Rudy Kleimann
10-02-2005, 10:04 AM
I have a fine old pair of L166's that I just revived after many years of sitting in the closet for want of a tweeter. Now I have the tweeter, and am ready to use them.
I have one problem though: when I bought these 15 years ago, they lasted a year before the foam surrounds began crumbling. I had them refoamed, and discovered the woofers were wired "out of phase". Out of ignorance, I attempted to "correct" what I thought were "incorrect" wiring phasing on all the drivers. Shortly thereafter, one tweeter failed for unclear reasons, and the fun was over.
I have learned a great deal since then about crossover driver phasing as well as JBL's unique "polarity convention". Enough to know that it is hard as hell to get right on your own without test equipment. I have searched for and finally found an official wiring diagram for these in a copy of the JBL L166 owners' manual, but the graphic is unreadable.
I know I have the woofer and the cabinet input terminals right, but the mid connection is questionable, especially after connecting my new 2012H full-range in parallel with the 166's and getting the "out of phase" sound. I have read here somewhere that my L166 cabinet as a whole is "reverse polarity convention" just like my 4311's are. I run them out of phase from the amp to the cabinet in an attempt to maintain proper absolute polarity.
The 066 tweeter is supposedly a "reverse polarity convention" driver too. The wiring markings and the driver connection posts' color is the only definitive answer for me to get the entire cabinet in sync with itself.
Can anyone provide a readable schematic for the L166 drivers and crossover? I would really appreciate it. any other tricks, like the audiophile "bypass capacitor" trick on the 066 tweeter x-over I've read elsewhere on this forum, would be appreciated too.
I have one problem though: when I bought these 15 years ago, they lasted a year before the foam surrounds began crumbling. I had them refoamed, and discovered the woofers were wired "out of phase". Out of ignorance, I attempted to "correct" what I thought were "incorrect" wiring phasing on all the drivers. Shortly thereafter, one tweeter failed for unclear reasons, and the fun was over.
I have learned a great deal since then about crossover driver phasing as well as JBL's unique "polarity convention". Enough to know that it is hard as hell to get right on your own without test equipment. I have searched for and finally found an official wiring diagram for these in a copy of the JBL L166 owners' manual, but the graphic is unreadable.
I know I have the woofer and the cabinet input terminals right, but the mid connection is questionable, especially after connecting my new 2012H full-range in parallel with the 166's and getting the "out of phase" sound. I have read here somewhere that my L166 cabinet as a whole is "reverse polarity convention" just like my 4311's are. I run them out of phase from the amp to the cabinet in an attempt to maintain proper absolute polarity.
The 066 tweeter is supposedly a "reverse polarity convention" driver too. The wiring markings and the driver connection posts' color is the only definitive answer for me to get the entire cabinet in sync with itself.
Can anyone provide a readable schematic for the L166 drivers and crossover? I would really appreciate it. any other tricks, like the audiophile "bypass capacitor" trick on the 066 tweeter x-over I've read elsewhere on this forum, would be appreciated too.