

Ian"

Quote
"BTW, I looked it up, and here are the curves of the loudspeaker
before and after. Clearly the phase of the crossover was not
altered from the original.

Perhaps this gentleman confused the white and black wires
of the crossover with the red and black of the midrange. My
reference was to the actual terminals on the driver.

np"


Below are links to others who have followed and built the Nelson Pass modified L300 crossover:

http://www.audioheritage.org/vbullet...by-Nelson-Pass

http://www.audiokarma.org/forums/ind...-l300s.502767/

Quote
"I got one speaker done last night and was able to A/B between the new and old crossovers. WOW what a difference! I thought the old ones were good and couldn't imagine a HUGE improvement but thankfully I was wrong. Everything is SO much clearer and less grainy sounding in the HF. The bass is now shockingly well defined too - going back and forth between the two speakers (old vs. new xover) its amazing to me how seemingly blurred together all of the instruments are in the old vs. the new. Needless to say I am blown away and am putting in the second new crossover STAT . Thanks to Duaneange and dnewma04 for all their help with this!

https://www.stereo.net.au/forums/top...n-pass-x-over/"

[jfine]

I would stick with stock 300 xover design, but lose all the mylars and those wax filled caps in the resin box (leave em in, just unhook them), stock resistors, and use very nice caps, jupiters/sonicaps, mills resistors. Solens, Clarity, Daytons, etc., wasting $$$ and time, IMHO.

[Ian Mackenzie]

It makes sense to start with the L300 crossover so you can appreciate the qualities of original design.

But it appears you have been attempting to repair the original crossover and had other concerns with the compression driver looking at your earlier posts.(It might be more beneficial to continue in your original thread so the history of your journey can be seen before contributing or answering further questions.)

Have you resolved these earlier concerns?
If this is not the case my suggestion is start at the start and get the compression drivers serviced by a Jbl repair agent.
Then arrange new build of either the standard crossover (see L300 equivalent schematic) or the Pass modified L300 crossover.. The differences are discussed in the Pass article.

Fellow members have previously offered to do this for you.

The original Jbl crossovers are built and assembled in a way that only the factory or a service agent can repair. The complexity, potting of parts, wire colour codes, Jbl polarity conventions are easily confused by the diy loudspeaker person.

This came out in conversation with Nelson Pass yesterday.

In terms of diy you are better served to start a fresh and build a new network. Follow the schematic carefully and the parts list if provided. Ask or obtain help if you are unsure how to assemble a passive crossover and install it.

Good luck with your project.