5235 18dB cards Help Needed

[Ralf]

I want to have 18dB cards with following cut off frequencies:

50Hz, 60Hz and 70Hz for testing with my new 4 2245 cabinets

But in the manual of the 5235 there is only a 80Hz card.

Does anybody knows the formula? Or other infos about?

Thanks

Ralf

[Robh3606]

Here it is it's in the manual



http://www.jblproservice.com/navigation/Vintage%20JBL-UREI%20Electronics.html

Just look through the list


Rob:)

[Ralf]

Originally posted by Robh3606
Here it is it's in the manual



http://www.jblproservice.com/navigation/Vintage%20JBL-UREI%20Electronics.html

Just look through the list


Rob:)

Thank you Rob for the answer. But this is the formula for the 12dB card...

Ralf

[Ralf]

Ok., nobody knows a formula.

Does anybody know, which RC combination is for the low and which is for the high pass?

I try to find out how it is to calculate. Maybe I will find a row in the other 18dB cards described in the manual and maybe I can derive a formula...

Ralf

[4313B]

Some crossover Card schematics are in this thread.

http://audioheritage.csdco.com/vbulletin/showthread.php?threadid=980&highlight=crossover+card

For 50 Hz low pass try
R1=R2=R3=11 kohms
C1 = 0.36 or 0.39 uF
C2 = 1.0 uF
C3 = 0.056 uF

For 60 Hz low pass try
R1=R2=R3=13 kohms
C1 = 0.27 uF
C2 = 0.68 uF
C3 = 0.039 uF

For 70 Hz low pass try
R1=R2=R3=20 kohms
C1 = 0.15 uF
C2 = 0.39 uF
C3 = 0.022 uF

"I try to find out how it is to calculate. Maybe I will find a row in the other 18dB cards described in the manual and maybe I can derive a formula... "

Good idea. If you play around enough you should get closer than what I've posted although I think the 70 Hz values are pretty close (-3 dB at 73 Hz in a simulator). If you go with precision resistors you should be able to get pretty decent results.