L300's - age, diff sound & connectors

[remusr]

Hi - 3 questions about my L300 Summits I purchased in Dec/05:
1. Any idea of when they were built? sn is 14000 on one, other is hard to read. Has 136A's not 136H's, one reconed and the other refoamed, badly.
2. one L300 sounds brighter than the other and adjusting the LPads doesn't entirely compensate for the sound quality difference. Is this likely due to rediaphragms or can the crossovers vary as they age? The crossovers appear untouched but I haven't removed the LE85 or 2405's to check if the wax is there.
3. Any recommendations on replacing the rear spring-loaded & internal blade connectors? Looking more for better connection,not just prettier, altho I would pay a bit for that too!
- Thx, Roy

[norealtalent]

JBL uses a 1 mf cap in many of those older HF crossover circuits. In my experience, those are often times the cause of low or no tweeter output. I have had to change 1/3 of every pair I've had. I believe there is also a 1.5 mf in there but never had to change those. There is something about those 1mf caps that makes them suseptible to failure. The cap is right on top in the N300 and easy to change with basic solder skills. You can confirm the cap is tired by simply paralleling another 1mf with it. If your output increases as it should be, you know you found your problem. Obviously, you want to replace them in both speakers. Hope that helps.

[majick47]

The 136a woofer is the standard woofer for the L300, later L300 Summits had the 2235h woofer. You might want to have a JBL pro shop check out the woofers and properly refoam the badly done one. Another problem area could that could account for the loss of the mid and highs are the L pads that need to be cleaned. Do a search re removing the foilcals without causing damage. I replaced the plastic twist connectors with Parts Express #091-340 speaker wire connectors for $7 a pair.

[remusr]

majik - my foilcal says L300 Summit but I have 136A's. I thought the last L300's had 136H's? Bigger motor and more power handling than 136A's?

**But can the serial number(s) be used to date the speaker or individual drivers???

[4313B]

I thought the last L300's had 136H's?

They did.

[SteveL300]

My L300's came with 136H's

[57BELAIRE]

The 136a woofer is the standard woofer for the L300, later L300 Summits had the 2235h woofer. You might want to have a JBL pro shop check out the woofers and properly refoam the badly done one. Another problem area could that could account for the loss of the mid and highs are the L pads that need to be cleaned. Do a search re removing the foilcals without causing damage. I replaced the plastic twist connectors with Parts Express #091-340 speaker wire connectors for $7 a pair.

Actually, I think the L300 Summit predates the L300 (Northridge facility).

I just recently posted a thread showing the 136H (2231H) and how to safely remove the foilcal enough to get that one last screw.

My N333 had no output to the 077...I pick it up today so we'll see if it was indeed a faulty 1 mf cap.