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View Full Version : Jbl l300 Crossover - caps and ressitor are broken HELP



karina
12-10-2015, 09:08 AM
I usually don't listen loud ,
I like the L300 but must say the bass is not that punchy and low as i wish it to be ,
the room is quite big and acoustics is not amazing
but there's lack of bass for sure - is that normal ?
or it should be really good even in large room?

I read in many forums people suggesting connecting the amp to the speakers
in opposite polarity(amp+--> speaker -), is that correct?
(tried but couldn't hear a difference)


today i turn on volume little bit and I heard some noises .

I open one the speaker crossover and found that
two resistors (20 Ohm 10F) are broken but i soldier but it look messy ,
1 of the 2 capacitors (1.5uf 200v) - wire leads broke very close to caps body so it was hard to solider back .
Noise are much less and sound is much better- but cant say bass got better,
68657

first , need help for replacing the caps and resistors on both sides
but not sure what to buy and from where.

two resistors 20 Ohm 10F
2 capacitors 1.5uf 200v
1 capacitor 1uf 200v


Is anyone tried mast mutter (Germany) crossovers?
I understand he use auto transformers .

L300
http://www.ebay.ca/itm/221683043920
Other speakers:
http://www.ebay.com/sch/mast_mutter/m.html?_nkw=&_armrs=1&_ipg=&_from=

karina
12-11-2015, 03:02 PM
Your help would be appreciated

grumpy
12-11-2015, 03:17 PM
If you are just interested in getting the crossovers going reliably, most film and foils type caps will be fine (heeding value and ratings). If you are looking to upgrade, the possibilities are endless, so you would need to state your level of interest with more focus. Nice system to work on! :)

Wagner
12-11-2015, 04:15 PM
Your help would be appreciated
Repair them first with fresh stock value parts (a re-cap: and then decide of you're still unhappy)
All of those poor old connections may be the brunt of your problems ( and unhappiness)
Signal's having to fight it's way through cold and broken joints can't be a good thing for happy sounds
Weird, all the broken joints?
Time to freshen and clean things up and reflow all of those joints that's for sure
I'd refrain from just jumping in with a "mod" or an "upgrade" just yet until I had the stock networks in proper working order

How long have you owned them and have you always felt like something was missing? If you've had them for a while and were at one time happy with their performance I'd take my advice.....................it's won't cost very much and then you'll know for sure what it is you're chasing

karina
12-13-2015, 05:57 AM
Thanks Wagner,grumpy

from the other hand there's a chance that some other components need to be replace or
even worse....
will need to recap the ones locating at the bottom (is it wax??) i think it be very challenging replacing them also.
Do u think its needed?
Ok i be optimistic and take ur suggestion and first repair the XO,
Can anyone help what the resistors and caps should order?



two resistors (20 Ohm 10F) - ceramic

I only some on Amazon "uxcell " but they look very cheap....

capacitors :

Options :

1.MultiCaps PPMFX - Metallized Polypropylene Capacitor

http://www.partsconnexion.com/capacitor_film_multicap_ppmfx.html

2 * 1.5uf / 200V, PPMFX


1 * 1uf / 200V, PPMFX


2. ObbligatoGold Premium Capacitors

http://www.partsconnexion.com/capacitor_film_obbligato_gold.html
2 * 1.5F / 630V
1 * 1F / 630V

but notice they are 630v and not 200V - i understand this is not important in this case
is that correct?
maybe other recommendation for the caps?

If there anything else i should order and replace ?

Thanks You much!

macaroonie
12-13-2015, 06:24 AM
To get the wax out of the metal box I heated it on top of a wood burning stove. The temperature was a little above what your hand will tolerate but not boiling water hot. It takes a good while , maybe 20 minutes for the wax to become liquid ( clear ).

You absolutely must establish which leads are which. Make a big printout of the circuit diagram so that you can mark up colours and part numbers or you WILL get lost.

Most of the caps have 5 digit numbers printed on them. As I remember the inductors do also but I may be wrong on that

These numbers show up on the circuit diagrams but it helps a lot to get the lead wire colours marked up as well.

Make a good note of the location of the wires that come in the multi core cable from the L pads.

Make a big diagram of the tag board and correlate it to the connection points on the circuit diagram.

68733

karina
12-13-2015, 07:36 AM
Thanks macaroonie,

Sounds like a serious work to do and require more knowledge than i have.,
I think in this case i pass ...
Good chance to asks if some one here is interested do it for me (with payment)?
Or have ones for sale...


Better start with the ones are easy to replace ,
Can someone assist with what to order?(see previous post)

frank23
12-14-2015, 12:43 PM
You can also improve the crossover for home use and go the Nelson Pass (famous audio guy) way:
http://www.audioheritage.org/vbulletin/showthread.php?32305-JBL-L300-Modification-by-Nelson-Pass

Wagner
12-14-2015, 02:14 PM
Thanks Wagner,grumpy

from the other hand there's a chance that some other components need to be replace or
even worse....
will need to recap the ones locating at the bottom (is it wax??) i think it be very challenging replacing them also.
Do u think its needed?
Ok i be optimistic and take ur suggestion and first repair the XO,
Can anyone help what the resistors and caps should order?



two resistors (20 Ohm 10F) - ceramic

I only some on Amazon "uxcell " but they look very cheap....

capacitors :

Options :

1.MultiCaps PPMFX - Metallized Polypropylene Capacitor

http://www.partsconnexion.com/capacitor_film_multicap_ppmfx.html

2 * 1.5uf / 200V, PPMFX


1 * 1uf / 200V, PPMFX


2. ObbligatoGold Premium Capacitors

http://www.partsconnexion.com/capacitor_film_obbligato_gold.html
2 * 1.5F / 630V
1 * 1F / 630V

but notice they are 630v and not 200V - i understand this is not important in this case
is that correct?
maybe other recommendation for the caps?

If there anything else i should order and replace ?

Thanks You much!


If you want them rebuilt mail them to me and I will be happy to do it
You pay for all parts and postage, that's it
(I'll prepare an open order, forward you the invoice and after you see and approve it you can pay me for the parts and I'll finalize the order (or, I'll construct an open "project" order, forward it to you and you can just use my order and place it yourself (pay the vendor(s), whatever you prefer/makes you feel the most comfortable.
I don't do Preypal for anything or any reason so we'll have to do this cash and or a credit card), or like I say, you handle it (you place the actual order and pay for it yourself).
I'm in Northern California (San Francisco suburbs; don't know where "NA" is, maybe it's close enough so that you could even drop by with your networks)
I do not believe in boutique parts, but I will use high quality film types for the primary values (Dayton, Solen or similar, your choice if you have a preference) and the Thetas for the bypass values if you insist on paying their absurd price (if you want them bypassed, which I highly do suggest and agree with) I know what I like and what seems to work well.
Dayton makes a less than one dollar metal film .01uF metal film cap that I just recently used that I can't hear any difference from the $5 dollar Thetas, so that is a very real option to keep in mind.

Others will argue this point and that's fine, I don't care (Thetas versus Daytons for the metal film types), I know what I hear and I've used both; it's about .99 cents a piece versus $5 or $6 bucks a pop
Especially as a stock rebuild may only turn out to be step one in case you catch the mod bug spiral journey.

I use ultra quite, high temp Mil-spec Vishay high temp 1% and 2% wire wound or metal film type resisters for all of my work
Good enough for weapons guidance systems and vintage tube amp's signal paths, definitely good enough for 50 years old speakers
Your call, I have cancer and a bad back an can't get around much so I'd be happy to do it
My work is pristine; if you have any of the wax filled cardboard cylinders you want re-stuffed I am experienced with handling that too. (Although I only see standard Mylars in your photos)
You want to source your own parts, that's fine too, I don't care
Best I can do for you friend; no need to re-invent the wheel for something so straight forward
I'd be happy to help

Good luck with whatever you decide to do
Thomas Wagner

mech986
12-18-2015, 04:21 AM
If the original mylar (polyester) axial caps broke a lead near the body, it was either lead (LEED not element lead) corrosion or physical failure - not easy to repair and potentially doomed to fail again, so replacement is certainly worthwhile.

With any axial capacitor, in JBL metal boxed applications, the leads must be long enough to reach the terminal pins so ask your prospective suppliers about the total length of the leads from end to end - this will prevent any issues with having to splice/solder leads.

These particular 1.0 & 1.5uf caps are in the tweeter section and another 1.5uf is in the midrange section. For some, using very good caps here will pay some dividends. I have used Axon caps from partsconnexion and they are made by the same maker of Solen caps. They are a metallized polypropylene cap. Whoops, just checked and they don't have values in your size needs, the 1.8uf cap is still too far away from 1.5uf to be usable, even at least tolerance.

The Clarity Cap PX series is a considered pretty good polypropylene cap. they have a 1.0 uf 250VDC cap at $2.87, you could buy 6 (3 each speaker) and add 4 x 0.47uf 250VDC ($2.71 caps in parallel to 4 of the 1.0 to make a 1.47uf rated cap, total cost = ~$27, and you may not need bypass caps. I'm assuming you would work on both speaker's crossovers, if not, the cost is half of stated ($13.53). The SA and ESA caps are additional steps up in possible quality and cost, approaching your Multicaps. I suspect the 630V caps may be a bit bulky though, and that's a consideration when the caps must reside under the perforated grille, and most new caps are round rather than oval like the OEM JBLs. That would be a consideration unless you leave the grille cover off the crossover.

Your Multicap PPMFX would run $9.26 each for the 1.5uf (2x) and $7.77 for the 1.0uf (1x) so total of $26.29 per speaker.

Other suppliers like parts express and madisound have additional choices. I thought you might be in Canada so I looked at partsconnexion first. they do have a lot of choices.

I agree with Wagner on the use of quality metal film or wirewound resistors, but very important to get the correct wattage - you can see that each driver uses a large wattage resistor (10ohm, 20W for woofer, 20ohm, 10W for mid and tweeter each). You'll note that in your picture, the 10ohm 20W is a large oval wirewound resistor which is ceramic / conformal coated, while the 20ohm, 10W are typical wirewound sand cast square profile - both of which also need to fitted below the crossover grille.

rusty jefferson
12-18-2015, 05:21 AM
Thanks macaroonie,

Sounds like a serious work to do and require more knowledge than i have.,
I think in this case i pass ...
Good chance to asks if some one here is interested do it for me (with payment)?
Or have ones for sale...


Better start with the ones are easy to replace ,
Can someone assist with what to order?(see previous post)



Take Wagner up on his offer to rebuild them, reinstall them, enjoy them. That was a very generous offer. If it's still not the sound you're looking for, you'll at least be passing something on the the next person that's not bastardized (if that's aword).

Doc Mark
12-18-2015, 07:54 AM
Morning, All,

Just wanted to send a "tip O' the hat" to Wagner, for his very generous and kind offer to the OP!! Well done, Sir!! Take care, and God Bless!

Every Good Wish,
Doc

karina
12-19-2015, 02:26 PM
Wagner,

Thanks u so much !
Your kind suggestion is highly appreciated(++++)
I even asked my wife to read your answer and she said "good soul ,God bless him with good health"

I live in Israel so shipping those heavy XO back and forth will cost,
I have some other idea...
Will PM u soon.

Thanks again

karina
12-19-2015, 03:21 PM
If the original mylar (polyester) axial caps broke a lead near the body, it was either lead (LEED not element lead) corrosion or physical failure - not easy to repair and potentially doomed to fail again, so replacement is certainly worthwhile.

With any axial capacitor, in JBL metal boxed applications, the leads must be long enough to reach the terminal pins so ask your prospective suppliers about the total length of the leads from end to end - this will prevent any issues with having to splice/solder leads.

These particular 1.0 & 1.5uf caps are in the tweeter section and another 1.5uf is in the midrange section. For some, using very good caps here will pay some dividends. I have used Axon caps from partsconnexion and they are made by the same maker of Solen caps. They are a metallized polypropylene cap. Whoops, just checked and they don't have values in your size needs, the 1.8uf cap is still too far away from 1.5uf to be usable, even at least tolerance.

The Clarity Cap PX series is a considered pretty good polypropylene cap. they have a 1.0 uf 250VDC cap at $2.87, you could buy 6 (3 each speaker) and add 4 x 0.47uf 250VDC ($2.71 caps in parallel to 4 of the 1.0 to make a 1.47uf rated cap, total cost = ~$27, and you may not need bypass caps. I'm assuming you would work on both speaker's crossovers, if not, the cost is half of stated ($13.53). The SA and ESA caps are additional steps up in possible quality and cost, approaching your Multicaps. I suspect the 630V caps may be a bit bulky though, and that's a consideration when the caps must reside under the perforated grille, and most new caps are round rather than oval like the OEM JBLs. That would be a consideration unless you leave the grille cover off the crossover.

Your Multicap PPMFX would run $9.26 each for the 1.5uf (2x) and $7.77 for the 1.0uf (1x) so total of $26.29 per speaker.

Other suppliers like parts express and madisound have additional choices. I thought you might be in Canada so I looked at partsconnexion first. they do have a lot of choices.

I agree with Wagner on the use of quality metal film or wirewound resistors, but very important to get the correct wattage - you can see that each driver uses a large wattage resistor (10ohm, 20W for woofer, 20ohm, 10W for mid and tweeter each). You'll note that in your picture, the 10ohm 20W is a large oval wirewound resistor which is ceramic / conformal coated, while the 20ohm, 10W are typical wirewound sand cast square profile - both of which also need to fitted below the crossover grille.

Thanks u for your detailed answer and effort done for checking for parts availability - i really appreciate that.
had some research and i see many of the vintage restoration project done with Dayton cap,
Do u have any experience with Dayton PMPC series with 1% tolerance?
Found they have both PMPC-5.1 5.1uF and 1uF 250V caps .

checked the ClairyCap ESA series
1F / 250VDC - 7$
1.5F / 250VDC- 8$

same price range as MultiCap PPMFX ,
Which one u think will do better ?

for the resistors :

so for the 20R10F , i couldn't find any ceramic resistor that is not cheap 0.8$
except Mills but they 20R12W and not 10W - Is that an issue?
other alternative?(dont mind pay less than Mills price:))

at beginning thought replacing only the 20R10F ones(were disconnected),
but if I make order for parts maybe better replace what possible(except the one
in the wax )- what do u think ?


meaning replace also the 10ohm/20w and the other one above it?


for the 10ohm 20W -I find some from Ohmite (6.62$ each)
they look the same but not sure if the holes for the screw will fit:

http://www.talonix.com/shop/item.aspx?itemid=14165


For the other one - couldn't see the values but from scheme it look it is the 7.5OHM 40W
Should it be replace also?
case yes, I think a got bingo on this one:
http://theelectrostore.com/shopsite_sc/store/html/F407-Ohmite-New.html

but in this case i might replace old one with some old(or even older),what do u think?
maybe modern alternative?


see marked yellow
68833




Thanks again!

karina
12-24-2015, 02:33 PM
last advise before ordering MultiCap PPMFX/ClairtyCap ESA?

Do think I should replace also the
10ohm 20W
7.5OHM 40W
?

mech986
12-24-2015, 03:14 PM
last advise before ordering MultiCap PPMFX/ClairtyCap ESA?

Do think I should replace also the
10ohm 20W
7.5OHM 40W
?

Wow, both your link hits look like exact replacements. If you want to replace them, would only be money and shipping for both. Of course, you could also check the current ones for any signs of overheating or burning, and the value +/- 5 or 10%, subtract out any test lead resistance from you DMM.

You've added some nice resources for us. Let us know if you order them and if any difficulties.

audiomagnate
12-26-2015, 06:38 AM
I usually don't listen loud ,
I like the L300 but must say the bass is not that punchy and low as i wish it to be ,
the room is quite big and acoustics is not amazing
but there's lack of bass for sure - is that normal ?
or it should be really good even in large room?

I read in many forums people suggesting connecting the amp to the speakers
in opposite polarity ex(amp+--> speaker -), is that correct?
(tried but couldn't hear a difference)


today i turn on volume little bit and I heard some noises .

I open one the speaker crossover and found that
two resistors (20 Ohm 10F) are broken but i soldier but it look messy ,
1 of the 2 capacitors (1.5uf 200v) - wire leads broke very close to caps body so it was hard to solider back .
Noise are much less and sound is much better- but cant say bass got better,
68657

first , need help for replacing the caps and resistors on both sides
but not sure what to buy and from where.

two resistors 20 Ohm 10F
2 capacitors 1.5uf 200v
1 capacitor 1uf 200v


Is anyone tried mast mutter (Germany) crossovers?
I understand he use auto transformers .

L300
http://www.ebay.ca/itm/221683043920
Other speakers:
http://www.ebay.com/sch/mast_mutter/m.html?_nkw=&_armrs=1&_ipg=&_from=
Lack of deep bass in the L300s is normal. Most people assume that because they are so large that they go deep, but they don't. Adding modern, high quality subs, rolling them off at 50 Hz and stuffing the ports takes them to whole new level.

Regarding the German crossovers, I think the stock crossovers work very well, the Nelson Pass even better, and electronic crossovers the best of all. I would never add transformers to a crossover when they weren't needed. Those look like a huge waste of money. Take that money and put it towards some good subs, some big amps and an electronic crossover.

Wagner
01-05-2016, 08:32 AM
I would strongly advise getting the STOCK networks in top working order, listen a while and then identify exactly what you (may) still find lacking with your system

DON'T jump off the deep end with "mod fever" just because it looks or "reads" "good" until you know excatly what you feel is missing

You also have not shared anything about the rest of your system, power etc

Or, how long have you owned these L300s for that matter (how well do you know them already?)

You are (sounds like) preparing to make a very expensive decision (potentially) on a judgement call, sight "unheard" based on at least one box with a broken network

I would advise against it as the first step (I also wrote you a lengthy PM)

Fix/restore/repair what you have first and work from that position

My offer to refresh your STOCK networks and to make any changes as YOU SPECIFICALLY indicate still stands, but as I addressed in my PM, now that I know the distance between us you may want to rethink your plan

You'll be spending a lot of money (shipping alone), relatively speaking, on something I am certain you can have addressed where you are if you are uncomfortable trying it yourself

Still, I will be happy to do it

My approach

Thomas