I installed a new stereo last year and scabbed the power to operate from a nearby light. I had just bought this boat and was over my head in projects and this was the easiest and quickest way to bring power. The PO did the same thing with an old car stereo, so I just followed his lead. My problem is that when I reach 25 on the volume which is loud, but is probably only about one-half of what this JBL Sirius Stereo is capable of, the stereo will quit and restart. I assume the wires coming from the lights are way too small in gauge or too light! I plan on running heavier gauge wire direct from a separate circuit breaker in the electric panel. Has anyone else ever experienced a similar situation and if so, how did you solve and what gauge wire did you use? Now I know what you are all thinking - Why does a guy who is 52 need to listen to a stereo more than half volume? Well because I grew up in the 70's and I am still young at heart. Greg W "SlipAway"
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There is a wire gauge table that will give
the desired gauge once you determine the maximum current that will be travelling through the wire and the length of travel. Check the radio specs for its maximum power draw and then figure out the distance from the radio unit to the breaker and the distance to ground. I have no problem if you want to blow out your ear drums while you are out sailing but if your idea of being young at heart is to impose your taste of music on others at a marina or anchorage you'll get no sympathy from me.
the desired gauge once you determine the maximum current that will be travelling through the wire and the length of travel. Check the radio specs for its maximum power draw and then figure out the distance from the radio unit to the breaker and the distance to ground. I have no problem if you want to blow out your ear drums while you are out sailing but if your idea of being young at heart is to impose your taste of music on others at a marina or anchorage you'll get no sympathy from me.
I kinda ran into the same problem...
I have my sound system tied into the same circuit as the VHF radio, figuring both wouldan't be operating at the same time. I have a Seaworthy unit, its made by Prospec, as is your JBL unit. The boat had been in the water for about 2 weeks while I did some work on it. One of the last things I did was connect the cockpit speakers. Prior to that the system was playing fine through the cabin speakers. After playing for a short time, the sound cut out. I reset the unit and tried it again... same thing. Sound would play for a minute or two but eventually cut out. The front of the player acted normally... it would light up, tune stations, etc, just no sound. I resolved to troubleshoot it sometime in the future. I figured I would need to replace it. Before I left that day I noticed my onboard battery charger was not switched on. The boat had been in the water for 2 weeks with me working on things, flushing the bilge, flushing the freshwater system, playing a radio, turning on lights, etc. I did not however, start the engine. Apparently, the battery was not being charged all this time. So, I made sure I switched it on. It never occurred to me that low battery voltage could be the reason for the radio malfunction. When I went back last weekend with plans to troubleshoot the sound system, lo and behold it was working fine. I tried everything short of popping speaker cones trying to get it to cut out. It never did. I can only conclude that the amplifier section of these units stops functioniong under low voltage conditions. That's my story and I'm sticking to it. Ain't Sirius the cats pajamas on the boat?
I have my sound system tied into the same circuit as the VHF radio, figuring both wouldan't be operating at the same time. I have a Seaworthy unit, its made by Prospec, as is your JBL unit. The boat had been in the water for about 2 weeks while I did some work on it. One of the last things I did was connect the cockpit speakers. Prior to that the system was playing fine through the cabin speakers. After playing for a short time, the sound cut out. I reset the unit and tried it again... same thing. Sound would play for a minute or two but eventually cut out. The front of the player acted normally... it would light up, tune stations, etc, just no sound. I resolved to troubleshoot it sometime in the future. I figured I would need to replace it. Before I left that day I noticed my onboard battery charger was not switched on. The boat had been in the water for 2 weeks with me working on things, flushing the bilge, flushing the freshwater system, playing a radio, turning on lights, etc. I did not however, start the engine. Apparently, the battery was not being charged all this time. So, I made sure I switched it on. It never occurred to me that low battery voltage could be the reason for the radio malfunction. When I went back last weekend with plans to troubleshoot the sound system, lo and behold it was working fine. I tried everything short of popping speaker cones trying to get it to cut out. It never did. I can only conclude that the amplifier section of these units stops functioniong under low voltage conditions. That's my story and I'm sticking to it. Ain't Sirius the cats pajamas on the boat?
Many stereos are rated at peak power
The truth about 12V stereos is that the voltage at the batteries is converted directly into AC voltage for the sound. That means if you have voltage drop in your DC wires, you have less voltage to produce sound. So, size your wires for peak power. If your peak power is 50W, divide that by 12V and you get 50/12 = 4.2Amps. Wire charts will tell you that you could get away with 16 Gauge(or less). Personally, I would not wire it with anything less than 14 Gauge. You should look at your voltage drop when sizing wire - if your runs are long, you want to bump up a wire size. I always try to have around a 2% drop. Less voltage drop means louder peaks. So, always wire conservatively when sizing wire. This is also true of the speaker wires!
The truth about 12V stereos is that the voltage at the batteries is converted directly into AC voltage for the sound. That means if you have voltage drop in your DC wires, you have less voltage to produce sound. So, size your wires for peak power. If your peak power is 50W, divide that by 12V and you get 50/12 = 4.2Amps. Wire charts will tell you that you could get away with 16 Gauge(or less). Personally, I would not wire it with anything less than 14 Gauge. You should look at your voltage drop when sizing wire - if your runs are long, you want to bump up a wire size. I always try to have around a 2% drop. Less voltage drop means louder peaks. So, always wire conservatively when sizing wire. This is also true of the speaker wires!
Only good vibrations Landsend..
There are output transistors in what they call a full bridge configuration that is connected directly to the battery. So if you provide 12V DC, the maximum AC voltage that can be produced is 12V Peak - of course you have to subtract the transistor voltage drop. Thats why they clip and distort at high power. Many signals start to look like a square wave under high power because they lack high enough voltage to get to their peak. They peak out early and become flat topped.
There are output transistors in what they call a full bridge configuration that is connected directly to the battery. So if you provide 12V DC, the maximum AC voltage that can be produced is 12V Peak - of course you have to subtract the transistor voltage drop. Thats why they clip and distort at high power. Many signals start to look like a square wave under high power because they lack high enough voltage to get to their peak. They peak out early and become flat topped.
So Guy,
Are you saying a bridge rectifier puts out AC current? I thought it was the other way around.
Are you saying a bridge rectifier puts out AC current? I thought it was the other way around.
Just that sound is "AC"
I think the point Guy is making is that sound through the speakers is, so to speak, an "AC" current i.e. a sinusoidal wave. Maximum voltage would be whatever the maximum DC voltage is. Paul
I think the point Guy is making is that sound through the speakers is, so to speak, an "AC" current i.e. a sinusoidal wave. Maximum voltage would be whatever the maximum DC voltage is. Paul
Who said anything about rectifiers, Fred??
There is a "Full Bridge/Wave Rectifier" that consists of diodes alone. In that case, you would be correct. But I did not say anything about a rectifier. I said "Full Bridge" which in power conversion consists of solid state transistors (such as MOSFET's) that convert DC into AC. The full bridge is used everywhere from motor drives, inverters, welders, stereos, etc....
There is a "Full Bridge/Wave Rectifier" that consists of diodes alone. In that case, you would be correct. But I did not say anything about a rectifier. I said "Full Bridge" which in power conversion consists of solid state transistors (such as MOSFET's) that convert DC into AC. The full bridge is used everywhere from motor drives, inverters, welders, stereos, etc....
Link for Lansend
Landsend, here is a link that describes what I was trying to explain about clipping. If the DC voltage is only 12V and the amplifier tries to produce an AC voltage greater than its source(12V) the signal clips and becomes distorted.
Landsend, here is a link that describes what I was trying to explain about clipping. If the DC voltage is only 12V and the amplifier tries to produce an AC voltage greater than its source(12V) the signal clips and becomes distorted.
Diagnose the problem
So when you added the additional cockpit speakers the system shuts down after a few minutes and you can repeat the problem. sounds like you have added an additional load in parallel (cockpit speakers) and that has lowered the overall resistance the output amp is seeing and sending it into an over current shutdown. did you wire the cockpit speakers in parallel with the cabin speakers or does the stereo have an additional (A and B) pair of outputs? Basicly two 8 ohm speakers wired in parallel give you 4 ohms resistance which is too low and causes an over current shutdown and you can't wire them in series as that would give 16 ohms which is too high to get any output or at least not much.
So when you added the additional cockpit speakers the system shuts down after a few minutes and you can repeat the problem. sounds like you have added an additional load in parallel (cockpit speakers) and that has lowered the overall resistance the output amp is seeing and sending it into an over current shutdown. did you wire the cockpit speakers in parallel with the cabin speakers or does the stereo have an additional (A and B) pair of outputs? Basicly two 8 ohm speakers wired in parallel give you 4 ohms resistance which is too low and causes an over current shutdown and you can't wire them in series as that would give 16 ohms which is too high to get any output or at least not much.
Bill, Greg has the problem, not me...
I tracked the problem with mine down to inadequate battery voltage. I was suggesting to Greg that he should check this as well since low battery voltage can apparently cause the amplifier section of the unit to malfunction, even though it appears that the unit is functioning normally. The cockpit speakers have always been in my system. They are wired off the fader as the rear set, just like in a car. They are 4 ohm. That is what most auto speakers are and what most head units expect the speaker impedance to be. I did check when I first noticed the problem that I didnt have a direct short at the connection terminals. I didnt.
I tracked the problem with mine down to inadequate battery voltage. I was suggesting to Greg that he should check this as well since low battery voltage can apparently cause the amplifier section of the unit to malfunction, even though it appears that the unit is functioning normally. The cockpit speakers have always been in my system. They are wired off the fader as the rear set, just like in a car. They are 4 ohm. That is what most auto speakers are and what most head units expect the speaker impedance to be. I did check when I first noticed the problem that I didnt have a direct short at the connection terminals. I didnt.
GuyT, you are wrong in your statement about voltages unable to exceed 12v
You are correct with how you explain clipping, but saying that a mobile amplifyer cannot produce a waveform greater than 12v is not correct. It is correct to say the amp cannot produce a waveform with a voltage greater than its rail voltage, but the rail voltage is not limited to 12v. Consider a power supply where we take the 12vdc and convert it to AC. Then pass the AC through a transformer. Transformers wired with more turns on the seconday will increase the voltage the same way transformers with less turns on the secondary will decrease it. So depending on the transsformer used, the AC voltage will increase. Once we have the increased voltage AC, we can always rectify it back to DC at a higher voltage if needed. What changes through all this is the current draw from the battery. This is exactly how mobile amplifiers work. See the link below. it might explain it better.
You are correct with how you explain clipping, but saying that a mobile amplifyer cannot produce a waveform greater than 12v is not correct. It is correct to say the amp cannot produce a waveform with a voltage greater than its rail voltage, but the rail voltage is not limited to 12v. Consider a power supply where we take the 12vdc and convert it to AC. Then pass the AC through a transformer. Transformers wired with more turns on the seconday will increase the voltage the same way transformers with less turns on the secondary will decrease it. So depending on the transsformer used, the AC voltage will increase. Once we have the increased voltage AC, we can always rectify it back to DC at a higher voltage if needed. What changes through all this is the current draw from the battery. This is exactly how mobile amplifiers work. See the link below. it might explain it better.
Hold your horses, Primerese!!
Read my posts. Number 5 specifically. I said voltages can not get above 12V with a simple bridge connected directly to the batteries! Of course you can step up the voltages to drive a bridge with a higher voltage to get more power. DUH !! I dont need a link to tell me that. Before you call someone wrong, you should read a little more.
Read my posts. Number 5 specifically. I said voltages can not get above 12V with a simple bridge connected directly to the batteries! Of course you can step up the voltages to drive a bridge with a higher voltage to get more power. DUH !! I dont need a link to tell me that. Before you call someone wrong, you should read a little more.
It still comes down to small gauge wire
As we all know, a smaller guage wire has more voltage drop across its run. The higher the current draw, the greater the actual drop. Good old Ohm's law is in charge. So probably as he turns up the volume, the audio PA draws more current, the voltage presented to the radio (paticularly on audio peaks with short but larger current draw) drops below the point where the regulators run out of head room. Vcc drops (even momentary) to the point where the CPU glitches or its reset pin drops enough to cause a reset. As GuyT says, run some #14 or even better #12. And don't forget to make sure of the ground side. It closes the other end of the circuit.
As we all know, a smaller guage wire has more voltage drop across its run. The higher the current draw, the greater the actual drop. Good old Ohm's law is in charge. So probably as he turns up the volume, the audio PA draws more current, the voltage presented to the radio (paticularly on audio peaks with short but larger current draw) drops below the point where the regulators run out of head room. Vcc drops (even momentary) to the point where the CPU glitches or its reset pin drops enough to cause a reset. As GuyT says, run some #14 or even better #12. And don't forget to make sure of the ground side. It closes the other end of the circuit.
The Stereo Wars
Well, I didn't mean to start a war about stereos! I am appreciative of all of the help and will rewire with 12 gauge. I probably won't ever listen to it much louder than 30 or so, but I am a perfectionist and when it cuts out, it bugs the hell out of me! Greg W "SlipAway"
Well, I didn't mean to start a war about stereos! I am appreciative of all of the help and will rewire with 12 gauge. I probably won't ever listen to it much louder than 30 or so, but I am a perfectionist and when it cuts out, it bugs the hell out of me! Greg W "SlipAway"
Believe what you want
Landsend, I never said the problem was from clipping - it was just a side comment about AC and amplifiers. And your comment about Audio not being AC - lets just say that a friend of mine, Mr. Hertz and his cousin Kilo Hertz do not agree with you. I believe that their job is to accurately describe AC frequency. As sure as I am alive on this planet - Audio waveforms from the output of an amplifier to a speaker are AC.
Landsend, I never said the problem was from clipping - it was just a side comment about AC and amplifiers. And your comment about Audio not being AC - lets just say that a friend of mine, Mr. Hertz and his cousin Kilo Hertz do not agree with you. I believe that their job is to accurately describe AC frequency. As sure as I am alive on this planet - Audio waveforms from the output of an amplifier to a speaker are AC.
Fred, the internal components of a system are powered by DC
but the signal that is sent to the speakers are a continuously varying signal. That signal is applied to the speaker coil which converts the electronic signal to a mechanical action - it causes the speaker cone to vibrate based on the incoming continuously varying signal - AC. Your 8 Track is simply using the car chassis as a common.
but the signal that is sent to the speakers are a continuously varying signal. That signal is applied to the speaker coil which converts the electronic signal to a mechanical action - it causes the speaker cone to vibrate based on the incoming continuously varying signal - AC. Your 8 Track is simply using the car chassis as a common.
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