Modified PB12
truckman: Doesn't look too bad. If you put some body filler (like bondo) on the seems and sanded it and painted it it'd be hard to tell that wasn't the way it came originally! And is that an ND310 (the JBL Northridge 10" Tower Speakers) I see next to it? If so...nice choice (lol also what I have). I'd offer to buy your old JBL amp but I have a feeling it might have a lot of life left in it. Where you boarded up the hole where the stock amp went, did you remove the plastic 'box'? And with the new amp did the sub enclosure size change much? Also, I didn't check yet but I'm guessing the enclosure is MDF with a veneer applied to it?
Also, I like the 3' cubic box idea. I've always wanted to build a custom enclosure, and I think I could make one that looked pretty neat. I don't know how well it would sound though lol. I am probably not going to try and build a new enclosure *yet* but am definitely going to do some research, I've already got a design idea in my head and since I'm in the right place it'd be neat to price it out and get some feedback.
Anyway, thanks for the input guys! Its been very helpful...I think my plan of action now is to order a few bits and pieces and try and replace them on the current amp, and if that doesn't work the plate amp looks like a good plan. And after the input I might skip the polyfil...looks like that's only really beneficial for a sealed enclosure anyway.
truckman: Doesn't look too bad. If you put some body filler (like bondo) on the seems and sanded it and painted it it'd be hard to tell that wasn't the way it came originally! And is that an ND310 (the JBL Northridge 10" Tower Speakers) I see next to it? If so...nice choice (lol also what I have). I'd offer to buy your old JBL amp but I have a feeling it might have a lot of life left in it. Where you boarded up the hole where the stock amp went, did you remove the plastic 'box'? And with the new amp did the sub enclosure size change much? Also, I didn't check yet but I'm guessing the enclosure is MDF with a veneer applied to it?
Also, I like the 3' cubic box idea. I've always wanted to build a custom enclosure, and I think I could make one that looked pretty neat. I don't know how well it would sound though lol. I am probably not going to try and build a new enclosure *yet* but am definitely going to do some research, I've already got a design idea in my head and since I'm in the right place it'd be neat to price it out and get some feedback.
Anyway, thanks for the input guys! Its been very helpful...I think my plan of action now is to order a few bits and pieces and try and replace them on the current amp, and if that doesn't work the plate amp looks like a good plan. And after the input I might skip the polyfil...looks like that's only really beneficial for a sealed enclosure anyway.
Re: Modified PB12
Also, I didn't check yet but I'm guessing the enclosure is MDF with a veneer applied to it?
Also, I like the 3' cubic box idea. I've always wanted to build a custom enclosure, and I think I could make one that looked pretty neat. I don't know how well it would sound though lol. I am probably not going to try and build a new enclosure *yet* but am definitely going to do some research, I've already got a design idea in my head and since I'm in the right place it'd be neat to price it out and get some feedback.
Anyway, thanks for the input guys! Its been very helpful...I think my plan of action now is to order a few bits and pieces and try and replace them on the current amp, and if that doesn't work the plate amp looks like a good plan. And after the input I might skip the polyfil...looks like that's only really beneficial for a sealed enclosure anyway. [/B][/QUOTE]
I dont think its a wood veneer its that vinyl stuff .
What I like about building a enclosure is you can build the cabinet to fit a certain location, I have one behind the TV one as a speaker stand and one in a fireplace (not to light but it was a location) .
Fixing the old amp is cheaper and hopefully it will last .
I do my research on WINISD it shows you what the speaker can do , tells you if you are wasting your time BEFORE you build a box .
Also, I didn't check yet but I'm guessing the enclosure is MDF with a veneer applied to it?
Also, I like the 3' cubic box idea. I've always wanted to build a custom enclosure, and I think I could make one that looked pretty neat. I don't know how well it would sound though lol. I am probably not going to try and build a new enclosure *yet* but am definitely going to do some research, I've already got a design idea in my head and since I'm in the right place it'd be neat to price it out and get some feedback.
Anyway, thanks for the input guys! Its been very helpful...I think my plan of action now is to order a few bits and pieces and try and replace them on the current amp, and if that doesn't work the plate amp looks like a good plan. And after the input I might skip the polyfil...looks like that's only really beneficial for a sealed enclosure anyway.
[/B][/QUOTE]I dont think its a wood veneer its that vinyl stuff .
What I like about building a enclosure is you can build the cabinet to fit a certain location, I have one behind the TV one as a speaker stand and one in a fireplace (not to light but it was a location) .
Fixing the old amp is cheaper and hopefully it will last .
I do my research on WINISD it shows you what the speaker can do , tells you if you are wasting your time BEFORE you build a box .
Re: Modified PB12
Those towers are actually MTX towers. Can't remember the model number off the top of my head and I'm at work right now. They have dual active 12" subs in each of them along with a mid and horn.WagonWheelsRX8 said:
I did take the plastic box out with the old amp so I suppose the enclosure size is increased a little as the new amp doesn't have an enclosure inside the box and doesn't take up as much internal room as the old one.
You are correct, the enclosure is mdf with some kind of veneer.
Keepin' This one alive
I just picked one of these JBL PB12s up. I opened up the s64ami module and stripped off the board to rebuild. Then I found this post. It has been a lot of help since I didn't get every value while breaking away the epoxy. I've got all the parts on an order and it will be cheap to rebuild the entire thing but I can't seem to find a good availability of the varactor diodes, 1N5140s. Is there any way I can replace them with something or a good place to get them? Thanks!
I just picked one of these JBL PB12s up. I opened up the s64ami module and stripped off the board to rebuild. Then I found this post. It has been a lot of help since I didn't get every value while breaking away the epoxy. I've got all the parts on an order and it will be cheap to rebuild the entire thing but I can't seem to find a good availability of the varactor diodes, 1N5140s. Is there any way I can replace them with something or a good place to get them? Thanks!
The diodes D8 and D9 are 1N4150 not 1N5140 and they are not varactor dodes. They are fast switching diodes. The schematic in the earlier post had the wrong part number in it. The originator of the schematic mentioned the error in a later post.
I'm getting a thumping and breaking up type sound. I was told the L1 inductor/choke was the cause.
Good morning. Sorry to upgrade an obvious lemon product, but I purchased one before I knew about this thread. Having read many of the posts I am wondering if any member would like to sell the 12" woofer to this system or if anyone is interested in the power amp/ circuit unit as mine sees to have blown the fuse? Thanks for reading my first post, and make me a deal..........thanks
my subwoofer is in great shape and the box is solid but with some scratches on them, the poweramp is fried and gone. If you are near Norfolk,Va or within 200 miles; we might arrange something: my email is timehascome444@Yahoo.com but after Thanksgiving it's going on Craigslist. let me know and I'll send a picture....
Hey everybody! New here. I too have fallen prey to the PB12 dilemma! Except, I bought mine, brand new over 10 years ago and never once had a problem with it.
It went out yesterday and with a bit of searching I found this site. I read the entire post and then noticed that it started way back! lol.
So, to my dismay I guess it's buy a new amp or new unit, I'm sad.
It went out yesterday and with a bit of searching I found this site. I read the entire post and then noticed that it started way back! lol.
So, to my dismay I guess it's buy a new amp or new unit, I'm sad.
i have an early model of the PB12 (made in canada) before they switched to a Mexican-made version. It has performed well for 11 years. Lately it pops and groans when turned on and it crackles and doesn't play well. I left it off for 2 months and decided to turn it on again today. After initially popping and groaning it is now playing close to normal (i think). After reading all the horror stories about the burnt power module, i am wondering if i should leave this alone or take it apart and see the condition of the board. Thoughts?
Wow... What a great thread with amazing knowledge and input by all!
Mid-thread, I was very hopeful that the uber technical among us had come up with a good solution and found a way forward with these subs/amps, but by the end it turned into an amplifier swap-out party, which makes me sad, but sounds like it may be the reality with this unit.
So, why am I chiming in? I too have a pb12 and, despite all the issues surrounding it, quite enjoy the sound and performance (largely due to what came before it for me, don't get me wrong, I know there are lots better subs out there). Having said that, mine has just started exhibiting some weirdness... Around 50% of the time, when its kicking in, it makes a strained squak/groan but then performs fine. I've also once noticed it go into standbye when I paused a movie briefly - with no 15 minute time out period. It had been playing fine before I paused it, and it continued fine when I resumed the movie. Odd.
Anyway, the later issue seems a one-off, more of a side note to the larger issue.
I enjoyed the thread immensely, but admittedly, didn't understand a whole lot of it. I'm wondering, can someone sum up a reasonable approach to extending the life of this unit? Some prescription for palliative care?
What would be the most effective upgrade to perform? Can someone suggest a list of the most likely components I should replace to keep my unit going strong?
I have a revision 2 unit.
Thanks to any technical guys/gals that can chime in!
Mid-thread, I was very hopeful that the uber technical among us had come up with a good solution and found a way forward with these subs/amps, but by the end it turned into an amplifier swap-out party,
which makes me sad, but sounds like it may be the reality with this unit.So, why am I chiming in? I too have a pb12 and, despite all the issues surrounding it, quite enjoy the sound and performance (largely due to what came before it for me, don't get me wrong, I know there are lots better subs out there). Having said that, mine has just started exhibiting some weirdness... Around 50% of the time, when its kicking in, it makes a strained squak/groan but then performs fine. I've also once noticed it go into standbye when I paused a movie briefly - with no 15 minute time out period. It had been playing fine before I paused it, and it continued fine when I resumed the movie. Odd.
Anyway, the later issue seems a one-off, more of a side note to the larger issue.
I enjoyed the thread immensely, but admittedly, didn't understand a whole lot of it. I'm wondering, can someone sum up a reasonable approach to extending the life of this unit? Some prescription for palliative care?
What would be the most effective upgrade to perform? Can someone suggest a list of the most likely components I should replace to keep my unit going strong?
I have a revision 2 unit.
Thanks to any technical guys/gals that can chime in!
I have a JBL Digital 12 that's roughly based on a similar S53 module.
I have found that the large power resistors (the largest resistors on the board) are way too close to the PCB. They get too hot and the PCB will 'burn' very slowly.
I saw this while doing a routine check-up and I had to hard-wire the PCB traces because they were damaged so badly...
This thing HAD to break, it wouldn't have survived another year. I'm so sad that this has to be a JBL product, considered a 'quality' brand.
I have found that the large power resistors (the largest resistors on the board) are way too close to the PCB. They get too hot and the PCB will 'burn' very slowly.
I saw this while doing a routine check-up and I had to hard-wire the PCB traces because they were damaged so badly...
This thing HAD to break, it wouldn't have survived another year. I'm so sad that this has to be a JBL product, considered a 'quality' brand.
Had you noticed any issues prior to that? Are you still going strong having replaced those resistors now?
I have bought the sub second hand. It worked good. I know the former owner never abused it, but I decided to check it anyway and that's when I found this out. So I don't know if there were any issues before I got it.
I do know the board was still stock, nothing was replaced or modded.
It's still going strong (about 6 months ago I replaced the resistors).
But it won't last forever this way. The PCB was burnt so badly I should have cut the burned pieces out and fill them with epoxy or something like that and redraw the traces. Unfortunately this was a 2-layer board and I don't have the skills to do that...
So I replaced the resistors with much larger ones and I kept them away from the PCB using spacers/straws.
Sooner or later, it's going to fail again.
It's not difficult to check if your board has similar problems: look for black areas on the pcb, like this. If the traces are already coming loose from the board, the damage is severe.
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When you say, it's going to fail again, do you mean it had failed outright before, or you just mean, it will get hot/burn again? was it at any point not working before you decided to replace the resistors?
You said you put much larger ones in - larger ones of the same value, or ones with a higher resistance?
thx.