Speaker movement after amp turned off question.

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BigSkyCory

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I am currently using an Adcom gfa 5400 with Phase Linear 2000 pre amp. After I turn my amp off the speakers move a little bit, looks like they suck in then push back out. I was told this is my amp. My main concern is, is this doing any harm to my speakers? Speakers are - Energy Connoisseur Series C-5.

Cory.
 
laatsch55

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Cory, i believe that is answered on the power vs freq thread. It appears to be as a direct result of DC offset at the speaker out terminals. Do you have a voltmeter?
 
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It is your main power supply filters in your amp decaying assymetrically when you turn the amp off. It is subsonic.
 
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frhodes said:
Do you know how long it takes for the power caps to fully charge?
Click to expand...

Discharge or charge.

On turnon, the bulk caps will charge fully in a couple of cycles, about 50msec unless the amp has some special soft start features in it.

On discharge, depending on the size of the bulk caps, it could take 30 seconds or longer. In the PL amps with increased bulk caps, this takes over 15 seconds.
 
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Gepetto said:
Discharge or charge.

On turnon, the bulk caps will charge fully in a couple of cycles, about 50msec unless the amp has some special soft start features in it.

On discharge, depending on the size of the bulk caps, it could take 30 seconds or longer. In the PL amps with increased bulk caps, this takes over 15 seconds.
Click to expand...
The reason I asked is I'm replacing the power caps in a MCS 3125 that had 6800uf 80v's with 10,000uf 80v's. With shipping the 10,000's are the best buy. The receiver has a protection relay so the increase shouldn't be any problem?
 
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frhodes said:
The reason I asked is I'm replacing the power caps in a MCS 3125 that had 6800uf 80v's with 10,000uf 80v's. With shipping the 10,000's are the best buy. The receiver has a protection relay so the increase shouldn't be any problem?
Click to expand...
Be very carefull where you are getting your caps.
 
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Anything off of Ebay...especially from Asia.


  • Be sure that your capacitors are from well-known manufacturers (Nichicon, Panasonic, United Chemi-con, Nippon Chemi-con, Cornell Dubilier (CDE), Rubycon, etc.) and are coming from one of their authorized distributors.
  • There are many counterfeit capacitors available that appear to be the right working voltage and appear to be from respected manufacturers available on the web. Beware! These are usually lower voltage capacitors that have been shrink wrapped with lookalike wrapping to make them appear that they are from the legitimate manufacturer. These usually are missing the production date code and lot code information that these manufacturers always add. Buyer beware, if the ratings or cost look too good to be true, they usually are counterfeit. Do not use counterfeits.
  • Capacitors that have been stored improperly or are very old may no longer be functional and may fail catastrophically.
  • It is possible to use new old stock (NOS) capacitors in this kit but make sure that they are properly formed before use and that the capacitor leakage current is proper at the rated voltage of the capacitor. It is highly recommended that you form and test NOS capacitors before deploying them in your application.
  • Recommended Mouser Electronics selections that have been tested and work well with this kit:
    • 667-ECO-S2AP682EA = 6,800uF 100V 35mm Diameter by 50.8mm Long, 2 pin snap in, 10mm lead spacing, Panasonic
    • 667-ECE-T2AP822EA= 8,200uF 100V 35mm Diameter by 63mm Long, 4 pin snap in, 22.4mm lead spacing, Panasonic
    • 661-ESMH101VND103MA6= 10,000uF 100V 35mm Diameter by 63mm Long, 4 pin snap in, 22.4mm lead spacing, United Chemi-con
 
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Gepetto said:
Anything off of Ebay...especially from Asia.


  • Be sure that your capacitors are from well-known manufacturers (Nichicon, Panasonic, United Chemi-con, Nippon Chemi-con, Cornell Dubilier (CDE), Rubycon, etc.) and are coming from one of their authorized distributors.
  • There are many counterfeit capacitors available that appear to be the right working voltage and appear to be from respected manufacturers available on the web. Beware! These are usually lower voltage capacitors that have been shrink wrapped with lookalike wrapping to make them appear that they are from the legitimate manufacturer. These usually are missing the production date code and lot code information that these manufacturers always add. Buyer beware, if the ratings or cost look too good to be true, they usually are counterfeit. Do not use counterfeits.
  • Capacitors that have been stored improperly or are very old may no longer be functional and may fail catastrophically.
  • It is possible to use new old stock (NOS) capacitors in this kit but make sure that they are properly formed before use and that the capacitor leakage current is proper at the rated voltage of the capacitor. It is highly recommended that you form and test NOS capacitors before deploying them in your application.
  • Recommended Mouser Electronics selections that have been tested and work well with this kit:
    • 667-ECO-S2AP682EA = 6,800uF 100V 35mm Diameter by 50.8mm Long, 2 pin snap in, 10mm lead spacing, Panasonic
    • 667-ECE-T2AP822EA= 8,200uF 100V 35mm Diameter by 63mm Long, 4 pin snap in, 22.4mm lead spacing, Panasonic
    • 661-ESMH101VND103MA6= 10,000uF 100V 35mm Diameter by 63mm Long, 4 pin snap in, 22.4mm lead spacing, United Chemi-con
Click to expand...
Thanks, I really appreciate your help. I'll order the Panasonics. So going from 80v to 100v is no problem?
 
Gepetto

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frhodes said:
Thanks, I really appreciate your help. I'll order the Panasonics. So going from 80v to 100v is no problem?
Click to expand...
Nothing but goodness in going up in voltage rating, if you can tolerate the larger size. Are your original caps 35mm diameter?
 
Gepetto

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BigSkyCory said:
Once I turn the amp off it takes about a second for this to happen. Should I stop using this amp?
Click to expand...
It is likely fine, the amount of energy left in the bulk cap during turnoff is limited to what is left in the cap. The way you describe this is very gradual. You should be able to measure this on a DVM since it is so slow.
 
Gepetto

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The 10KuF 100V caps that I stock are 4 pin on 22.4mm diameter mounting circle.

Is your application a wire in or attached to a PCB?

If a wire in, the mounting circle diameter will not matter. If for a PCB replacement, then it will.

The other 2 pins are just for locating purposes and may be left or clipped off.
 
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