JBL 4425 UK Questions

[Moko]

I recently managed to buy a pair of 4425's which are very rare over here in the UK

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpskirgkamk.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpskirgkamk.jpeg.html)

As you can see they have a very light finish and no holes for grilles does this give any indication of what year they are from? I haven't opened them up yet so no clues as to serial numbers etc.

They clearly need reconing so any recommendations of which kit to go for?

Also is it possible to dye / refinish the cabs to the more traditional walnut colour?

Any other hints / suggestions of how to proceed in returning these speakers to their former glory are most welcome.

Thanks in advance David

[SEAWOLF97]

They clearly need reconing so any recommendations of which kit to go for?

nice find , fun re-new project.

my guess is that they need new foam surrounds rather than re-coning. easy to test.

actually, I would lay them on their backs, facing up , and give them low signal to see if the LF is OK.

[Moko]

I didn't realise there's a difference between refoaming and reconing...the drivers still play music when tested so I'm not sure if that helps deciding which repair is most suitable.

Any advice is most helpful as I've never played with drivers before....only cabinet restorations

[SEAWOLF97]

I didn't realise there's a difference between refoaming and reconing...the drivers still play

refoaming is replacing the foam surrounds - well cracked in your pic- just a maintenance item.
usually about $30

reconing is replacing the paper/cardboard cones - I doubt you need that- couple hundred dollars

[Moko]

That's good news ..,any recommendations for the best refoaming kit (are originals still available)?

[Odd]

([email protected])Resurround Step-by-step (http://www.audioheritage.org/vbulletin/showthread.php?469-Resurround-Step-by-step)
Rick Cobb ([email protected]) (looneytune2001 on eBay)

[grumpy]

+1 ...and no such thing as original JBL foam surrounds being sold without being attached to a recone kit.

Rick's replacement surrounds are quite good.

[richluvsound]

PM me if you want them veneered in walnut .... The Rick Cobb kits are excellent in my experience .

best of luck with project ... Richard ,

[BMWCCA]

[QUOTE=Moko;394747]Also is it possible to dye / refinish the cabs to the more traditional walnut colour?/QUOTE]

I'm kind of fascinated by them in the blonde form. Never seen any with that finish and I kind of find it compelling for the novelty.
I think I'd leave the finish alone . . . but then they're not mine! They're yours.

Another :thmbsup: for Rick Cobb and his kits. I'm a happy customer.

[rdgrimes]

I wonder if you hit that lighter color veneer with some good old Linseed/turpentine potion - if maybe they'd darken up some. It gives the black walnut veneer a sort of reddish-brown color.

[Moko]

Thanks for all the replies....I just need to measure the cone diameter to make sure which version of the woofer I have in my speakers before I order them from Rick.

As to the speaker cabs apparently my wife likes the lighter finish so I think I'm going to clean them up the best I can and see how they look then.....if I (we) still fancy a darker walnut finish I will contact Rich and take up his very kind offer.

Have any of you ever seen 4425 without grill holes...it looks like my version was never designed to have them fitted it seems unusual but just wondered if the Pro version were made without them?

[richluvsound]

Good question .... I've only seen them with grills . Sunlight kills the foam over time . If your keeping them in direct sunlight I would advise you to get grills ....

Rich

[Lee in Montreal]

Thanks for all the replies....I just need to measure the cone diameter to make sure which version of the woofer I have in my speakers before I order them from Rick.

Shouldn't a 4425 have a 12" woofer? 4430 has a 15" woofer. The 4435 has two of the 15" woofers.

[hsosdrum]

To me the photo looks more like faded walnut as opposed to blond.

[JeffW]

http://www.jblpro.com/pub/recording/4425.pdf

2214H

I wouldn't count out the possibility that the cabs have been re-built. Of all the pics I see on the internet, none of the others have a visible seam on the ports, for instance. Post a pic with the woofer out.

[grumpy]

Shouldn't a 4425 have a 12" woofer?

yes.

2214H, iirc.

Sometimes the cone diameter varies, so it's useful to send the info to the surround purveyor when ordering.

[BMWCCA]

To me the photo looks more like faded walnut as opposed to blond.

I suppose that's a possibility! Here's a shot of a pair of L80Ts I bought. The one on the left is how I found it and the one on the right is after three coats of Watco clear oil with no color or stain added (and after a Rick Cobb surround installation).

http://i31.photobucket.com/albums/c378/BMWCCA1/DSC_1402.jpg (http://s31.photobucket.com/user/BMWCCA1/media/DSC_1402.jpg.html)

[Moko]

I'm going to make a start on the cabs and looking at the various threads I'm not sure how much to dismantle my speakers.

in general the cabs look like they just need a light sanding to get rid of the small scratches (there's no major deep scratches) and then redoing with Danish Oil (I've done this before on other speakers) and the butt cheeks also have a couple of marks on them. The woofers will obviously be removed for refoaming (I've ordered the kit from Rick)

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpsqbevbpwz.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpsqbevbpwz.jpeg.html)

So do I need to dismantle the whole horn section or can that area be tidied up without taking it apart? I'm slightly worried about dust, paint etc getting into the horn section so any tips on how to proceed are most welcome

Thanks as always

David

[Ed Zeppeli]

I would definitely want to take the drivers out before refinishing. If they're anything like the 4430s they're both front and top heavy and will have an increased chance of tipping over while you're working away. Primarily, as you mentioned, you'll want those drivers out of the room you're sanding and staining in.

The horns will require some persuasion to remove once those torx fasteners are out. There is a gasket between them and the baffle that will likely have deteriorated. You would be fine just to tape over the foilcal to prevent dust and other debris from entering the tone controls.

Good luck, have fun and go slow!

Regards,

Warren

[Moko]

Well I've taken the woofers out....very heavy...

Looking inside the cab it's full of the nasty yellow fibreglass stuff

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpsmiyqqhvr.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpsmiyqqhvr.jpeg.html)

Whats the thinking on this stuff..should I replace with more modern wave foam stuff or stick with the original dampening?

[Mr. Widget]

Looking inside the cab it's full of the nasty yellow fibreglass stuff

Whats the thinking on this stuff..should I replace with more modern wave foam stuff or stick with the original dampening?The thinking on that stuff is that it is awful to work with but sonically excellent.



Widget

[JeffW]

I still don't think that looks like a factory cab.

[mech986]

Hello and Welcome to Lansing Heritage!

here are my thoughts.

Doesn't look like the original or bleached Walnut. My opinion is it might be that the cabinets have already been reveneered in something lighter. The reason being from the one pic, the side and top are mismatched in grain, something that JBL would not do.

The lack of grille pegs or holes suggests they were filled in and the baffle repainted, not aware of any that came without grille pegs although I suppose if someone paid a lot you could have it that way. Did you ask the seller if there were any grilles? Shame really as the grilles are attractive and protective. You can order and get reproduction grille frames with fabric color of your choice from Huntley Audio here in the states. Check the recent grille fabric thread for member gsb001 for a pic of the available colors. New grille pegs can be had from Ebay seller sign-shop and holes redrilled and pegs inserted after aligning with the new grille frames.

There should also be a gasket to help seal the woofer to the baffle.

[mech986]

Can you provide some pics of the top, bottom and side veneers and how they intersect at the corners? Do you also have a picture of the back panel with attention to the connector panel?

I can see where Jeff wonders if the cabinet is original. The fiberglass inside looks disturbed, fluffed, or replaced. Normally, JBL used a matted yellow fiberglass bat about 2 inches thick compressed. In my 4425, its clean cut for the back panel and crossover - yours looks roughed up a bit so could be replaced. However, if critters or pests got inside and left evidence of habitation, it would have been prudent to replace the fiberglass. Do not use rockwool, polyester batting, foam or other damping materials - the cabinet is tuned for the OE fiberglass. See enclosed pic.

I agree with removing the horn to make it easier to work on the cabinet. Observe the wiring color code and attachments and take a pic so you can reattach correctly when replaced - same with woofer. Lay the speaker on its back and then you can unscrew the flat head hex hole (not Torx) bolts. Gently lift out the horn with driver - the horn gasket is likely brittle so don't be surprised if it comes apart. You can clean the threads and head of corrosion, if some remains, some recolor with gun bluing. It may be helpful to lightly oil the threads, then wipe clean when reinstalling and do not overtighten to prevent cracking the horn.

the horn mounting plate is screwed and glued in place so I would hesitate to remove it if you don't need to. The chip can be filled in and then the plate can be repainted.

As for the woofer, the surrounds for the 2214H are correct but measure the outer edge cone diameter and send that along to Rick Cobb as well. When you start working on the woofer, take care to gently pry up and save the front outer neoprene gasket for later reinstallation (and OEM appearance). Some like to lightly rough file the front circumference of the frame to provide a nice sharp and shiny appearance - but consider a slight filing of the frame edges to avoid any metal splinters. Then you can clean off all of the old surround foam material from the back of the cone and frame.

Prep and glue the inner diameter of the surround to the back of the cone first, then let dry 24 hours. Have some medium binder clips or large clothespins at hand. Use the tone CD sent with the surrounds as a source hooked to a small amplifier, then connected one channel to the woofer terminals. Play the CD at a low level to get a small amount of sound and to center the voice coil. Then using clips or clothespins, temporarily clamp down the outer diameter of the surround at at least 8-12 points. continue to play the tone to ensure the woofer tone is clear and undistorted. Then you can turn off the tone for now. Then remove clamps of about 1/4 or 45 deg of the circle and then glue surround to frame, then reclamp, and tone test to be sure. Repeat for the full circumference, tone test once more, then let dry for 12 hours. At the 12 hour mark, you can remove the clamps and glue on the front gasket, then let dry another 12 hours. Tone test one last time and if everything sounds good, then you can reattach wires, and then remount into the cabinet. Be careful with any screwdriver.

72927

[Moko]

Here's some more photos

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpst8babazr.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpst8babazr.jpeg.html)

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpst9rwi2ug.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpst9rwi2ug.jpeg.html)

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zps84ppqrjc.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zps84ppqrjc.jpeg.html)

As to the colour I saw one of the Kendrck sound examples that looked very similar

[Moko]

If I remove the horn you have all mentioned that the gasket is likely to disintegrate....the obvious question is then can you get replacements or make your own?

Being in the UK this is important as postage from the US is ridiculously expensive the rubber surrounds from Rick $23 postage....this seems to be standard for everything coming from US....from China it's free...Japan about $10 so it's the UPS alone charging such high rates:(

I have removed virtually all the original glue from the metal rim of the speaker spider, but to remove everything means scraping and causing lots of metal filings to be released so this is as far as I think I should go with the cleaning

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpsrmyznita.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpsrmyznita.jpeg.html)

[mech986]

Your frame prep is fine. If you're really anal about it, you can remove the old glue from the frame with acetone or methyl ethyl ketone (MEK) (or equivalent in the UK) and be in a well ventilated area when you work with solvents. Do not use solvent on the cone, it will damage it. You can scrape off all the old surround and leave the thin line of old glue on the cone, unless it peels off easily and without taking cone material with it.

As for the horn gasket, it is simply a rectangular piece of compressed foam around the perimeter of the horn. You can easily substitute draught excluder open cell foam in 3/8 to 1/2 inch wide strips, 3/16" thick but compressed down to 1/8" or less. Some of the DIY speaker bits suppliers like Falcon Acoustics or Wilmslow will likely have something similar.

http://www.jblproservice.com/pdf/Studio%20Monitor%20Series/4425LR.pdf

the above pdf is a (poorly copied) copy of the 4425 parts list and exploded diagram, showing all the parts and wiring. It is a handy reference and shows the shape of the gasket.

you may also be able to source proper foams from European sources, but you'll probably have to contact some of our Euro members for advice on who supplies the correct foams in their experience.

some like to lightly touch up the horn if its not in too bad a condition. Others will fill and sand, and then repaint - some use Duplicolor automotive paints here in the US - look for threads on lansing heritage or audiokarma.org regarding JBL 4430, 4435 or 4425 rebuilds.

[Moko]

Thanks that's great information....it looks like I'm on the right path then:)

[richluvsound]

Moko,

acetone ( nail polish remover ) will remove all the glue residue and degrease everything . BTW , where about are you in this big bad town of ours ?

Richard .

[dprice]

Here's some more photos

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpst8babazr.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpst8babazr.jpeg.html)


As to the colour I saw one of the Kendrck sound examples that looked very similar

I would guess quarter-sawn red or white oak.

Keep up the good work!

[Moko]

I'm in N London close to Muswell Hill...

Made some more progress on the cabs today...

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpsny817mkr.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpsny817mkr.jpeg.html)


http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpswmvv6b4m.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpswmvv6b4m.jpeg.html)


Just got to the masking up stage and ready to paint when the rain started....typical British Summer.

[Moko]

What is the feeling about recapping the crossovers in these speakers?

Also is it worth putting in new speaker connections and upgrading the internal wiring?

Ive not heard this set of speakers fired up properly yet as the foams where so rotted away I didn't fancy causing any further damage to the woofers....so I've no real bench mark as to how good they can possibly sound....so any advice is most welcome

[mech986]

What is the feeling about recapping the crossovers in these speakers?

Also is it worth putting in new speaker connections and upgrading the internal wiring?

Ive not heard this set of speakers fired up properly yet as the foams where so rotted away I didn't fancy causing any further damage to the woofers....so I've no real bench mark as to how good they can possibly sound....so any advice is most welcome

The capacitors in these speakers use good quality mylar caps with small polypropylene bypass caps (IIRC). There may be additional benefit to going to higher quality polypropylene caps for the large caps, but I'd really suggest just leaving them alone to see how they are stock before doing anything to the crossover circuit itself. some people do like high quality high power metal film resistors rather than sand cast encased wirewound resistors as used by JBL.

That said, it wouldn't hurt to refresh (remelt) the solder joints of all components, and changing the wiring is fine if you plan to use maybe higher quality wire and slightly larger gauge (say 14-16 instead of the 18 they typically used). Just be sure to keep the same color code if possible or specifically label each wire for its connection. As for the input connectors, It would be an upgrade to utilize high quality 5 way binding posts plated with the metal of your choice, so that you could use whatever input connector you like plus get tighter connection.

However, again, you might consider building it back to stock first, get your impressions of stock, then mod away to see if you find it makes a (positive) difference.

Yes, do not run the woofers without having been suitably refoamed - misalignment due to rotted foam will cause damage to the voice coils if run.

[Moko]

Thanks I think I'll leave them stock and just get them running again before thinking about any changes.

[Lee in Montreal]

Ah, ah, ah. The famous "improvement syndrom" ;-)
Yes. Run them as is for now. Then if you start changing caps, you will have a base on which to compare the "improvement"...
Or perhaps you can build spare sets of crossovers so that you can swap them and compare back and forth. Maybe fit higher quality components if you feel like.

Lee

[richluvsound]

Hi Moko ,


There is a lot of experience on how to refurbish the legacy speakers so they stay a legacy .... all you have to do is ask :D

Rich

[Moko]

Been busy cracking on with this restoration...

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zps0wamxsva.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zps0wamxsva.jpeg.html)

cabs now finished thanks to Osmo....a truly amazing mix of oil and wax goes on easily and doesn't seem to react to previous coatings...actually made the job a pleasure..


http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpsvi9q4ntt.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpsvi9q4ntt.jpeg.html)

Fixing the foams with the help of the CD....never tried this job before but all seem to go smoothly....lets just hope the sound from the speakers is as fine

[mech986]

They look very good so far. How did you refinish the horns and baffles? Are you going to make grilles for them?

[Moko]

I used this stuff....it's a satin finish spray paint...I think for Grafiti artists

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpsmox2pgxe.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpsmox2pgxe.jpeg.html)

and the wood work was all done with the brillant Osmo stuff...on all my previous wood work stuff I've always used Danish Oil followed by wax.....this Osmo stuff is just so much quicker and easier.

[Moko]

I'm not sure about grilles....I've never been much of a fan but the big problem apart from drilling the correct holes etc... Would be getting hold of the correct cloth in the UK so I will think abut it..

It's not like we get loads of sunshine here in London to rot the foams that quickly!!

[mech986]

I'm not sure about grilles....I've never been much of a fan but the big problem apart from drilling the correct holes etc... Would be getting hold of the correct cloth in the UK so I will think abut it..

It's not like we get loads of sunshine here in London to rot the foams that quickly!!

http://www.ebay.com/itm/Beautiful-New-JBL-4425-Studio-Monitor-Grilles-Choose-From-Nine-Colors-/161766474612

you can likely find that also on UK Ebay if you use the same item number. It isn't so much the sunlight rot, it keeping fingers away from poking those new surrounds and the woofer's center dust cap. Helps with the WAF as well. There are reproduction grille pegs as well.

[Moko]

Some final pics of the finished speakers...sorry not the greatest quality.

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpssqofcf6b.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpssqofcf6b.jpeg.html)

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpsf245sgrl.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpsf245sgrl.jpeg.html)

http://i787.photobucket.com/albums/yy154/MokoMilk/JBL%204425/image_zpsii24aoaq.jpeg (http://s787.photobucket.com/user/MokoMilk/media/JBL%204425/image_zpsii24aoaq.jpeg.html)

A big thanks to all the people who helped me along the way to restore these great speakers, your knowledge and willingness to share that information has made this restoration virtually painless (well apart from my arm from all that polishing!!)

[Odd]

Nice job!

They look really good.

[dprice]

That went pretty quick! Nice work :D

[ARMED]

nice! i just got a set myself!!! rough frankenstein condition... im about to clean it up also!!

[Moko]

What do most folks here run the the High Frequency and Mid Frequency levels at on their speakers?

I guess it's largely room dependent but I just wondered if there was a general feeling that the bass needed turning down etc.

[Lee in Montreal]

What do most folks here run the the High Frequency and Mid Frequency levels at on their speakers?

I guess it's largely room dependent but I just wondered if there was a general feeling that the bass needed turning down etc.

Maybe it is the upper bass that is too upfront. Try plugging one of the two ducts. That shall lower the tuning frequency. You can also make both ducts longer.

You can also raise the boxes. 2 feet?

And these are free mods that are reversible ... ;-)

[johnlcnm]

What do most folks here run the the High Frequency and Mid Frequency levels at on their speakers?

I guess it's largely room dependent but I just wondered if there was a general feeling that the bass needed turning down etc.
,

I have had the same experience with the 4425s. Bloated base. Plus some issues with a lack of lower mid-range. The problem in the mid-range could be a crossover issue. I believe that Jerv, a forum member, designed a new crossover for these guys. If I get a chance, I will try to run down the link to his crossover and post it.

Regards

John

[johnlcnm]

Link to Jervs crossover: http://www.audioheritage.org/vbulletin/showthread.php?12431-Yet-another-4425-DIY&highlight=jervs+4425

He designed this from scratch as he did not have the original network. IMO, the original network does not get the mass rolloff EQ correct. I have always noticed a peak in the two to three K. range. A DSP can also correct for these anomalies including the bass issues. If you look at Jervs network he addresses the two to three K issue with two traps in his circuit. The 4.1uF cap compensates for that mass rolloff, but that needs to cease and desist in the 2-3K range where it is not needed. The original network uses a high resistance inductor as a cost effective means of deducting the boost in that 2-3K area. All my opinion without an in depth analysis. Maybe we will get a more accurate analysis by someone who has looked at and analyzed these issues with the 4425.

Regards,

John

[DavidF]

What do most folks here run the the High Frequency and Mid Frequency levels at on their speakers?

I guess it's largely room dependent but I just wondered if there was a general feeling that the bass needed turning down etc.

Are you listening to the systems as shown in the pictures (great work on the rehab, by the way)? The bass of the system is boundary dependent and you may have to move them out from the wall.

[Moko]

Sorry I think I may not have made myself clear enough....I'm happy with how the speakers sound in general but was just wondering what levels most users set the Mid and High Frequency controls?

Unfortunately in my room one speaker (the one in the photo) has to be very close to the wall, but luckily the other has a bit more room to breathe so the sound will always be a bit of a compromise.

At present I've no intention of changing the crossover but I did do the Troel Gravenson crossover in my pair of 4311's which did make them a much nicer speaker to listen too....so I won't rule it out forever.