PDA

View Full Version : 126A replace with 128H-1



warpig
09-22-2012, 09:37 AM
Hello all

I posted in another thread that the 126s's were going out in my L65's. I purchased a set of 128H-1's off of eBay. I read that I should switch the positive and negative when substituting another speaker for the 126A. Would this apply? Also should I modify the network if so could someone recommend the modification?

Appreciate any info.

Thanks
greg

boputnam
09-22-2012, 11:42 AM
Hello all

I posted in another thread that the 126s's were going out in my L65's. I purchased a set of 128H-1's off of eBay. I read that I should switch the positive and negative when substituting another speaker for the 126A. Would this apply? Also should I modify the network if so could someone recommend the modification?

Appreciate any info.

Thanks
gregGood question. Actually, all questions are good if the answer helps...

My notes has the 126A as a true aberration of the norm of vintage JBL drivers - it is Positive. The 128H is Negative. So, when you mount the 128H merely reverse the connections to the driver - this will maintain the cabinet polarity JBL intended.

btw, I expect you will find the 128H a pretty big improvement.

warpig
09-24-2012, 04:40 AM
Thanks for the quick reply. I did change out the drivers yesterday and did as you suggested and yes they do sound better. :-)

I rebuilt the networks a little less than a year ago. Looking back on it I wish I would have built them to the L65B specs instead of the Jubal specs. All drivers are the same expect the woofer's and I would assume they changed the network specs for the better.

When I rebuilt the network's I left the auto transformer (is that correct) in and changed everything else. Hope this helps some in the future.

Thanks Again
greg