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KenWH
08-26-2006, 08:54 AM
Hi guys,

Need some help/advice on what to do...one of my 3160 crossovers has developed a problem.

For reference...the 3160 is currently being used to passively cross a 4675 which has a 2445j driver with a pair of 2225h woofers.

Ok the problem...
The 4675 will sound fine then out of the blue the whole speaker(all three drivers) will start crackling and cut in and out...like something is shorting out. While it's doing it if I go up to the speaker and tap one of the woofers the sound comes right back. Also it only seems to have the problem when it's playing at lower volumes. As long as it's cranking high spl's it won't do it.

I know it's this one specific x-over unit cause it was originally installed on my right front 4675 when the problem started, but I just swapped the x-over to the left which was working fine and now it started doing it.

So what do I need to do...I guess opening 3160 is the next step...what should i be looking for as a possible source of the problem inside the x-over?

Thanks in advance,
Ken
Zilch
08-26-2006, 11:12 AM
Loose or oxidized input connections/terminals.

When you crank it up, the voltage gets high enough to punch through it.

The fact that the entire speaker is intermittant tells me it's the input.

First thing I replace on many of those old crossovers is the corroded screws attaching the terminals from the inside, using stainless.
johnaec
08-26-2006, 04:17 PM
'Might want to pick up a spare, (no affiliation): http://cgi.ebay.com/JBL-3160-Network-Pair-Vintage-Audio-Theatre-HIFI-Net_W0QQitemZ180022340132QQihZ008QQcategoryZ3284QQ rdZ1QQcmdZViewItem

John
subwoof
08-26-2006, 06:56 PM
Don't forget to tighten the screws that are there already. better that 75% of *ALL* older JBL crossovers, drivers and misc networks that I have seen have connections that have loosened over time...

The woofers seem to be somewhat immune to this issue.

I walked into a theater one night before a show and the techs all had various theories on what the mystery " distortion" was.

After climbing up to each recessed cluster, and tightening all the bolts on the INSIDE of the 2" drivers, nary a peep was heard again.

To get paid for it, and the respect of your fellow sound techs ( and free beer ) was priceless..

sub