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i have a system that consists of a 12 volt 18 amp hour battery, a planet audio BB1200.4 class D 4 channel amp, a JBL GT5-15 sub in free air, and a battery tender charger. at first, i was using proel flash 8p mini PA speakers as mains, but tonight, i hooked up a brand new pair of JBL Northridge N26AW II speakers with 16 gauge wiring (because that's all the shop up the street had) and within an hour of listening at low levels, the amp started making a low level squealing sound, sort of like a buzzy digitally distorted high frequency kissing noise, even after i turned my media player off.at the time, the sub was disconnected, but the wires were still in the amp, which shouldn't make a difference as the rear channel wasn't receiving a signal anyways as i also disconnected the rear ins i had split the left and right for with Y cables. when i'd used the proels, at first they were full range, but then i high passed them at 120Hz and low passed the sub at 120Hz too which was bridged on the rear channels when i had that. until the issues started with the JBLs tonight, everything was 12 gauge. when i hooked the JBLs up, i switched the front channels back to full range, and was using 4 feet per side of 16 gauge for the new speakers. i doubt it's related, but the sub had made plastic buzzing noises, that might have been the result of it reaching maximum excursion when i maxed the gain to be able to hear the sub in free air while the mains played at low volume.
after the first squealing incident, and checking that all of connections were both secure and that there were no shorts and the polarities were all correct, i started playing music again and within half an hour, the sound became intermittent, and the buzzing squeal returned.
after that, i tried to find out if it was possible for SPEAKERS to fry an amp... something i never heard of other than clipping an amp or running too low an impedance, but the JBLs are 8 ohms. that's when i read that supposedly frayed speaker wires can blow an amp. as the amount i stripped off the wires was too much for the amp's outputs, at first i curled the ends in on themselves so no exposed wire would be sticking out.
after reading that article, i went back and rewired the entire power system, except for the remote circuit, with 8 gauge wire with newly crimped O rings for the terminals as well as ditching the entire screw, nut & washers set that had corroded on the positive terminal with new ones as well as pulling the Y cables off and plugging my source directly into the front inputs. i also moved the power switch to only the remote circuit where before it controlled both that AND the positive terminal. as a side note, before that, the amp's led took a long time fading whenever i powered down, but now it blinks on an off instantly.
finally, regarding the corrosion, that was the circuit i was using with the original 12 gauge system i had no problems with until moving everything closer to where the JBLs are and hooking them up with the new 16 gauge wires.
when i listened to the proels, and also those with the sub, i used to connect my battery tender charger to offset the power drain while listening to music and disconnect it when i was done a few times, then started separate charging sessions when i was around to monitor the charger so as to mot overcharge the battery.
then, a few weeks ago, i noticed serious corrosion on both the terminal screw, nut and washers, along with nearly 1/2 an inch up the charger's alligator clips as well, and for a time, the charger stopped recognizing the battery when i reconnected it, until maybe after i brushed as much of the corrosion off as i could.
the last time i put the battery on the charger, it was indicating an 80% charge for nearly 24 hours worth of charging and never did reach full charge status.
so, does anyone have any ideas why a month or two old lightly used battery & charger would corrode or why my amp would freak out when i hooked a new pair of 8 ohm (easy load) speakers up without EVER turning volumes up loud? for what it's worth, it seems like the new right speaker isn't playing as loud as the left.
Edits: 01/14/17Follow Ups:
i also moved the power switch to only the remote circuit where before it controlled both that AND the positive terminal. as a side note, before that, the amp's led took a long time fading whenever i powered down, but now it blinks on an off instantly.
I'm not sure exactly what you changed, but now something is overloading your amp causing the power supply to drain and causing the LED to go out quickly. It could be speakers and wires or something internal.
There is also the possibility that your battery supply voltage is too low as reported by another poster.
Dark energy? Ridiculous!
We live in an electric universe.
before, BOTH the remote power and the positive power were on the switch, but now, the amp always sees power and only the remote is on the switch. i originally wired it the other way to prevent any potential parasitic drain on the battery.
now both the positive and negative power taps are on 8 gauge wiring and the remote is still on the original 12 gauge wiring with a 20 amp light switch as an interrupter.
Get your hands on a voltmeter and see what the battery is reading when noise occurs, with and without tender. And you can measure across corroded terminals to see if there is a voltage drop. And make sure you measure voltage at the amplifier 12V + to - while the music is playing. That is what you care about. One guess is that noise occurs when the voltage is low due to discharge or a weak battery or corrosion. Measuring before you clean the connections etc., will tell you if low voltage is the problem. An 18 amp battery isn't much power. I didn't look up your amplifier but some consume a lot of power
Search youtube clips etc., it will show you how to clean and seal battery terminals and why the corrosion occurs (different metals used for the contacts and battery gassing).
Like you wrote, some amplifiers don't like low impedance, so make sure your speaker wires aren't shorted + to -, and make sure that your crossover to the subs are hooked up as shown in crossover instructions.
If the voltage is OK and crossover etc., is hooked up correctly, you could have some kind of problem in the amplifier itself.
If it is an amplifier problem and you inquired about possible cause, you wrote: "at the time, the sub was disconnected, but the wires were still in the amp, which shouldn't make a difference as the rear channel wasn't receiving a signal anyways as i also disconnected the rear ins i had split the left and right for with Y cables. when i'd used the proels."
If you did this with 12 volts to the amplifier, signal or no signal, and the wires shorted, you could still damage the amplifier. Just depends on the amplifier, some designs are much better than others with dealing with shorts.
QUOTE: An 18 amp battery isn't much power. I didn't look up your amplifier but some consume a lot of powerthe amp shouldn't be consuming a lot of power as it's class D, so it should be at least 80% efficient on a bad day, and i'm not listening at high volumes at all. the battery itself should have at least an 80% charge as that's what the tender's indicator lights claimed the nearly 24 hours i had it on the charger before disconnecting it when i went to bed the next night and wouldn't be able to monitor it.
the amp has two 25 amp fuses i'm guessing that equal 25 amps for the front channels and 25 amps for the rears. it's ALLEGEDLY rated 4x300w at 4 ohms... allegedly. the fuses would say the amp has half the claimed power as 12v x 50ah = 600w. that's fine. i only bought it because it was the cheapest amp i could get that i could bi-amp & bridge. it sounds nice too. i've been a class D fan for years by now, and this amp actually sounds rather laid back and not at all cold & sterile, if not tube lush.
i know 18aH isn't a lot. that's not what i intended for the system once i get it rolling, it was only supposed to be used for testing the system, and in a "lite" system with just the proels which are 96db efficient. i planned on buying 3 more for 72aH, which someone in another forum thought was "too much", but i want long run times, an easy load on the batteries precisely because of the potential to over-drain them, and because i also intend to add a 100w inverter to power 5x8 watt LED lights.
i had just assumed it had to be the new speakers or wires causing the distortion as i haven't used the proels which played fine before i did the overnight charge, BUT i AM pushing the amp harder as the JBLs are only 88dB efficient and require nearly three times the power for the same level i still say isn't even 1 watt
i planned on getting a deluxe volt meter when the system's complete, but have considered it more important now after googling corrosion and learning that negative terminal corrosion indicates undercharging and positive terminal corrosion indicates overcharging. i've already tried to buy a meter locally, but the auto shop i visited didn't have those OR circuit breaker switches.
that the distortion is related to the corrosion just hadn't occurred to me, but it makes sense. i WANTED to buy a charger that works better than the tender, but got little help in a thread i started about that other than a recommendation for $200 "scientific chargers" and a member wanting to sell me a $100 he built, but couldn't be bothered to tell me WHY it was worth that much.
the AGMs are only supposed to be a short term fix until i can afford lighter lithium ion$ or poly$.
i just hooked the charger up, and it's indicating charging at less than 80% now when it should be closer to 99%, making me think the amp's draining the battery when it's off, as feared, with the main power always on.
thank you very much for your help. i'm afraid to even turn the system on now for fear of wasting the amp before i ever even get to really use it.
Edits: 01/14/17 01/14/17 01/14/17 01/14/17 01/14/17
It is the bass that consumes the power. Good chargers use SOC, inexpensive ones use voltage, that can easily be misleading.
Same recommendation, get your hands on a voltmeter. I was at a hamfest today, they were selling the ones they give away as a promotion at Harbour Freight for a dollar. If that's all you can do now, it is better than nothing, I think. That is if it has .1 volt resolution that is sufficient to tell you what is going on. Or ask around, maybe a friend has a voltmeter you can borrow.
The fading power light, I disregarded, assumed it was if you switch remote or power or both. You could experiment and find out.
i ALMOST went to sears to buy a power meter as that's about the only place i think i could get a digital meter seeing both the auto & battery stores i called didn't have them, but they start at $12 for ones i could get for half that on amazon, and i REALLY wanted to get one of these $16 meters instead.when i checked to see if harbor freight had volt meters online, the only results i found were for mutimeters that start at $5. i've seen coupons for those that are free with purchase, but in maybe 1 out of 10 ads.
as it stands, i've been charging the battery for about 10 hours or more by now, and it's STILL in charging mode (under 80% charge) when the charger was saying it was at at least 80% the entire time i last charged it before hooking the new speakers up.
i'll try to see if i can find a coupon for a free multimeter. i already have 2 flashlights too many and don't need the scissors in the latest ad i saw, but i planned to go there to get a drill, some bits, solder & an iron anyways to build the system. $5 isn't a lot for a multimeter that might be useful for other things like maybe measuring amp output once i learn how to use it.
if i DID get the multimeter, it would help me test if a really nice battery tender "jump starting" charger i saw at a thrift shop works, but my experience has been electronics at goodwill NEVER work and they refuse to do "thanks for your money SUCKER!" refunds.
Edits: 01/15/17 01/15/17 01/15/17
The power meter you included the picture of is a nice one. Would be a good addition to the DC audio system you are building, but a general purpose DVM would serve you better for this problem and other uses.
Goodwill's let you plug things in, try them. When you get a meter you could bring it along to test things like battery chargers.
well, the "fancy meter" will be better as this will be a bicycle trailer system, so i'll need a permanent display. that, plus it will look nice and hopefully tell me more than just my batteries' voltages. it's programmable too so i can set a low charge threshold warning to start flashing, even if it's behind me.i'm really wondering if the charger is working right as sometimes i have to jiggle it to get the indicator lights to turn on, and i'm still not convinced they're telling me the correct status to begin with.
it seems to change its mind about the percentage or status of charge in between doing nothing more than disconnecting it and reconnecting it the next day.
if memory serves me right, isn't 13.7v a full charge and 11.2v the lowest one should go?
i just hooked the charger up, and no lights came on. i shook the charger, and it indicated 75% then charging for a second and then the lights went out again. apparently, it only charges to 13.15v.
i'm using a harbor freight meter. my coupon for a freebie was expired, so i used a 20% off coupon. NOT a fan of the needle probes instead of alligator clips. they're a pain to deal with one handed, especially with curious cats knocking them loose from "wedged in". it's too bad i can just bolt them in to my distribution blocks for semi-permanent use until i get the programmable one, but a scan of the directions mentioned turning the unit on before completing circuits.
Edits: 01/18/17 01/18/17 01/18/17
the terminals are no longer corroded. i swapped the screw & nut for new ones and dropped the washers. the only thing corroded now is the charger's negative alligator clip."testing" things is hardly ever possible at goodwill unless you bring your own interconnects & cables and if the have an amp, there's no speakers and if the have speakers, no sources or amps etc. i just don't like buying from them after having to toss a heavy $15 door-stop, i mean receiver stuck in fault mode, because it was too heavy to carry a 2nd time, but everything lit up nice on it until i made the "mistake" of connecting speakers at home. i'd rather buy used gear at a place that properly tests it and guarantees it. i think the charger was just $12, and LOOKED to be in new condition with a box. i doubt it's still there though.
everything worked fine for over an hour last night after the charger indicated a 75%, i believe, charge, until my media player's battery went dead. i do think you were right about the amp undervolting. i gave the battery around a full day's charge after that, and haven't had any issues since. i might have been drawing a lot more power than i thought when the sub was still hooked up.
there's ANOTHER issue i have to resolve as the cone made a plastic buzzing noise on a couple tracks with really deep bass when i turned the mains up to something approaching a normal listening level with the sub bridged and its input maxed plus 50% bass boost too i think. i'm thinking it MIGHT be overexcursion related as it could be an impact related buzz, but my 1st guess was a loose dustcap.
i just powered the amp back up with a low volume load, and the voltage dropped to 12.87v quickly and got down to 12.82v within a few more minutes.
Edits: 01/18/17 01/18/17
in looking up how to measure watts, i got the multimeter version of V x A = W, so i decided to give it a go and right away got a very weird result. measuring the speaker out allen screws, i get -.09v (polarity correct) on the left channel and +.03v to +.04v on the right @20v meter setting. as i suspected, the left channel IS lower in volume, but the right channel is wired out of phase too.i got -.22a on the left and +.09a on the right at the 10 amp setting on the meter.
BTW, if i'm doing the math right, that = -3.98w on the left channel and +.72w on the left channel, right?
if the front mains left channel is wired out of phase, then maybe the rear channel's left is too so that would mean i MIGHT have been bridging the sub L positive to R positive. instead of L- to R+. now i wonder if MAYBE the buzzing was related to the sub bottoming out. THAT would cause a buzz i bet.
i reversed the inputs in case it had anything to do with the media player or the cables and got the same readings.
Edits: 01/18/17 01/18/17
The small DC voltages don't mean anything, just slight leakage at the output stage of the amplifier. If you see bass deflected (pushed in or out) with no sound, then you have a problem. Follow your wires to be sure amplifier + to speaker (or crossover) + and the phase will be correct. Don't know what kind of speaker wire you are using, but most have some indicator so you can determine one lead from the other at both ends. On lamp cord, one has small ridges.
Over 13+ volts is battery float voltage. After a few minutes of playing it will drop to 12 something, that is normal. To see if the problem you are having is battery drain, play it until you hear the problem and check the DC voltage at the amplifier.
If you continue to have problems and want to talk about it, I accept e-mails, send me phone number and I will call you.
Prolly not helpfull :-)
In My dabblings with D amps I will only say these are too often Junk.
Buy Cheap = Buy twice or if Obtuse; repeatedly
You could try a Car Battery yup yank your cars' battery and see what happens when it's thge power source.
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