JBL Performance Series

[Don C]

I've decided to make passive subwoofers using the cabinets. The woofer itself was not harmed by the amp failure. I've already pulled out the bad amplifier, and I'll use the back plate as a template to drill a piece of wood to close up the back of the box. It looks like taking the amp out will increase the internal volume from roughly 2.0 to 2.5 cu ft. It will still be too small, but at least its getting better. I'll need to retune the box, and I'm looking for help figuring out what is needed to keep the same port frequency with the higher box volume. I'm going to get more detailed dimensions, hopefully later tonight.

[Titanium Dome]

I've decided to make passive subwoofers using the cabinets. The woofer itself was not harmed by the amp failure. I've already pulled out the bad amplifier, and I'll use the back plate as a template to drill a piece of wood to close up the back of the box. It looks like taking the amp out will increase the internal volume from roughly 2.0 to 2.5 cu ft. It will still be too small, but at least its getting better. I'll need to retune the box, and I'm looking for help figuring out what is needed to keep the same port frequency with the higher box volume. I'm going to get more detailed dimensions, hopefully later tonight.

I'll be curious to see what suggestions you get. I think you're probably making a long term decision that all powered sub users face eventually

[rdgrimes]

Some PS nut should snap this up:
http://cgi.ebay.com/jbl-speaker-s4hc...ers_Subwoofers

No affiliation.

[Titanium Dome]

Some PS nut should snap this up:

Who you calling a nut?

[Don C]

Now I've figured the volumes more carefully and put the data into Winisd. I had the volumes wrong in my previous post. The amplifier module displaces .164 cu ft. Roughly. It doesn't make a lot of difference to the box tuning. The ports are 2X 2.5 inches by 12 inches length for both plots.

.

[Slare]

I'd sure hate to give up the 130Hz high-pass and bi-amp feature that these offer, but you could certainly use a different plate amp too and add your own high/low-pass filters for the PT800s.

Man, I hate reading these discussions because it makes nervous given I have four well-used PS1400's in service and one "spare".

I will say, that the 130Hz HP crossover is just a conventional passive unit that is contained in the PS1400 enclosure... it is not an electrical crossover in the PS1400 amp, which is what I was most nervous about trying to replicate.

So my thought has always been that if the PS1400 amplifiers start to fail, I would hopefully be able to find a slightly more compact amplifier which I could mount to an adapter plate that also had room for a set of binding posts to wire up to the crossover and thus up into the docked PT800 for minimal modification to the factory hardware.

I hope that it is not something I will have to deal with anytime soon... but one must be realistic in that these amps do have some level of fixed service life. I just hope mine are on the right end of the curve or die to some home owners insurable incident.

[tom1040]

Forgive me. I have a stupid question. Since I am unfamilar with the performance series...could someone take the plate amp from a L8400 to replace the defective ones in the performance series? I think the l8400 is 600 vs. 400 watts. Just 'throwing' that one out there.

[rdgrimes]

Forgive me. I have a stupid question. Since I am unfamilar with the performance series...could someone take the plate amp from a L8400 to replace the defective ones in the performance series? I think the l8400 is 600 vs. 400 watts. Just 'throwing' that one out there.

400W is ample power for the driver and enclosure. I doubt the L8400 amp would fit anyway.
There's loads of available plate amps around.

[Titanium Dome]

Forgive me. I have a stupid question. Since I am unfamilar with the performance series...could someone take the plate amp from a L8400 to replace the defective ones in the performance series? I think the l8400 is 600 vs. 400 watts. Just 'throwing' that one out there.

400W is ample power for the driver and enclosure. I doubt the L8400 amp would fit anyway.
There's loads of available plate amps around.

The PS1400 amp is unusually long and narrow. It has to fit between two bracing ribs inside the PS1400 enclosure. Any amp that is much wider than the stock unit simply will not fit unless someone FUBARs the enclosure by cutting out the braces.

Since all four of my PS1400 amps had to be rebuilt, I considered all the options and went with fixing the amps as the best option. Unfortunately, the gent who did the work got slashed in the Northridge Massacre, so I don't know how I'll handle it if they die again.

Likely it'll be to seal the enclosure and use external power, or sell them to one of you guys "as is."

[Slare]

Dome, any chance you could ask him about the subsonic and high pass rolloff behavior of the PS1400 amplifier?

The PT800 crossover is cake as it's a passive... but to get a 100% match to original behavior using an external amp you'd need to duplicate the PS1400 amp low pass crossover behavior and possible subsonic filter behavior. I know a bunch of different plate amps out there have much different characteristics without really flat response.

One get get pretty similar results with just about any decent plate amp or outboard amplifier. But if I ever do this I'd want to know exactly what was needed out of the sub amp to duplicate the OEM behavior. It'd be a good thing to try and archive it while the info is still somewhat fresh.

[Titanium Dome]

He's not in a real good mood right now. I'll see what I can glean, although someone smarter than me can read the tech materials and figure it out. We know lots about the driver.

http://www.audioheritage.org/vbullet...?11317-LE14H-3

[Titanium Dome]

And we know what happens when the signal first goes in.

[Robh3606]

Well if you can you might want to consider a larger box and just salvage the docking mechanics. Those boxes are too small to get the most lowend out of an LE-14H-3 as it is. If the amps do die you can always repower them in a larger box. If you are running with a good front end you should have enough bass management control to make things work or use the passive in the post above.

Rob

[rdgrimes]

Well if you can you might want to consider a larger box and just salvage the docking mechanics. Those boxes are too small to get the most lowend out of an LE-14H-3 as it is. If the amps do die you can always repower them in a larger box. If you are running with a good front end you should have enough bass management control to make things work or use the passive in the post above.

Rob

Like docking the PT800 to the bottom end of an Array 1400? Please do, sounds like a fine idea if not too tall.

I really doubt that having the OEM PS1400 amps repaired is such a big deal, and any competent shop should be able to do it. Hope I never have to find out, but I'll bet it's cheaper than the alternatives.

[Titanium Dome]

Like docking the PT800 to the bottom end of an Array 1400? Please do, sounds like a fine idea if not too tall.

I really doubt that having the OEM PS1400 amps repaired is such a big deal, and any competent shop should be able to do it. Hope I never have to find out, but I'll bet it's cheaper than the alternatives.

How much are you willing to bet?