2405

[delahais]

hi,
i tried to make the 3133a uhf part, and i don't understand the result you can see on this picture, i have a real pic, can someone tell me what he think about this ?.
thanks, regards

[4313B]

What you have there looks about right for the voltage drive with a dummy load.

[delahais]

Originally posted by Giskard
What you have there looks about right for the voltage drive with a dummy load.

hi GISKARD,
i don't understand what you mean with dummy load, is it too small load ? 2405-16 impedance is not 12 ohms ?
how could i make the same networks without pic? with the same frequency cut.
thanks, regards.

[4313B]

R2 on your schematic there is a 12 ohm dummy load. You're better off using an 8 ohm or 16 ohm load since that is what JBL generates their voltage drives with. In fact, do another run with an 8 ohm load and one with a 16 ohm load and post the results so everyone can see.

Don't worry about what a real 2405 load is right now. Generating an actual electroacoustic model of a 2405 to plug in as a load is probably not how you want to spend your time.

[delahais]

hi,
you can see the result of networks with 2405-8 and 2405-16.
bizarre ?:shock:
thanks for reply, jbl make me crazy !
you are right, i spend too many time on this but my wife don't want to buy me S5800
regards.

[delahais]

oops

[delahais]

the other

[delahais]

good work ?

[4313B]

Yep! Looks like the voltage drive specification for that network.

[delahais]

ok,
i can ajust the level with L-pad and for you is the better way for 2405?
if i can, i would like to ask you a little thing about the high pass i've made on the picture for 2425-8 :what do you think about the caps and inductor values
thanks.

[4313B]

The best thing to do with the 2405 is to put it in front of an amplifer driven by an active filter.

Barring that your high pass schematic looks reasonable.

For the 2425 try this:

1. come up with desired resistor pad
2. create high pass filter in front of the pad
3. create low pass filter behind the pad

What horn are you using with the 2425 again?

[delahais]

i made a mistake , i was speaking of low pass filter of 2425 ,the .25mh and 2uf !
and i try to find the network best values between 2425 and 2405.
the horn is 2370.
thanks