Originally Posted by
Michael the designer
Your unit with TL082 IC's is just fine. The only upgrade path without
significant changes would be using 353LF IC's which are a nice sounding
BI-FET IC from the mid-late 80's. Do Not just change the IC's out for 353LF's without us doing the mods on the unit. It Will ring and oscillate. Our current units with NE5532's are very different circuit boards with large ground planes on both sides and individual IC
power supply filtering bypasses.
Input Section is:
20Hz HP @ 18db/OCT to Sub-Bass
20Hz HP @ 12db/OCT to Full Range
Output sections are:
Sub-Bass; 106Hz LP @ 18db/OCT - Normal
+4.5db Boost @ 43Hz w rapid cutoff below - EQ Active
Front Panel Control: Unity Gain @ 12 O'Clock. +10db at full CW rotation. Full off at CCW.
Full Range 3-way Section
Low; 1,200Hz LP @ 12db/OCT (derived from subtracting HP from FR)
+6.5db Boost @ 65Hz w rapid cutoff below - EQ Active
Mid-High; 1,200Hz HP @ 12db/OCT (no upper cut off)
High; 6,500Hz HP @ 12db/OCT (no upper cut off)
Front Panel Control: Unity Gain @ at full CW rotation. Full off at CCW.
Tweeters; 7,000Hz HP @ 18db/OCT (no upper cut off)
Front Panel Control: Unity Gain @ 12 O'Clock. +10db at full CW rotation. Full off at CCW.
Hope this was helpful to you. My engineering opinion is that 12db/OCT in the mid band is the best slope for minimal phase aberration in an analog crossover. All filters are Butterworth except my active EQ's which are an elliptical filter of my design.