So I just decided to put new back speakers in my Escape. I already have the fronts hook up to my 4-way amp. I wired everything up and all works fine except it seems that one of my negative leads on the amp is dead. If I hook up one speaker to the other +/- it works fine but then if I hook up to that set it does not. Positive is fine because I can bridge to a different negative and it works.
Is this a suffiecient test to determine that the lead is bad?
Is this an easy fix? i.e. taking the amp apart.
Any ideas would be greatly appreciated!
Thanks,
John
Replies (4)
swez on 03/27/2006 20:23:24
An Ohm meter would be the proper test tool, or a "Continuity" tester will also work.
All speaker ground terminals on the amp should be common to each other. If one channel has lost its ground, it's possible the PC board has a bad solder joint and therefore, not a proper ground for your speaker on that channel.
Test Steps:
1. Pull the main power fuse that feeds this amp (it must be unpowered)
2. With all speaker wires disconnected from amp, measure ohmic readings with one probe on a known good channel, and probe each channel speaker ground lugs
Meter Method Test:
All grounds should read 'Zero' ohms from one terminal to all other grounds. If you find one that read infinity or very high ohmic value, that's your problem lug. The amp needs to be opened, pull the PC board and re-solder the bad lug.
Continuity Test Method:
This is a test lamp with a battery, lamp and +/- test probes. Any autoparts store will carry them cheap. Here, the lamp lights when the Pos and Neg probes are shorted together. (A closed circuit)
Same test procedure as noted with meter, one probe on known good ground. Probe the remaining 3 ground with the other probe. (Polarity is not an issue) If the lamp lights as you probe each ground lug, all grounds are good. If you find a "flier', (a lug that lamp does not light up with) that's the loose ground connection.
Again, the PC board has to be looked at and re-soldered.
Swez
turbopsu on 03/28/2006 13:26:44
Thank you very much Swez... The solder joint was bad on that terminal so I fixed that easily. Now, however, it doesn't seem to be able to pump as much as I thought it would. I have the gain turned down completely and 4 door speakers hooked up. The amp will cut out if I turn the volume up too much. I didn't have this problem when I had just the fronts hooked up and a 12" sub bridged across the other 2 outs.
Could the problem be that I have just the front feed from the HU going to the OEM converter and then that signal being sent to the front and back inputs of the amp? If this isn't the issue any ideas would be greatly appreciated.
Thanks again!!
Terry
ttocs on 03/28/2006 15:04:19
if the amp gain is all the way down you will not get much out of it.......
swez on 03/28/2006 17:18:11
The signal level from the HU, determines the amp gain settings.
Example:
1. Say your HU is rated at 2.5 volts from the RCA preamps
2. Amp has gain settings between 0.25 - 4.0 volts (most - least sensitivity setting marks)
Solution: We set the amp gains at 2.5 volts (+/- 0.5 volts)
Now, suppose we have only 1 pair of RCA's in a HU and the amp has 4 inputs. Some amps have switches or a control panel that can operate all 4 channels, with as few as 1 pair of RCA's. If your amp has that feature, use that.
If your amp does not have such a feature, we use "Y" patch cords that split 1 pair, into 2 pairs of RCA males. (I assume this is what you have now?) This will work, but we need to adjust the amp gains in a different manner, by measuring voltage output from each channel. Need an AC voltmeter for this test. Can give more details later, as needed.
What amp make and model # are you using here? And, what is the fuse value(s) used by this amp? (Ie: 1 x 30A; 2 x 20A; 2 x 30A ?)
Based on your answers, can help you tweak the gains for max clean output and not overload the amp.
Swez COFFEE
PS Read this posting as it covers all the details for dialing in amp gains for maximum performance. If the amp shuts down at high SPL levels, the gain settings on the amp are incorrect.
http://www.clubknowledge.com/Car_Audio_FAQ/?g4093_2580
Is this a suffiecient test to determine that the lead is bad?
Is this an easy fix? i.e. taking the amp apart.
Any ideas would be greatly appreciated!
Thanks,
John
Replies (4)
swez on 03/27/2006 20:23:24
An Ohm meter would be the proper test tool, or a "Continuity" tester will also work.
All speaker ground terminals on the amp should be common to each other. If one channel has lost its ground, it's possible the PC board has a bad solder joint and therefore, not a proper ground for your speaker on that channel.
Test Steps:
1. Pull the main power fuse that feeds this amp (it must be unpowered)
2. With all speaker wires disconnected from amp, measure ohmic readings with one probe on a known good channel, and probe each channel speaker ground lugs
Meter Method Test:
All grounds should read 'Zero' ohms from one terminal to all other grounds. If you find one that read infinity or very high ohmic value, that's your problem lug. The amp needs to be opened, pull the PC board and re-solder the bad lug.
Continuity Test Method:
This is a test lamp with a battery, lamp and +/- test probes. Any autoparts store will carry them cheap. Here, the lamp lights when the Pos and Neg probes are shorted together. (A closed circuit)
Same test procedure as noted with meter, one probe on known good ground. Probe the remaining 3 ground with the other probe. (Polarity is not an issue) If the lamp lights as you probe each ground lug, all grounds are good. If you find a "flier', (a lug that lamp does not light up with) that's the loose ground connection.
Again, the PC board has to be looked at and re-soldered.
Swez
turbopsu on 03/28/2006 13:26:44
Thank you very much Swez... The solder joint was bad on that terminal so I fixed that easily. Now, however, it doesn't seem to be able to pump as much as I thought it would. I have the gain turned down completely and 4 door speakers hooked up. The amp will cut out if I turn the volume up too much. I didn't have this problem when I had just the fronts hooked up and a 12" sub bridged across the other 2 outs.
Could the problem be that I have just the front feed from the HU going to the OEM converter and then that signal being sent to the front and back inputs of the amp? If this isn't the issue any ideas would be greatly appreciated.
Thanks again!!
Terry
ttocs on 03/28/2006 15:04:19
if the amp gain is all the way down you will not get much out of it.......
swez on 03/28/2006 17:18:11
The signal level from the HU, determines the amp gain settings.
Example:
1. Say your HU is rated at 2.5 volts from the RCA preamps
2. Amp has gain settings between 0.25 - 4.0 volts (most - least sensitivity setting marks)
Solution: We set the amp gains at 2.5 volts (+/- 0.5 volts)
Now, suppose we have only 1 pair of RCA's in a HU and the amp has 4 inputs. Some amps have switches or a control panel that can operate all 4 channels, with as few as 1 pair of RCA's. If your amp has that feature, use that.
If your amp does not have such a feature, we use "Y" patch cords that split 1 pair, into 2 pairs of RCA males. (I assume this is what you have now?) This will work, but we need to adjust the amp gains in a different manner, by measuring voltage output from each channel. Need an AC voltmeter for this test. Can give more details later, as needed.
What amp make and model # are you using here? And, what is the fuse value(s) used by this amp? (Ie: 1 x 30A; 2 x 20A; 2 x 30A ?)
Based on your answers, can help you tweak the gains for max clean output and not overload the amp.
Swez COFFEE
PS Read this posting as it covers all the details for dialing in amp gains for maximum performance. If the amp shuts down at high SPL levels, the gain settings on the amp are incorrect.
http://www.clubknowledge.com/Car_Audio_FAQ/?g4093_2580
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