The OFFICIAL JBL Owners Thread - Page 520 - AVS Forum
Forum Jump: 
Thread Tools
post #15571 of 15571 Old Today, 02:19 PM
AVS Special Member
4DHD's Avatar
Join Date: Aug 2004
Location: sierra ecuadoriana
Posts: 5,856
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Liked: 74
Originally Posted by gferrell View Post
So what are the principals of a bias XO? How do you go about doing it?
Go over to
Search for Charged-Couple Networks.

What it involves is changing the caps. Lets say the tweeter circuit has an 8uf cap and a 4uf cap.
The 8uf is replaced with two 16uf caps, wired in series.
The 4uf is replaced with two 8uf caps, also wired in series.

You do the same for all caps.

The common points of each pair of caps are connected to 2 megohm resistors.
The other ends of the resistors connects to the + side of a 9v battery.

This does two things, the 9vdc keeps the layers of the caps tight.
And it also keeps the audio signal above the 0 volt line.
W/O the 9v charge, the layers tighten, loosen, tighten, loosen as the frequency and amplitude change. And by keeping the signal above the 0 volt line the caps are always on, eliminating a slight phase sift as the signal changes direction.

As you can see, both the doubling of size and number of caps will require a lot more space. The original L212 XO fit on one 4.5 x 7 card. The Biased XO required 3 cards, one for each driver.
4DHD is online now  
Sponsored Links
Reply Speakers

Jbl Professional , Jbl Harman Kardon , Jbl G200 Bookshelf Speakers , Jbl S Center Center Channel Speaker , Jbl Balboa Sub 10 Inch Powered Subwoofer , Center Channel Speaker Sku Pas749099 , Jbl , Jbl Northridge E30 2 Way 6 Inch Bookshelf Speakers Pair Black Ash , Jbl Lc1 3 Way High Performance Dual 5 1 4 Inch Center Channel Loudspeaker Black , Jbl Lc2 4 Way High Performance 6 Inch Dual Wall Mountable Center Channel Loudspeaker Black , Center Channel Speakers , Athena
Gear in this thread - G200 by

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off