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What happened to my speaker cab?!

rossta1

Member
Messages
204
I picked up an early '70's Fender 2x15 cab in decent condition and it had been working fine w/ my GenzBenz combo. Then I let a young, LOUD punk band record at my pad using my gear. At one point the bassist was kicking in the distortion/fuzz and then all of a sudden the sound is gone.

What happened?!

If the speakers were blown wouldn't I hear at least something? I'm hoping this is a amateur-level fix cause the sucker is HUGE and moving it is unfun to be sure. Anyone have any suggestions where I should start troubleshooting?

Thx in advance,
~ross
 

gumtown

Member
Messages
1,980
Depends on how it's wired, if the speakers are in parallel, I would not expect both to hav blown.
I guess you have already tried another amp/speaker to be sure the amp itself is O.K.

Does the cabnet have a fuse, if not, maybe a broken wire internally, either way, you will need to open the cab, probably by removing the speakers, or a back panel.
Do a continuity test across each driver.
 

Fly Guitars

Member
Messages
57
Yeah, the extreme vibrations may have just broken a connection somewhere. I've found that amps/cabs that I assumed were 'blown' were often actually shaken apart rather than anything electrical.
 

rossta1

Member
Messages
204
Yeah the amp itself is A-ok. I'll take the back off and look for a broken connection. And yeah those vibrations were extreme! Thanks guys.
 

walterw

Platinum Supporting Member
Messages
39,788
it's just as likely the speakers are blown.

too much volume and low end on old low-powered speakers, then a fuzz gets kicked on, could very easily kill one speaker; once dead, all that excess power now slams into the other speaker, quickly killing it too.

you need at least a 9V battery to see if they move, and a multimeter to check resistance to confirm.

(plug a new cable into the cab, and put the other cable end against the 9V, + to tip and - to sleeve; the speakers should jump forward.)

you might need to open the cab up and put the battery right against the terminals of each speaker to confirm if they're alive or dead.
 

Wag

Silver Supporting Member
Messages
481
I'm with Walter on this one. Odds are the speakers are blown.

I have two 70's era Fender cabs. 1 is a 2x12 and the other is a 2x15. Neither one had speakers that would stand up to heavy bass.

(Don't run you amp into this cab until you have it fixed......or you might be fixing the amp as well)
 
Messages
237
I used to have one of those cabs. When you pull the blown ones out (I would bet money they are toasted nicely) find a pair of 400-watt EV 15-L speakers and put em in. They happen to work great with that cabinet. You'll have bass that can be heard for a hundred miles around and they are practically unblowable (you can blow anything if you squarewave it hard enough, but most amps will go before those speakers will).

Sorry to hear and good luck.
 

MandolinFan

Member
Messages
172
I agree with the fella's; most likely, your speakers are crispy-critters.

Some crossovers have load fuses that will sometimes go first and save the speakers.
I'm kinda doubting an early Fender cab will have this feature.

If you ever use effects that vary your signal (especially in amplitude) I would recommend inserting some compression into your signal chain.
 

Rich_S

Member
Messages
433
I'm kinda doubting an early Fender cab will have this feature.

Especially since they don't have crossovers...

If the speakers are wired in series, then blowing one will open the circuit, and prevent the other one from blowing.

If they are in parallel, then blowing one will increase the amount of power going into the remaining good one, increasing the likelyhood that it will blow, too.

Damage can be done short of a full open-coil failure, too. Overheating speakers can soften the glue that holds them together, allowing the voice coil to slip out of alignment and start rubbing. Eventually, this could lead to complete failure.

It's best to open the cabinet up, separate the wiring, and test each driver individually. Test for an open coil with a battery or an ohm meter. Check for voice coil rub by gently pressing on the cone with your fingers just enough to slide the voice coil in and out and see if it makes a scraping noise.
 

rossta1

Member
Messages
204
So it turns out these speakers were not only blown but they were almost falling completely apart. 2 more questions for you kind, helpful & intelligent folks:
1. What should I do w/ these huge, ruined speakers. Magnets are always fun, right?! and...
2. Where would you guys advise one to shop for replacements? I like The Moar You Know's idea of some 400-watt EV 15-L speakers!

Thanks again everyone,
~rc

A653C6CC_zps186b9866.jpg
 

MandolinFan

Member
Messages
172
Especially since they don't have crossovers....

Brilliant. That's what I, basically, said...



One other thought I had: would repairing the speakers be worth the hassle?

Re-coning will remedy your issue. It's worth it, especially if those are the original speakers to the cab.

I just had the speakers from one of my Eden 2x10's re-coned and after break-in it sounds better than ever.

Depending on your area, re-coning should be in the range of $50-70 per speaker.
 

SarasotaSlim

Member
Messages
1,592
Those old D series JBLs are gonna give your wallet sticker shock when you go to get them re-coned. Go to a service that will use JBL parts. You can't get the original D kits anymore but the good news is the newer E kits are available and will sound better and last forever unlike the old paper surround on yours - the paper eventually gives up with time and those things were made in the 60' ?? so it was time - the punkers just pushed them over the edge for you. If you had opened the box before they ever plugged in I'm sure you would have seen the surround was already going on them. You could always offer them to the cork sniffers here and let them re-cone them. If they were 12's I'd be at your door already.
 

SarasotaSlim

Member
Messages
1,592
Brilliant. That's what I, basically, said...





Re-coning will remedy your issue. It's worth it, especially if those are the original speakers to the cab.

I just had the speakers from one of my Eden 2x10's re-coned and after break-in it sounds better than ever.

Depending on your area, re-coning should be in the range of $50-70 per speaker.

not for JBLs - try $200++ each
 

MandolinFan

Member
Messages
172
not for JBLs - try $200++ each

Seriously?!?!?

Yowza! I'd have to reconsider on a recone for that kinda cash.

I'd probably slap them back in the cab, as is, and sell it off for whatever you can get from a "Cork Sniffer". Then turn around and get a new cab with the cash.
 

SarasotaSlim

Member
Messages
1,592
You could always offer the blown baskets on FleaBay - they should be worth $50 - 100 each as is depending on how bad somebody wants them. The bad news is that there are still plenty of these things in various condition still floating around out there all over the place. The good news is that these are Dick Dale type favorites and they were also used in SRV's Vibroverb (might have been an E) so there are people out there that like them. Again - if they were 12's all of TGP would be knocking on your door to get the baskets.
 
Messages
237
Oh, that sucks. The JBLs were classics in the day for bass.

These could be an expensive recone. However, might be worth it. Call up Orange County Speaker Repair (best in the world) and find out how much it will be instead of letting us armchair quarterbacks, who don't know, stampede you into a course of action. I think both Parts Express and Mojotone recone speakers, although with old awesome speakers like this, I wouldn't send them to Parts Express. They haven't been doing it long enough to have a track record I would trust vintage items to.

So, you have some interesting options. One would be to get these reconed. They are awesome speakers, but they also have a certain tone. Midrangy. Think of the bass tone on Rush's "Moving Pictures". That's JBL D-series all the way in a hard rock context.

The old school bass guys will love them. Some of the vintage guitar crowd like 'em too. However, if you're having kids come in and trying to play EMG 5-strings through them, drop tuning, all that stuff that

GET OFF MY LAWN

the youngsters like, the kids will invariably pump too much bass through them and either blow them or shorten their life considerably.

Option 2: If this is a practice studio cab or recording cab that youngsters are going to use, you can spend a unnecessarily large amount of money and get the EVs I suggested (an option that would have been a good idea back in 1987, maybe not so much today, although they do sound great in that cab) or head over to Parts Express and grab a pair of Eminence 15" speakers. The Neo looks interesting and weighs little, something that as I get to the end of my forties becomes a very attractive proposition, especially when we're talking a 2x15 cabinet. The Legend CB158 weighs more, is the generic 15" bass guitar speaker of choice, and as an added bonus they are cheap. This is probably what I'd put in there, I'd have the JBLs reconed and sell them, I don't like the midrange-heavy tone that they have.

ETA: avoid Celestion bass speakers.
 
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Wag

Silver Supporting Member
Messages
481
If for some reason you are looking for yet ANOTHER opinion.... (or two)

1. If you got some extra cash I would get them fixed, just 'cause they are JBL's. If you don't want to repair them, don't destroy them. There is someone out there that will take (buy?) them. The vintage factor will come into play.

2. If you DO get them repaired, you STILL need to replace the speakers if you plan to continue using this cab with a bass amp. I personally wouldn't use the JBL's for anything but guitar.

These cabs really are not well suited to bass IMO (and I say that as someone who used mine for bass. I even gigged with them for a time!) But for home use, you put some some speakers in there that will handle the bottom end and they will thump well enough. I don't have any suggestions for a replacement speaker other than to say that I agree with the guy that said Celestions are probably not the best choice (I think that is what I have in both my cabs right now. They are OK, but are better suited to my guitar amps). I do know where you can get some advice on bass speakers and speaker cabs from VERY knowledgeable persons but don't know the policy here for posting links. If you want it, PM me and I can point you in that direction.

Good luck!
 




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