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rjw
06-26-2014, 12:25 AM
I have a pair of JBL 4341's from the seventies that I am in the process of reviving, and I have a question

I brought the 15's to get new foam surrounds in that they were completely gone and the tech told me that the spiders were weak??

He explained that the spider should better support the cone and that if changed, that the speakers would support more power before bottoming out.

Is this really necessary in that the cabs are only rated at 75 watts to begin with? Will I be losing sensitivity??

speakers are 2235A's I think

thanks

btw: AT the moment, I have another pair of 15's in the cabs and everything seems to work fine

ivica
06-26-2014, 01:43 AM
I have a pair of JBL 4341's from the seventies that I am in the process of reviving, and I have a question

I brought the 15's to get new foam surrounds in that they were completely gone and the tech told me that the spiders were weak??

He explained that the spider should better support the cone and that if changed, that the speakers would support more power before bottoming out.

Is this really necessary in that the cabs are only rated at 75 watts to begin with? Will I be losing sensitivity??

speakers are 2235A's I think

thanks

btw: AT the moment, I have another pair of 15's in the cabs and everything seems to work fine

Hi rjw,


From the explanation in the:

http://www.jblpro.com/pub/obsolete/4340_4341.pdf

it seems to me that the Bass driver is 2231A (Alnico), not 2235H (ferrite) so rated power has not to be over-passed, in order to protect the 2231A from being demagnetized. Owing to 2231A large Vas, it would be expected that it has quite soft spider, so I can suggest You only to bay 2231A appropriated (re)-foam and apply to 2231A. Here on the forum, You can seen that a lot of members are very satisfied with the Rick's Cobb [ e-maiL: rcobb@tampabay.rr.com ] foams for the 2231A/2235H.
I think that reaching Fs=16Hz will never can be get , but around 20~24Hz can be expected (after "burn-in"-after some time of use) .

Regards
ivica

rjw
06-30-2014, 08:22 PM
Should have them back in a few days. 2231A's = Yes

Meantime, I have another set of 15's in the cabs temporarily and the good news is that everything else seem to work fine!! Amazing, in that they sat unused since the early 80's.

I am curious as to what they would be worth?