Check the crossover and found that
two resistors (20 Ohm 10F) are broken ,
1 of the 2 capacitors (1.5uf 200v) - wire leads broken.
(see marked in red)
No escape must renew it !
see crossover scheme here:
http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=27107&stc=1&d=1186327266
Must replace list:
L-pads:
16 ohm for the LE85 (although written 8ohm on the back of it)
the other one 8ohm for the 077.
can i replace with 8ohm/50W ?
Or 16ohm is a must?
two ceramic resistors 20 Ohm 10F
2 capacitors 1.5uf 200v
1 capacitor 1uf 200v
Any recommendations what caps/resistors should I order?
Do u see any point replacing the other 2 resistors that
are accessible (see mark in blue)?
from the crossover scheme it must be:
10ohm 20W
7.5OHM 40W
I found same resistors but i think both are quite old (but NOS).
So not sure if replacing them is good idea.
what do u think?
Any other tip are welcome- Thanks!
two resistors (20 Ohm 10F) are broken ,
1 of the 2 capacitors (1.5uf 200v) - wire leads broken.
(see marked in red)
No escape must renew it !
see crossover scheme here:
http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=27107&stc=1&d=1186327266
Must replace list:
L-pads:
16 ohm for the LE85 (although written 8ohm on the back of it)
the other one 8ohm for the 077.
can i replace with 8ohm/50W ?
Or 16ohm is a must?
two ceramic resistors 20 Ohm 10F
2 capacitors 1.5uf 200v
1 capacitor 1uf 200v
Any recommendations what caps/resistors should I order?
Do u see any point replacing the other 2 resistors that
are accessible (see mark in blue)?
from the crossover scheme it must be:
10ohm 20W
7.5OHM 40W
I found same resistors but i think both are quite old (but NOS).
So not sure if replacing them is good idea.
what do u think?
Any other tip are welcome- Thanks!
Attachments
Last edited:
Last year I rebuild the crossovers in my L-220 that I had bought back in the 1970s. I used a combination of the following, 12ga Alpha Core chokes, Mundorf silver oil caps, Jupiter Vintage Flat caps, Sonicap Gen 1 caps and Mills MRA 12w resistors. I also replaced the mid frequency L pad with a 100w unit. Left the tweeter L pad alone. The parts ended up costing more than I paid for the speakers!! The overall effect to my ears was a smoother sound stage with more depth than the stock crossovers. I also got rid of those crappy JBL twist lock speaker connectors.
YMMV
David
YMMV
David
Nelson has an article on "improving" the JBL L300 XO on the Firstwatt site:
http://www.firstwatt.com/pdf/art_l300.pdf
http://www.firstwatt.com/pdf/art_l300.pdf
Thanks drpro!
L220 - love them .... Im sure you took them even to higher level with the new parts.
problem with the L300 is that some of the caps are deep in some wax and sand .
so at this point i want to replace what is accessible,
see my previous post :
two ceramic resistors 20 Ohm 10F
can i use these one:
RS01020R00FE12 - VISHAY DALE - Through Hole Resistor, Wirewound, RS Series, 20 ohm, 10 W, ± 1%, Axial Leaded | Newark element14
2 capacitors 1.5uf 200v
1 capacitor 1uf 200v
Replace with ClairyCap ESA series:
1µF / 250VDC
1.5µF / 250VDC
for the Lpads :
I see many replace with 100W - why??
50W will not be enough?
16 Ohm:
Speaker L-Pad Attenuator 50W Mono 3/8" Shaft 16 Ohm
8 Ohm:
Parts Express Speaker L-Pad Attenuator 50W Mono 1" Shaft 8 Ohm
jackinnj,
Thanks for the link,
Interesting..
Is there anyone who tried and can confirm the results?
I read some reports saying the bass doesn't go low as original design .
(I love bass🙂)
How come he use 8Ohm LPAD for both mid and the tweeter?
Original was 16ohm for the LE85.
L220 - love them .... Im sure you took them even to higher level with the new parts.
problem with the L300 is that some of the caps are deep in some wax and sand .
so at this point i want to replace what is accessible,
see my previous post :
two ceramic resistors 20 Ohm 10F
can i use these one:
RS01020R00FE12 - VISHAY DALE - Through Hole Resistor, Wirewound, RS Series, 20 ohm, 10 W, ± 1%, Axial Leaded | Newark element14
2 capacitors 1.5uf 200v
1 capacitor 1uf 200v
Replace with ClairyCap ESA series:
1µF / 250VDC
1.5µF / 250VDC
for the Lpads :
I see many replace with 100W - why??
50W will not be enough?
16 Ohm:
Speaker L-Pad Attenuator 50W Mono 3/8" Shaft 16 Ohm
8 Ohm:
Parts Express Speaker L-Pad Attenuator 50W Mono 1" Shaft 8 Ohm
jackinnj,
Thanks for the link,
Interesting..
Is there anyone who tried and can confirm the results?
I read some reports saying the bass doesn't go low as original design .
(I love bass🙂)
How come he use 8Ohm LPAD for both mid and the tweeter?
Original was 16ohm for the LE85.
Last edited:
An excellent article on your specific crossover. You cannot get better advice than from an expert in the field of sound.
Thanks wdecho,
agree ,
see Q in my previous post regarding NP design.
I think even if i go for NP crossover ,
I still want/need to repair the original ones.
agree ,
see Q in my previous post regarding NP design.
I think even if i go for NP crossover ,
I still want/need to repair the original ones.
JBL L-300
With some careful work you can remove the adhesive and the wax. I have attached a photo of the completed crossovers. The photos are before I added the larger L-pad. The midrange will/can handle more power thus the 100w L pad. Over the years I had to replace both pads in both speakers. I was using an Adcom GFA-555 to drive them. Now I have built a F-4 with BA-3 preamp. Very nice compared to the Adcom. My plan for the new year is to build another F-4 and convert the amps to balanced inputs for 100w mono blocks and the BA-3 to balanced outputs with Jensen transformers.
With some careful work you can remove the adhesive and the wax. I have attached a photo of the completed crossovers. The photos are before I added the larger L-pad. The midrange will/can handle more power thus the 100w L pad. Over the years I had to replace both pads in both speakers. I was using an Adcom GFA-555 to drive them. Now I have built a F-4 with BA-3 preamp. Very nice compared to the Adcom. My plan for the new year is to build another F-4 and convert the amps to balanced inputs for 100w mono blocks and the BA-3 to balanced outputs with Jensen transformers.
Attachments
Great work drpro!
Wish I have a knowledge to full repair ,
For the lpad - in the original scheme look they used
Even lower.... 16 ohm 30w
But need to start with something for beginners ,
Can u /someone help with what should parts list should order ?
two ceramic resistors 20 Ohm 10F
I would choose mills buy they are 12w
Not sure if the wattage is important in this case,
can i use these ones;
RS01020R00FE12 - VISHAY DALE - Through Hole Resistor, Wirewound, RS Series, 20 ohm, 10 W, ± 1%, Axial Leaded | Newark element14
2 capacitors 1.5uf 200v
1 capacitor 1uf 200v
Replace with ClairyCap ESA series:
1µF / 250VDC
1.5µF / 250VDC
Original ones are 200v
Wish I have a knowledge to full repair ,
For the lpad - in the original scheme look they used
Even lower.... 16 ohm 30w
But need to start with something for beginners ,
Can u /someone help with what should parts list should order ?
two ceramic resistors 20 Ohm 10F
I would choose mills buy they are 12w
Not sure if the wattage is important in this case,
can i use these ones;
RS01020R00FE12 - VISHAY DALE - Through Hole Resistor, Wirewound, RS Series, 20 ohm, 10 W, ± 1%, Axial Leaded | Newark element14
2 capacitors 1.5uf 200v
1 capacitor 1uf 200v
Replace with ClairyCap ESA series:
1µF / 250VDC
1.5µF / 250VDC
Original ones are 200v
Last edited:
I took the two charts from the article and tried to get similar x-axis data points, the trace for the "original" was adjusted such that they are both equal at 100Hz, not quite as rigorous as one would like. It appears that the modified unit is not lacking in low end performance:
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