PDA

View Full Version : Dumb question 5234 Xover



LE15-Thumper
05-19-2005, 11:03 AM
I bought two of these because a screaming deal presented itself.
Dumb question :
My unit uses screw terminals on the back for the connections. It may have been mod'ed, I am not sure. Is this unit used between power amp and speaker or between preamp and power amp ? I just quickly glanced at them then put them away for a future project. I am quite sure it must be low level, the units are too light to be high level types.

Ok, give me your answer and any snide comments :p

4313B
05-19-2005, 11:06 AM
Between preamp and power amp.

Reference -

http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-5233&5234.pdf

http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-5234A%20manual.pdf

boputnam
05-19-2005, 01:39 PM
Yup, Giskard got that right, again... :p

Be aware the 5234 is not balanced. Other than than, it is great.

4313B
05-19-2005, 01:55 PM
Especially if you bypass all the coupling caps like the 5235 did. Use excellent caps though, something like polystyrene & foil or polypropylene & foil.

Rumor is polystyrene is history (probably because it is so excellent and quality in general is on the decline worldwide) so stock up.

pentictonklaus
05-19-2005, 02:18 PM
Be carefull when you use them the first time. They have the tendency to make a terrible #!^*** Thumpbhhh.. bahh ## noise when shut off in front of a high power amp. I used them many years on my 4350 and it hurts when you hear it. I now shut the amps off first and wait for a while. My M 552's do the same.

4313B
05-19-2005, 02:26 PM
That's why JBL had all those protection caps on their CD's back then as Ian and others have pointed out in various threads. :p I just left mine on 24/7.

Robh3606
05-19-2005, 03:45 PM
"Be carefull when you use them the first time. They have the tendency to make a terrible #!^*** Thumpbhhh.. bahh ## noise when shut off in front of a high power amp. I used them many years on my 4350 and it hurts when you hear it. I now shut the amps off first and wait for a while. My M 552's do the same."

Your not kidding! One of the dangers of not following the amps on last for power up amps off first for shut down rules. I had a power interuption last summer that was a guick on off on off twice in a row that was fast enough so it all all stayed up and sent all kinds of crap into the amps. I was real happy I had a series caps on the compression drivers. It scarred the hell out of me but it all survived.

Rob:)

boputnam
05-19-2005, 04:23 PM
OT, but...

Never had that problem with my QSC's. They power-up slow (long self-test) and power off quick, first shutting out the signal. The only "pops" I get is when I do something stupid after they're up. Yea, OK, so it happens sometimes, so what... :o:

LE15-Thumper
05-19-2005, 09:34 PM
Especially if you bypass all the coupling caps like the 5235 did. Use excellent caps though, something like polystyrene & foil or polypropylene & foil.

Rumor is polystyrene is history (probably because it is so excellent and quality in general is on the decline worldwide) so stock up.

You mean those clear caps that you see the foil inside of ?

Like these ? The on one the right has greenish color to it. Seems to be a slender roll. The ones on the left are kind of stubby and have really thin leads.
I know that the green ones on the left are supposed to be polystyrene as well.
Any comments out there ?