As a christmas present to me, mom said that me and the siblings don't have to pay rent this month. So I instantly splurged and went to the semi large car audio chain store
and scored me one of these bad puppies as per my new system plan.....
http://www.crutchfield.com/App/Product/Item/Main.aspx?g=120&i=109GTO754&c=3&tp=115
But it wasnt from Crutch....my buddy got me a slightly used floor model, and cut me a killer deal at 160 bucks....
Unfortunately this didn't last, I hooked her up and didn't quite have it dailed in right, and after testing it for a few, was certainly dissapointed to see it going in and out of protect mode. I left it alone, came back the next morning and it worked for a while, same thing. Called my buddy, he told me to take it to the store in my city, (50 mile trip to get the price, but all the service can be done here) to get it bench tested, and the replaced it on the spot....with another floor model.
Hooked it up, same thing, except this one was messed up the second it was hooked up.
Now im a bit spooked......He has ordered another one since this amp is being discontinued, but it wont be in for a few days. He says that he is "hoping" for a brand new unit, and all of this leaves me worried.
Now to some posible causes in the amp failure
Ground from circuit boards was dissconnected first?
My Power line being 8AWG in as opposed to the 4 on the terminal of the amp? Keeping in mind, that it was connected the same way in their circuit boards, if not with smaller wire.
I am 95 percent certain that my Power line is unbroken and short free, as I have never blown a fuse but once when my sister had a bad incedent with the door, and am confident another fuse was blown.
Same with the speaker wire. Short in length, and sompletely free of ant fraying.
When connecting the amp, I connected Ground, remote then power. My amp cable fuse was disconnected, but my H/U wire still had a fuse in it. It was turned off though. I used two 4 ohm 10 inch subs, hooked up bridged to each channel. One sub was initally out of phase, but corrected in minutes.
My install is definitely a bit messy, but everything is hooked up right. My upper range amp and H/U still work flawlessly, and I am stumped at the cause of death of these amps, and am worried the results of what will happened to anf future amp that could find it's way in. This is really got me with a sore attitude towards an amp I have been dreaming of for some time now, and got me paraniod that something in my install is so fualty to cause the death of an amp. I will try hooking up my old nasty sub amp, and see what the results are......
Any input would be great. This has definitely shot a hole in my initial system plan.
Replies (19)
trunkisloud on 12/5/2007 21:34:04
man you think you may have some improper ohmage goin to the amp from the subs?? are they svc or dvc subs???....ive seen a many amp crash due to this problem...but not usually right away.
ttocs on 12/6/2007 00:54:13
I had a bad first impression with jbl years ago and I have not been able to wash that taste out of my mouth since. I know there are alot of jbl fans on here but I can't help it. Over 10 years ago(long time!) our rep came in with one of the first 1000 watt 1 ohm amps that he was just gleaming about. We trouble shot that amp for 15 mins before we tested it as bad on the bench. He was terrible embarrased and brought another one out of the box to use and we were starting to question our sound board since that one had nothing either.
Sometimes they just have a bad run on a certain line. I remember having two alpine amps bad out of the box from the same line, it was the only two I have ever seen but on the same day it makes you start to wonder. If I had not insted so many alpine I would probably have the same taste in my mouth with them, everybody has a bad day right?
Victor on 12/6/2007 01:37:46
have seen something like this happen to the JBL CS series amps.....
SQLThump on 12/6/2007 02:57:42
Yeah, everybody has bad days, but both of these amps suppossedly worked fine on their circuit board, and went kaput upon entrance of the ghteeo hoopty bucket. Whats worse, is all should be normal for this amp. Bridged, powering a pair of 4 ohm subs, gains turned waaaaay down since it makes more than twice the power my subs can handle, crossover at the lowest point, and absolutely no bass boost. I tried it a little with tying the HP
I feel the nasty taste ttocs, as I have a major one against Rockford Fsogate, due to their questionable subwoofer quality in the days when I got into car audio. But JBL is like one of my favorite brands, made by Harmon International, who makes more stuff I like, make the baddest Live audio rigs, and many great home and car audio products products, a few of which I have owned in the past, of which is a two channel I run currently for my front stage.
I messed with it some more, and as long as I keep H/u signal waay low, and everything all the way down on the amp, I can almost get some low end with my tunes.
It gets replaced "Best case on Friday, worst case on Monday" and It damn well be a working new in box amp, or I'm taking my money back. I cannot use the proper words here on CK to express my anger......but here it goes censored
I will take my $160 to go whatever communist nation my amp is built in, and personally find out the factory and worker that had the "bad day" and made my amps, and club the poor smucks lights out for giving JBL a bad name! I rep JBL For Life son, and this ain't gonna fly!!!!!!
Now that thats out of my system.....
I seroiusly in my life have never spent this much money on one audio component in my life, and have built a system on half that money before, and almost wish I would have went to the pawnshop to get a new amp.
swez on 12/8/2007 11:52:11
Hum, it's possible that this series of amps had a problem during assy, bad parts installed or another freakish demon resides within? But I don't think so...
If it worked fine on the demo board at the store, then I would begin to look at several independent things in your install before rampaging back to any store for an exchange or refund.
For some knawing reason, power to this amp would be my first place to check. "Is this amp getting enough power, (Voltage & Current) to operate properly?" That means testing the input side voltage of the amp with a DC voltmeter. We're looking for a solid 13.5 volts when the engine is running and all basic devices are operating normally. If that's not happening, need to figure out why.
The 2nd test would be removing one RCA input and disconnect one sub from said bridged channel pairings. (Say the front channel wiring set) Now, test the rear channel amp and sub to see if the amp remains stable as you monitor DC input voltage to the amp. My gut says it will be fine.
If that pans out OK, then test only the front channel and sub to see how the amp responds. Run the same tests as before and see if the amp remains stable.
If during either test the amp gets quirky, the sub connected to that channel would be my next logical step... swap the sub that seems to be troublesome for the known good one. If that channel works out OK now, you have a failing sub on your hands. If both subs are OK and both channels are OK when run independently, then the amp is not getting enough input side power to run both F & B channels at the same time. (Power starvation to this amp is my educated guess here)
Finally, if all test show this amp is not getting adequate power to run both bridged channels properly, (And both subs are good) the obvious solution would be to use a less power hungry Class D amp.
Here, the JBL Grand Touring Series GTO301.1 II would be a nice choice. It puts out almost 300 Wrms @ 2 ohms and draws about 27 amperes of current. Nice power, efficiency is very good and the features are very adequate for SQL needs.
This 4 channel amp is indeed stronger and wastes a lot of power due to heat. It's not really designed for sub use and the power draw is probably higher than your present electrical system can support. (Hense, it's rebelling) The amp is in a real sense saying... "Feed me a lot more power or I'll go on strike".
Why dor I say this? Well, a while back a buddy from back east came out for an install. He had the 6 channel version of this amp. (Acura Integra I believe) We installed new front comps, rear coaxials and just for fun, I tossed in a 4 ohm sub on the 5th channel. (JBL Grand Touring Series GTO755.6 II)
Once all was connected and dialed in, this amp performed very well in all ways. Clean power, good sub performance and the package was very robust in all ways. We were both very impressed with the whole install and he said... "Wow... this is much better than I had expected from the results I was stumbing through before".
Once again, the old addage applied... "In skilled hands, the install is 80% of the results". No, am not patting myself on the back here at all. The customer/buddy did that just fine. However, we both learned as we went along and even with a few minor detours, we came to a very
positive outcome. The smile on his face when we got his I-Pod interface and menus right, said it all. (Group high 5's were the payoff) Yet another happy camper headed down the road in Mobile audio bliss.
He could not use the sub at this point as he needed the cargo space for his other gear and such. But just trying the sub was well worth the time spent. When the time is right, he'll add a sub later.
OK, run your tests as noted and see what the results actually are. My bet is this amp is just too power hungry for the electrical system in this bucket for now. If that proves correct, you know the next steps.
Swez
SQLThump on 12/8/2007 15:46:04
Well, I have tried pretty much every thing I can think of, and the only thing left to try is hooking up the old amp. I have checked input voltage and it reads 13.7 with EVERYTHING on. With my old sub amp, the lowest it would drop was 12.9 when the bass was dropping as hard as possible. I looked up the instruction manual, and it will malfunction only if input voltage drops below 9 volts. So that removes that from the list.
My subs are good. I did not have a different sub available to test, so I dragged them into the house, and they both worked fine. My home theater would have shut off right away if there was a short in the subs. so scratch that.
I have tried every channel, whether bridged or not. Nothing will work here. tried disconnecting A and B channels, and leaving the other connected, still nothing. I have tried running it on HP, LP, with a variety of crossover settings, still nothing. It just won't work.
The only way I have been able to get any output whatsoever is by turning gain all the way down,sub output all tyhe way down. Fader all to the front, and H/U volume almost to the normal setting I use, and I can almost get some low end out of the amp.
I guess in my previous reant I could have better stated that I bought this amp from my freind who manages a shop, who i have known since middle school, and he cut me a killer deal on this amp. Since I am a freind, he has pulled ome strings, and a New amp is currently en-route from Texas, and will arrive in my town here sometime next week. It WILL be new in a box, and hopefully all will be well. I am going to hook up the old amp today to make sure everything else is kosher.
P.S. Swez, I checked every little thing imaginable in my system befroe posting, and I am completely stump on what tyhe hell is going on here. At this point, I am beginning to suspect some problem eith the H/U, as I have heard about them causing effects like this. My sister has a different deck I coukld check out, and I may try this. Anyway, iI'm gonna drag myself outside in the snow right now to check on this old amp. Lets hope all is well.....
swez on 12/8/2007 17:33:08
Interesting set of facts here SQL. Knowing all that, does point back to the amp itself.
Having low output and the protect circuits cycling in and out, points to internal amp guts problems. That might mean a few blown power transistors a few out of spec capacitors or a damaged power suppy system.
Anyway, all that and a $1.25 will get us a cup o COFFEE or a bag o chips. Here's to hoping the new amp works and gets the job done. Frankly, a Class D amp would be in order here, if your buddy can make a good one land in your lap?
Swez
PS Class D amps are fairly simple voltage multipliers and do that job very well. A well designed amp is reliable, robust and very efficient as well. (Less parts, but more robust ones, get the job done in this scenario)
SQLThump on 12/8/2007 21:34:24
The new (kind of good) news............
Hooked up the old amp, and it was the same problem, but on half the scale. Consiferdng it all worked fine, I went to the trunk to find one of my subs sounding completely devastated, and I find this funny as all seemed up to spec when I removed the subs from their boxes and inspected them. Guess it's time to pull some dustcaps and see how ugly these puppies look inside of them....
After hooking up the old amp, I put the new one back up to power, and remembered I had one good 8 inch sub in a dual bandpass box with a blown sub in the other chamber! VIOLA! A working speaker that doesnt involve disconnecting anything from the home theater.
Took those Puppies outside, and....It works!!!! Everything Works!!! Victory!!!!........except I don't have any working subs now, and a replacement is on the way from Texas. Doh!!! Now how to deal with both of these situations is sucking, especially since my trusty salesman is like my best freind, and I feel like a complete jackass right now...
So I decided to make a learning expeirence....How long would it take this amp to fry a low quality sub in a way mismatched box, with wattage approaching the rated 284 watts, firing in to this poor little 6 ohm devil.........
In literally a matter of seconds, with H/U volume at a healthy 20, and the gain around three quarters, this sub began to make a real nasty smell. a few more later, smoke was billowing out of the sound port, and it didn't stop until a few minutes after I ran iside and showed my brother and roomate. This guy was smoking like crazy! Cooked!
So the amp, with utmost confidence, definitely works. I still hhave a very small idea of how good it can sound, but hopefully new subs will be coming soon.
As for getting a Class D, I need this much power to be available to two seperate channels at 4 ohms. We were planning to run the upper bass drivers with the front channels, and the Dayton 15" sub on the rears, with the components on the amp I already have. Or if the amp I have proves works for the upper bass. It has it's own malfunction that made it not want to work with these subs, which I am wondering isn't the fault of those subs as well...
In either case, I am stoked to have the amp as per my original system plan, but totally bummed that I now have no bumps in the ride...........
swez on 12/9/2007 11:35:20
That is good news and yes, a "going bad" sub would indeed cause a good amp to sound bad or go into protect mode. (Mentioned that before did I not?)
It looks like some better subs are in order and soon huh? Now that the mid/highs are in place and doing OK, a pair of low budget Infinity Ref subs would be great on that new 4 channel. These are available in 4 ohm SVC's and 2+2 or 4+4 DVC coils. (300/350 Wrms respectively)
Some careful shopping would net a very low price too.
jamesp on 12/9/2007 16:24:45
Check out this link, Infinity Kappa's dual 2 or 4 Ohm for $73.85 ea. Refrence 12" same deal at $73.85 The VQ's are $134.85.
This is the best price on the Kappa's I have found. Not sure about the Refrence because I have not been pricing them..
Refrence shipping is $22.50 for 1 a pair may be a bit less ...
http://gallery.vendio.com/view/grandelectronics/ebay/index.html
SQLThump on 12/11/2007 01:16:20
I haven't built the components yet.......I decided the sub amp was the weakest link, and thought I could use the old subs with it......obviously those ghetto little guys weren't up to the task.
Swez, I did do a test of the subs, on my home theater, if a shorted speaker was ever hooked up before, it tripped a breaker, and it would shut off within seconds. All seemed normal, they sounded, looked and smelled OK, and I figured all was up to spec.
Lately my 5.1 reciever has been having some really strange, but hardly significant quirks. Just little stuff, like the sub out not making voltage if the unit is muted when it is turned off, an odd grounding problem a while back, and just today, static coming from the speakers. Odd stuff, but simply turning on and off the reciever corrects it. I can't complain. It was a gift horse anyway.
So what to do for subs now? I could go out and get some References, but this is contradictory to reason I bought this amp. My original plan was to power the comps I plan to build with the front channels of the GTO amp, a Dayton 15" for deep bass on the rear channel, and a pair of high effiecency 8's or 10's for upper bass, running on the JBL LC-A75.2 that I currently use for my front stage. I think I still want to stick to the original script here, and go with the Dayton 15"
A link to this sub...
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-560
The price is definitely right, and perfect for my goals and this amp. Hopefully I will have the extra dough to have 'er sent out next Monday.
As for the upper bass drivers, I may need to wait it out a bit longer, as I haven't decidet what drivers to use quite yet. We'll see about this in the future.
As for the front stage, I was going to get the parts to put them together after I replaced this amp, but I need bass now.......Rolling without it has definitely made me appreciete how good the little ghetto 20W Alpine 5.25's sound when there up to a loafing 75W JBL amp.
And at least I'm not totally screwed getting my bass fix, my home theater got's some mean 15" tower speakers that I use onlt for subs. Not the deepest bass, but everything above the 50hz rolloff is insane.
Just need to be patient, bide my time, and get everything put together. The Dayton is around the same price as the Reference, and I think it were yeild better results than the Infinity unit. We will see what I will score in a few weeks...
swez on 12/11/2007 02:51:40
OK, I remember that plan now and it was good then and still a good one now. The key is to stick to a good plan and avoid knee-jerk reactions as best as possible.
It appears this sub will do very well in a 1.5 cf sealed and has better than average eff too. The cabin gain will also help in the 50-70 Hz range and it also has a nice roll off curve for MB if you wished to use it as an extended range subwoofer/MB driver. (35 - 250 Hz.) Heck, this woofer could eliminate the need for separate MB speakers and amp with good EQ/LPF control. Only one way to find out... try a few things when you are able.
Swez
SQLThump on 12/11/2007 03:11:39
Actually, I was more of hoping to use it for more of an ultra deep bass driver, to cover around 60hz and below, and use the 10's or 8's for 60-200hz.
I know we talked about it earlier, but besides enclosure size, what would be some drawbacks to using an 18" version of the same woofer here? I understand it may be impractical, but the raw surface area makes me inclined to think it can put me on the path of having the absolute deepest bass possible in a midsize hoopty-bucket. I really don't care about trunk space, as long as I can wedge this muther in there.
I am having major problems deciding what to do for the upper range now. I am thinking of going crazy and putting some 10"s in the door, but I would need something with a slim profile, good performance, a pretty small enclosure requirement and most importantly, cheap.
Also wondering how much power loss I would be dealing with if an 8 ohm load was presented to the amp. I have seen a few 8 ohm drivers catching my eye, but am curious whether or not I will be able to extract enough power from the amp to make them hit.
Is there any other good websites besides Parts Express that offer good prices on some cheap drivers? I haven't found much yet.
swez on 12/12/2007 03:36:16
An 8 ohm driver will get 1/2 the wattage the amp can deliver at 4 ohms. That's about -3dB in terms of SPL differences.
PE is one of the best for the price. Madison Sound is another site for raw speakers, but they tend to be a lot more expensive too.
Going to an 18" sub cuts 2 ways...
1. Often need a very large box
2. Home gear is usually low power and Pro Audio is often 8 ohms and high power and cost
OK, I remember now that you did want a sub for the deep lows only and then use MB/MR/TW to fill in the rest. Most good quality 6.5 - 8" MB drivers will do 60 Hz and up just fine. The trick is mounting them into the doors so they look OK and don't bind.
Swez
SQLThump on 12/12/2007 16:48:50
Alright, glad to see we are on the same page again. I was thinking an 8 ohmer wouldn't recieve such a bad power cut since the amp doesn't double in power at 2 ohms, but rather a 40% increase. I figured going to 8 ohms wouldn't be such a steep penalty.
I will have to check out this Madison sound. I want to check out the fullest range of drivers possible before I make my choice.
The 18" sub I have in mind is pretty much the same Dayton Quattro as the 15" I've been looking at, but just an 18" model.
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=295-475&CFID=548036&CFTOKEN=68196667
Same power handling and ohmage, but an extra $10 dollars per inch of cone area. A price I would be willing to pay, as long as the Hoopty can have one of these stuffed in the back somehow......I can't keep this sub off my mind. I would probably be the only person in Northern Colorado knockin' an 18"
I still want to run midbass drivers, but I did a tally on the price of the components we designed, which was $192.20 without shipping, and think this may be going on hold for a while. The same buddy offered to sell me his old Infinity speakers from his wrecked Camry.
With 5.25 components for the front, and 6x8 coaxials for the rear, and a set of 14 inch studded snow tires, everything in this package is the same size I need, and he is offering me this at the low-low price of $160. I have heard the system in his old ride, and it really screamed, and the snows are virtually brand new. I really don't want the 6x8's as I don't want to use rear fill, but I'll probably bust them out as house speakers or something. Much more for less money, so I think I am going to go for it.......
Having trouble deciding what to do for midbass drivers though. I want everything below 150hz to sound like boomy sub bass, and cant decide what drivers to use. Is Goldwood a decent brand for cheap midbass drivers? there is quite a few models that would seem to offer the versitility I would require.
As for the door mount, I was thinking of building MDF enclosures for whatever driver I decide on, and then from there cut the door panels to fit them in there, attach them to the door somehow, and reupholster the door panel. As long as the enclosure doesn't stick too far out from the original door profile, this could work.....
swez on 12/13/2007 00:14:38
The Goldwood drivers are not bad if you amp them. Some have very low eff ratings and are available in 4 or 8 ohm units. They can take some good power too. (But need power to get the most from them)
The 18" vs the 15" Dayton, I don't see the benefit of this 18" sub for car use. A sealed or ported box for the 18" would be very large... make that huge, and not receommended.
Swez
SQLThump on 12/13/2007 04:24:44
Right on on the Goldwoods. I was thinking they may be alright, but wasn't sure, so I figured I would run it by good Old Man Audio first. They seem right for the price, and would make some decent low end until I get the ultimate sub bass. Now to decide what size.
The 8" model
http://www.partsexpress.com/pe/showdetl.cfm?Partnumber=290-357&vReviewShow=1&vReviewRand=820823#reviews
The 10" model
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-362
I was eyeing these because they were matching up nicely with the stereo wattage of the GTO, and could run them off the front channels to provide that deep midbass I want to compliment the Dayton 15".
But I am not too sure of the enclosure requirements of these drivers, which makes me second guess their ability foor door mount use. I think I may need to look around some more on these drivers.
I will take your word on the 18, but gotta ask one more question....
Would it make a good house sub to complement 50hz and below in the H/T? My 15's can make pound above that, but nothing super deep. how big of an enclosure would this puppy need for the crib?
swez on 12/13/2007 06:04:41
Used a pair of the Goldwods as replacement door speaks in my deceased Buick and they did well, but needed more power is all. Off the HU, they sounded good for range, but about -6dB lower than the stock rear speakers. (solid amp required) It was like this one, but no AV shielding:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-374
That 8" looks good down to 60 Hz, (F3) and still a solid 87dB at 2.83 volts. It peaks to 89.5 dB between 100 -150 Hz. and still solid above and belwo peak points. (Not a bad choice)
The 18" would make a nice HT sub. To get the correct box parameters, need a program to plug in the T/S parameters and plot it out like Ash does on his Pro Box design program. (Just looking at the Vas number told me this sub would like a very large box)
Swez
SQLThump on 12/14/2007 04:01:36
Where are you getting the response plots for the Goldwood? I haven't been able to get them.
Before I make a descision here, I need to find out how big of enclosures these 8's will need to make sure they are suitable for some sort of door mount......and hopefully one that doesn't involve some form of adhesive bonding strips.......
I will ask my sister if I can download WiniSD on her comp so I can crunch these numbers. I have been waiting for some time to put it on the POS comp I have been trying to peice together for some time now to work but to no avail.....
Maybe the Dyaton 18" will find a home then.......after my Bucket is finished.
and scored me one of these bad puppies as per my new system plan.....
http://www.crutchfield.com/App/Product/Item/Main.aspx?g=120&i=109GTO754&c=3&tp=115
But it wasnt from Crutch....my buddy got me a slightly used floor model, and cut me a killer deal at 160 bucks....
Unfortunately this didn't last, I hooked her up and didn't quite have it dailed in right, and after testing it for a few, was certainly dissapointed to see it going in and out of protect mode. I left it alone, came back the next morning and it worked for a while, same thing. Called my buddy, he told me to take it to the store in my city, (50 mile trip to get the price, but all the service can be done here) to get it bench tested, and the replaced it on the spot....with another floor model.
Hooked it up, same thing, except this one was messed up the second it was hooked up.
Now im a bit spooked......He has ordered another one since this amp is being discontinued, but it wont be in for a few days. He says that he is "hoping" for a brand new unit, and all of this leaves me worried.
Now to some posible causes in the amp failure
Ground from circuit boards was dissconnected first?
My Power line being 8AWG in as opposed to the 4 on the terminal of the amp? Keeping in mind, that it was connected the same way in their circuit boards, if not with smaller wire.
I am 95 percent certain that my Power line is unbroken and short free, as I have never blown a fuse but once when my sister had a bad incedent with the door, and am confident another fuse was blown.
Same with the speaker wire. Short in length, and sompletely free of ant fraying.
When connecting the amp, I connected Ground, remote then power. My amp cable fuse was disconnected, but my H/U wire still had a fuse in it. It was turned off though. I used two 4 ohm 10 inch subs, hooked up bridged to each channel. One sub was initally out of phase, but corrected in minutes.
My install is definitely a bit messy, but everything is hooked up right. My upper range amp and H/U still work flawlessly, and I am stumped at the cause of death of these amps, and am worried the results of what will happened to anf future amp that could find it's way in. This is really got me with a sore attitude towards an amp I have been dreaming of for some time now, and got me paraniod that something in my install is so fualty to cause the death of an amp. I will try hooking up my old nasty sub amp, and see what the results are......
Any input would be great. This has definitely shot a hole in my initial system plan.
Replies (19)
trunkisloud on 12/5/2007 21:34:04
man you think you may have some improper ohmage goin to the amp from the subs?? are they svc or dvc subs???....ive seen a many amp crash due to this problem...but not usually right away.
ttocs on 12/6/2007 00:54:13
I had a bad first impression with jbl years ago and I have not been able to wash that taste out of my mouth since. I know there are alot of jbl fans on here but I can't help it. Over 10 years ago(long time!) our rep came in with one of the first 1000 watt 1 ohm amps that he was just gleaming about. We trouble shot that amp for 15 mins before we tested it as bad on the bench. He was terrible embarrased and brought another one out of the box to use and we were starting to question our sound board since that one had nothing either.
Sometimes they just have a bad run on a certain line. I remember having two alpine amps bad out of the box from the same line, it was the only two I have ever seen but on the same day it makes you start to wonder. If I had not insted so many alpine I would probably have the same taste in my mouth with them, everybody has a bad day right?
Victor on 12/6/2007 01:37:46
have seen something like this happen to the JBL CS series amps.....
SQLThump on 12/6/2007 02:57:42
Yeah, everybody has bad days, but both of these amps suppossedly worked fine on their circuit board, and went kaput upon entrance of the ghteeo hoopty bucket. Whats worse, is all should be normal for this amp. Bridged, powering a pair of 4 ohm subs, gains turned waaaaay down since it makes more than twice the power my subs can handle, crossover at the lowest point, and absolutely no bass boost. I tried it a little with tying the HP
I feel the nasty taste ttocs, as I have a major one against Rockford Fsogate, due to their questionable subwoofer quality in the days when I got into car audio. But JBL is like one of my favorite brands, made by Harmon International, who makes more stuff I like, make the baddest Live audio rigs, and many great home and car audio products products, a few of which I have owned in the past, of which is a two channel I run currently for my front stage.
I messed with it some more, and as long as I keep H/u signal waay low, and everything all the way down on the amp, I can almost get some low end with my tunes.
It gets replaced "Best case on Friday, worst case on Monday" and It damn well be a working new in box amp, or I'm taking my money back. I cannot use the proper words here on CK to express my anger......but here it goes censored
I will take my $160 to go whatever communist nation my amp is built in, and personally find out the factory and worker that had the "bad day" and made my amps, and club the poor smucks lights out for giving JBL a bad name! I rep JBL For Life son, and this ain't gonna fly!!!!!!
Now that thats out of my system.....
I seroiusly in my life have never spent this much money on one audio component in my life, and have built a system on half that money before, and almost wish I would have went to the pawnshop to get a new amp.
swez on 12/8/2007 11:52:11
Hum, it's possible that this series of amps had a problem during assy, bad parts installed or another freakish demon resides within? But I don't think so...
If it worked fine on the demo board at the store, then I would begin to look at several independent things in your install before rampaging back to any store for an exchange or refund.
For some knawing reason, power to this amp would be my first place to check. "Is this amp getting enough power, (Voltage & Current) to operate properly?" That means testing the input side voltage of the amp with a DC voltmeter. We're looking for a solid 13.5 volts when the engine is running and all basic devices are operating normally. If that's not happening, need to figure out why.
The 2nd test would be removing one RCA input and disconnect one sub from said bridged channel pairings. (Say the front channel wiring set) Now, test the rear channel amp and sub to see if the amp remains stable as you monitor DC input voltage to the amp. My gut says it will be fine.
If that pans out OK, then test only the front channel and sub to see how the amp responds. Run the same tests as before and see if the amp remains stable.
If during either test the amp gets quirky, the sub connected to that channel would be my next logical step... swap the sub that seems to be troublesome for the known good one. If that channel works out OK now, you have a failing sub on your hands. If both subs are OK and both channels are OK when run independently, then the amp is not getting enough input side power to run both F & B channels at the same time. (Power starvation to this amp is my educated guess here)
Finally, if all test show this amp is not getting adequate power to run both bridged channels properly, (And both subs are good) the obvious solution would be to use a less power hungry Class D amp.
Here, the JBL Grand Touring Series GTO301.1 II would be a nice choice. It puts out almost 300 Wrms @ 2 ohms and draws about 27 amperes of current. Nice power, efficiency is very good and the features are very adequate for SQL needs.
This 4 channel amp is indeed stronger and wastes a lot of power due to heat. It's not really designed for sub use and the power draw is probably higher than your present electrical system can support. (Hense, it's rebelling) The amp is in a real sense saying... "Feed me a lot more power or I'll go on strike".
Why dor I say this? Well, a while back a buddy from back east came out for an install. He had the 6 channel version of this amp. (Acura Integra I believe) We installed new front comps, rear coaxials and just for fun, I tossed in a 4 ohm sub on the 5th channel. (JBL Grand Touring Series GTO755.6 II)
Once all was connected and dialed in, this amp performed very well in all ways. Clean power, good sub performance and the package was very robust in all ways. We were both very impressed with the whole install and he said... "Wow... this is much better than I had expected from the results I was stumbing through before".
Once again, the old addage applied... "In skilled hands, the install is 80% of the results". No, am not patting myself on the back here at all. The customer/buddy did that just fine. However, we both learned as we went along and even with a few minor detours, we came to a very
positive outcome. The smile on his face when we got his I-Pod interface and menus right, said it all. (Group high 5's were the payoff) Yet another happy camper headed down the road in Mobile audio bliss.
He could not use the sub at this point as he needed the cargo space for his other gear and such. But just trying the sub was well worth the time spent. When the time is right, he'll add a sub later.
OK, run your tests as noted and see what the results actually are. My bet is this amp is just too power hungry for the electrical system in this bucket for now. If that proves correct, you know the next steps.
Swez
SQLThump on 12/8/2007 15:46:04
Well, I have tried pretty much every thing I can think of, and the only thing left to try is hooking up the old amp. I have checked input voltage and it reads 13.7 with EVERYTHING on. With my old sub amp, the lowest it would drop was 12.9 when the bass was dropping as hard as possible. I looked up the instruction manual, and it will malfunction only if input voltage drops below 9 volts. So that removes that from the list.
My subs are good. I did not have a different sub available to test, so I dragged them into the house, and they both worked fine. My home theater would have shut off right away if there was a short in the subs. so scratch that.
I have tried every channel, whether bridged or not. Nothing will work here. tried disconnecting A and B channels, and leaving the other connected, still nothing. I have tried running it on HP, LP, with a variety of crossover settings, still nothing. It just won't work.
The only way I have been able to get any output whatsoever is by turning gain all the way down,sub output all tyhe way down. Fader all to the front, and H/U volume almost to the normal setting I use, and I can almost get some low end out of the amp.
I guess in my previous reant I could have better stated that I bought this amp from my freind who manages a shop, who i have known since middle school, and he cut me a killer deal on this amp. Since I am a freind, he has pulled ome strings, and a New amp is currently en-route from Texas, and will arrive in my town here sometime next week. It WILL be new in a box, and hopefully all will be well. I am going to hook up the old amp today to make sure everything else is kosher.
P.S. Swez, I checked every little thing imaginable in my system befroe posting, and I am completely stump on what tyhe hell is going on here. At this point, I am beginning to suspect some problem eith the H/U, as I have heard about them causing effects like this. My sister has a different deck I coukld check out, and I may try this. Anyway, iI'm gonna drag myself outside in the snow right now to check on this old amp. Lets hope all is well.....
swez on 12/8/2007 17:33:08
Interesting set of facts here SQL. Knowing all that, does point back to the amp itself.
Having low output and the protect circuits cycling in and out, points to internal amp guts problems. That might mean a few blown power transistors a few out of spec capacitors or a damaged power suppy system.
Anyway, all that and a $1.25 will get us a cup o COFFEE or a bag o chips. Here's to hoping the new amp works and gets the job done. Frankly, a Class D amp would be in order here, if your buddy can make a good one land in your lap?
Swez
PS Class D amps are fairly simple voltage multipliers and do that job very well. A well designed amp is reliable, robust and very efficient as well. (Less parts, but more robust ones, get the job done in this scenario)
SQLThump on 12/8/2007 21:34:24
The new (kind of good) news............
Hooked up the old amp, and it was the same problem, but on half the scale. Consiferdng it all worked fine, I went to the trunk to find one of my subs sounding completely devastated, and I find this funny as all seemed up to spec when I removed the subs from their boxes and inspected them. Guess it's time to pull some dustcaps and see how ugly these puppies look inside of them....
After hooking up the old amp, I put the new one back up to power, and remembered I had one good 8 inch sub in a dual bandpass box with a blown sub in the other chamber! VIOLA! A working speaker that doesnt involve disconnecting anything from the home theater.
Took those Puppies outside, and....It works!!!! Everything Works!!! Victory!!!!........except I don't have any working subs now, and a replacement is on the way from Texas. Doh!!! Now how to deal with both of these situations is sucking, especially since my trusty salesman is like my best freind, and I feel like a complete jackass right now...
So I decided to make a learning expeirence....How long would it take this amp to fry a low quality sub in a way mismatched box, with wattage approaching the rated 284 watts, firing in to this poor little 6 ohm devil.........
In literally a matter of seconds, with H/U volume at a healthy 20, and the gain around three quarters, this sub began to make a real nasty smell. a few more later, smoke was billowing out of the sound port, and it didn't stop until a few minutes after I ran iside and showed my brother and roomate. This guy was smoking like crazy! Cooked!
So the amp, with utmost confidence, definitely works. I still hhave a very small idea of how good it can sound, but hopefully new subs will be coming soon.
As for getting a Class D, I need this much power to be available to two seperate channels at 4 ohms. We were planning to run the upper bass drivers with the front channels, and the Dayton 15" sub on the rears, with the components on the amp I already have. Or if the amp I have proves works for the upper bass. It has it's own malfunction that made it not want to work with these subs, which I am wondering isn't the fault of those subs as well...
In either case, I am stoked to have the amp as per my original system plan, but totally bummed that I now have no bumps in the ride...........
swez on 12/9/2007 11:35:20
That is good news and yes, a "going bad" sub would indeed cause a good amp to sound bad or go into protect mode. (Mentioned that before did I not?)
It looks like some better subs are in order and soon huh? Now that the mid/highs are in place and doing OK, a pair of low budget Infinity Ref subs would be great on that new 4 channel. These are available in 4 ohm SVC's and 2+2 or 4+4 DVC coils. (300/350 Wrms respectively)
Some careful shopping would net a very low price too.
jamesp on 12/9/2007 16:24:45
Check out this link, Infinity Kappa's dual 2 or 4 Ohm for $73.85 ea. Refrence 12" same deal at $73.85 The VQ's are $134.85.
This is the best price on the Kappa's I have found. Not sure about the Refrence because I have not been pricing them..
Refrence shipping is $22.50 for 1 a pair may be a bit less ...
http://gallery.vendio.com/view/grandelectronics/ebay/index.html
SQLThump on 12/11/2007 01:16:20
I haven't built the components yet.......I decided the sub amp was the weakest link, and thought I could use the old subs with it......obviously those ghetto little guys weren't up to the task.
Swez, I did do a test of the subs, on my home theater, if a shorted speaker was ever hooked up before, it tripped a breaker, and it would shut off within seconds. All seemed normal, they sounded, looked and smelled OK, and I figured all was up to spec.
Lately my 5.1 reciever has been having some really strange, but hardly significant quirks. Just little stuff, like the sub out not making voltage if the unit is muted when it is turned off, an odd grounding problem a while back, and just today, static coming from the speakers. Odd stuff, but simply turning on and off the reciever corrects it. I can't complain. It was a gift horse anyway.
So what to do for subs now? I could go out and get some References, but this is contradictory to reason I bought this amp. My original plan was to power the comps I plan to build with the front channels of the GTO amp, a Dayton 15" for deep bass on the rear channel, and a pair of high effiecency 8's or 10's for upper bass, running on the JBL LC-A75.2 that I currently use for my front stage. I think I still want to stick to the original script here, and go with the Dayton 15"
A link to this sub...
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-560
The price is definitely right, and perfect for my goals and this amp. Hopefully I will have the extra dough to have 'er sent out next Monday.
As for the upper bass drivers, I may need to wait it out a bit longer, as I haven't decidet what drivers to use quite yet. We'll see about this in the future.
As for the front stage, I was going to get the parts to put them together after I replaced this amp, but I need bass now.......Rolling without it has definitely made me appreciete how good the little ghetto 20W Alpine 5.25's sound when there up to a loafing 75W JBL amp.
And at least I'm not totally screwed getting my bass fix, my home theater got's some mean 15" tower speakers that I use onlt for subs. Not the deepest bass, but everything above the 50hz rolloff is insane.
Just need to be patient, bide my time, and get everything put together. The Dayton is around the same price as the Reference, and I think it were yeild better results than the Infinity unit. We will see what I will score in a few weeks...
swez on 12/11/2007 02:51:40
OK, I remember that plan now and it was good then and still a good one now. The key is to stick to a good plan and avoid knee-jerk reactions as best as possible.
It appears this sub will do very well in a 1.5 cf sealed and has better than average eff too. The cabin gain will also help in the 50-70 Hz range and it also has a nice roll off curve for MB if you wished to use it as an extended range subwoofer/MB driver. (35 - 250 Hz.) Heck, this woofer could eliminate the need for separate MB speakers and amp with good EQ/LPF control. Only one way to find out... try a few things when you are able.
Swez
SQLThump on 12/11/2007 03:11:39
Actually, I was more of hoping to use it for more of an ultra deep bass driver, to cover around 60hz and below, and use the 10's or 8's for 60-200hz.
I know we talked about it earlier, but besides enclosure size, what would be some drawbacks to using an 18" version of the same woofer here? I understand it may be impractical, but the raw surface area makes me inclined to think it can put me on the path of having the absolute deepest bass possible in a midsize hoopty-bucket. I really don't care about trunk space, as long as I can wedge this muther in there.
I am having major problems deciding what to do for the upper range now. I am thinking of going crazy and putting some 10"s in the door, but I would need something with a slim profile, good performance, a pretty small enclosure requirement and most importantly, cheap.
Also wondering how much power loss I would be dealing with if an 8 ohm load was presented to the amp. I have seen a few 8 ohm drivers catching my eye, but am curious whether or not I will be able to extract enough power from the amp to make them hit.
Is there any other good websites besides Parts Express that offer good prices on some cheap drivers? I haven't found much yet.
swez on 12/12/2007 03:36:16
An 8 ohm driver will get 1/2 the wattage the amp can deliver at 4 ohms. That's about -3dB in terms of SPL differences.
PE is one of the best for the price. Madison Sound is another site for raw speakers, but they tend to be a lot more expensive too.
Going to an 18" sub cuts 2 ways...
1. Often need a very large box
2. Home gear is usually low power and Pro Audio is often 8 ohms and high power and cost
OK, I remember now that you did want a sub for the deep lows only and then use MB/MR/TW to fill in the rest. Most good quality 6.5 - 8" MB drivers will do 60 Hz and up just fine. The trick is mounting them into the doors so they look OK and don't bind.
Swez
SQLThump on 12/12/2007 16:48:50
Alright, glad to see we are on the same page again. I was thinking an 8 ohmer wouldn't recieve such a bad power cut since the amp doesn't double in power at 2 ohms, but rather a 40% increase. I figured going to 8 ohms wouldn't be such a steep penalty.
I will have to check out this Madison sound. I want to check out the fullest range of drivers possible before I make my choice.
The 18" sub I have in mind is pretty much the same Dayton Quattro as the 15" I've been looking at, but just an 18" model.
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=295-475&CFID=548036&CFTOKEN=68196667
Same power handling and ohmage, but an extra $10 dollars per inch of cone area. A price I would be willing to pay, as long as the Hoopty can have one of these stuffed in the back somehow......I can't keep this sub off my mind. I would probably be the only person in Northern Colorado knockin' an 18"
I still want to run midbass drivers, but I did a tally on the price of the components we designed, which was $192.20 without shipping, and think this may be going on hold for a while. The same buddy offered to sell me his old Infinity speakers from his wrecked Camry.
With 5.25 components for the front, and 6x8 coaxials for the rear, and a set of 14 inch studded snow tires, everything in this package is the same size I need, and he is offering me this at the low-low price of $160. I have heard the system in his old ride, and it really screamed, and the snows are virtually brand new. I really don't want the 6x8's as I don't want to use rear fill, but I'll probably bust them out as house speakers or something. Much more for less money, so I think I am going to go for it.......
Having trouble deciding what to do for midbass drivers though. I want everything below 150hz to sound like boomy sub bass, and cant decide what drivers to use. Is Goldwood a decent brand for cheap midbass drivers? there is quite a few models that would seem to offer the versitility I would require.
As for the door mount, I was thinking of building MDF enclosures for whatever driver I decide on, and then from there cut the door panels to fit them in there, attach them to the door somehow, and reupholster the door panel. As long as the enclosure doesn't stick too far out from the original door profile, this could work.....
swez on 12/13/2007 00:14:38
The Goldwood drivers are not bad if you amp them. Some have very low eff ratings and are available in 4 or 8 ohm units. They can take some good power too. (But need power to get the most from them)
The 18" vs the 15" Dayton, I don't see the benefit of this 18" sub for car use. A sealed or ported box for the 18" would be very large... make that huge, and not receommended.
Swez
SQLThump on 12/13/2007 04:24:44
Right on on the Goldwoods. I was thinking they may be alright, but wasn't sure, so I figured I would run it by good Old Man Audio first. They seem right for the price, and would make some decent low end until I get the ultimate sub bass. Now to decide what size.
The 8" model
http://www.partsexpress.com/pe/showdetl.cfm?Partnumber=290-357&vReviewShow=1&vReviewRand=820823#reviews
The 10" model
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-362
I was eyeing these because they were matching up nicely with the stereo wattage of the GTO, and could run them off the front channels to provide that deep midbass I want to compliment the Dayton 15".
But I am not too sure of the enclosure requirements of these drivers, which makes me second guess their ability foor door mount use. I think I may need to look around some more on these drivers.
I will take your word on the 18, but gotta ask one more question....
Would it make a good house sub to complement 50hz and below in the H/T? My 15's can make pound above that, but nothing super deep. how big of an enclosure would this puppy need for the crib?
swez on 12/13/2007 06:04:41
Used a pair of the Goldwods as replacement door speaks in my deceased Buick and they did well, but needed more power is all. Off the HU, they sounded good for range, but about -6dB lower than the stock rear speakers. (solid amp required) It was like this one, but no AV shielding:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-374
That 8" looks good down to 60 Hz, (F3) and still a solid 87dB at 2.83 volts. It peaks to 89.5 dB between 100 -150 Hz. and still solid above and belwo peak points. (Not a bad choice)
The 18" would make a nice HT sub. To get the correct box parameters, need a program to plug in the T/S parameters and plot it out like Ash does on his Pro Box design program. (Just looking at the Vas number told me this sub would like a very large box)
Swez
SQLThump on 12/14/2007 04:01:36
Where are you getting the response plots for the Goldwood? I haven't been able to get them.
Before I make a descision here, I need to find out how big of enclosures these 8's will need to make sure they are suitable for some sort of door mount......and hopefully one that doesn't involve some form of adhesive bonding strips.......
I will ask my sister if I can download WiniSD on her comp so I can crunch these numbers. I have been waiting for some time to put it on the POS comp I have been trying to peice together for some time now to work but to no avail.....
Maybe the Dyaton 18" will find a home then.......after my Bucket is finished.
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