HELP: Amp Won't Turn On?
10-19-2010, 01:22 AM
#11
0 Watt CAFz'r
Thread Starter
Join Date: Dec 2007
Posts: 11
Also, thanks for the tip on jumping the remote wire with the 12V source. I'll be sure to try that.
As well, I also read that it's not a bad idea to try another fuse even though the current one looks to be fine. I should have an extra kickin' around.
As well, I also read that it's not a bad idea to try another fuse even though the current one looks to be fine. I should have an extra kickin' around.
10-20-2010, 02:20 PM
#13
^^protects the remote on circuit in the head unit in case the amp blows..some amps have very high current draw though the remote circuit when they blow and it can fry the remote circuit. If you have more than 1 amp or amps and processors etc.. Use a relay to turn everything on.
10-20-2010, 03:28 PM
#15
^^protects the remote on circuit in the head unit in case the amp blows..some amps have very high current draw though the remote circuit when they blow and it can fry the remote circuit. If you have more than 1 amp or amps and processors etc.. Use a relay to turn everything on.
THe chances that your amp has a catastrophic failure that would cause 50 or 100 volt power supply rails to short to the remote input, is, pardon my pun, remote..
10-20-2010, 03:30 PM
#16
It's the old 1% of the time it can happen routine. For the time and effort needed, it's not a bad precaution, especially on more expensive decks. I've never had it happen to me either, but after reading the scenario on BCAE, I thought it a good idea for a $600.00 deck. Here is a few excerpts from BCAE under amplifiers (#23 on right hand side):
Remote Input Current:
The remote input current for amplifiers varies with the amplifier and the model. Some draw minimal current. Others draw a little more. The upper limit of a properly functioning amplifier is approximately 50ma (0.05 amps). If you're using/controlling more than 2 amplifiers, it is (in my opinion) much better to use a relay to control the amplifiers. Actually I really prefer having a relay in the remote circuit (no matter how many amplifiers I'm using) because it protects the head unit's remote output circuit in case of a short circuit. The following chart shows the remote input current for various amplifiers I had laying around the shop.
Note:
There is at least one very popular brand of amplifier that draws as much as 500ma of current when the amplifier fails. This is enough to damage the remote output switching transistor in the head unit if the fuse is missing or is of the wrong value. A relay in the remote circuit will completely eliminate the possibility of damaging the head unit in this situation.
and this was from the head unit section (# 22):
Again with the fuse thing...
Most remote outputs are switched through a very small transistor. This means that they are EASILY damaged by excessive current flow. They should be fused close to the head unit with a .5 amp fuse. A 1 amp fuse may not protect the switching transistor, which supplies power to the remote output. Do not try to use the remote output to power fans directly.
Remote Input Current:
The remote input current for amplifiers varies with the amplifier and the model. Some draw minimal current. Others draw a little more. The upper limit of a properly functioning amplifier is approximately 50ma (0.05 amps). If you're using/controlling more than 2 amplifiers, it is (in my opinion) much better to use a relay to control the amplifiers. Actually I really prefer having a relay in the remote circuit (no matter how many amplifiers I'm using) because it protects the head unit's remote output circuit in case of a short circuit. The following chart shows the remote input current for various amplifiers I had laying around the shop.
Note:
There is at least one very popular brand of amplifier that draws as much as 500ma of current when the amplifier fails. This is enough to damage the remote output switching transistor in the head unit if the fuse is missing or is of the wrong value. A relay in the remote circuit will completely eliminate the possibility of damaging the head unit in this situation.
and this was from the head unit section (# 22):
Again with the fuse thing...
Most remote outputs are switched through a very small transistor. This means that they are EASILY damaged by excessive current flow. They should be fused close to the head unit with a .5 amp fuse. A 1 amp fuse may not protect the switching transistor, which supplies power to the remote output. Do not try to use the remote output to power fans directly.
Last edited by veeman; 10-20-2010 at 04:01 PM.
10-20-2010, 03:37 PM
#17
You are basically assessing risk of failure. Your information on risk may not be accurate. But just like insurance, it makes you feel better! go for it!
10-20-2010, 04:14 PM
#18
^^certainly, that's what good installation is all about (at least from a safety, prevention of problems point of view). Anywhere there is a reasonable risk of shorting or over current is a good place to fuse. A remote wire carrying 12 volts though your car to the rear amplifier is a good candidate for fusing regardless of possible over current damage from an amp failing. Anywhere along the line it could short if it comes into contact with a metal part of the car.
10-20-2010, 05:49 PM
#19
500 Watt CAFz'r
Join Date: Oct 2009
Posts: 730
^^certainly, that's what good installation is all about (at least from a safety, prevention of problems point of view). Anywhere there is a reasonable risk of shorting or over current is a good place to fuse. A remote wire carrying 12 volts though your car to the rear amplifier is a good candidate for fusing regardless of possible over current damage from an amp failing. Anywhere along the line it could short if it comes into contact with a metal part of the car.
Sorry, but did you even read the fuse portion of BCAE??? Number 14?? LOL
The fuse protects the wire, not the deck.... At catastrophic failure, a fuse can through-put much more voltage/amperage than needed to fry that deck. The fuse is there to prevent the wire from burning up and causing a fire, not protect the components. Plus, even if you ground out the remote wire, the deck will shut down to open the circuit, just like Yuli said.
10-20-2010, 06:41 PM
#20
[QUOTE=veeman;619304]Note:
There is at least one very popular brand of amplifier that draws as much as 500ma of current when the amplifier fails. This is enough to damage the remote output switching transistor in the head unit if the fuse is missing or is of the wrong value.QUOTE]
electronics do not "draw" current unless they are constant current source. They provide a load into which a source will sink current into. And if something fails I cannot see how it somehow fails into a current source that will draw 500mA.
The output circuits of a remote control is a transistor and a resistor in series. If it is shorted out it maximum current will flow depending on the resistor, No more, Unless like I said somehow the failing amp puts rails on the remote input. Anyway we will all do as we please
There is at least one very popular brand of amplifier that draws as much as 500ma of current when the amplifier fails. This is enough to damage the remote output switching transistor in the head unit if the fuse is missing or is of the wrong value.QUOTE]
electronics do not "draw" current unless they are constant current source. They provide a load into which a source will sink current into. And if something fails I cannot see how it somehow fails into a current source that will draw 500mA.
The output circuits of a remote control is a transistor and a resistor in series. If it is shorted out it maximum current will flow depending on the resistor, No more, Unless like I said somehow the failing amp puts rails on the remote input. Anyway we will all do as we please
