My woofer is thumping (not when I want it to)

RSBosma · 13th April 2007, 03:13 PM

Folks,

Newbie question here. I have a plate amp that I'm using with a 10" titanic (both from Parts Express) in a small sealed enclosure. My problem is I have a thumping noise that occurs at a very low frequency. It coincides with the output of the mains and center, meaning it only happens when there is sound coming from them. It is thumping at most about 3-5 time per second. It is erratic and definately not in the signal as it happens all the time no matter the source. Any ideas, it's driving me crazy.

Thanks,
Ryan

Jan Dupont · 13th April 2007, 03:19 PM

Thumping at 3 to 5 times per second (3 to 5 Hz)

Seems like you maybe got a bad plate amp

AndrewT · 13th April 2007, 03:38 PM

Hi,
there was another very recent thread that confirmed feedback through the speaker level inputs was causing the low frequency thumping.

Jan Dupont · 13th April 2007, 03:40 PM

I have missed that

Interesting subject

RSBosma · 13th April 2007, 04:16 PM

I'm running my input at line level. I thought it might still be a ground loop problem though, is it worth it to go buy a cheater plug?

RSBosma · 13th April 2007, 04:23 PM

Is this the way a ground loop manifests itself in a sub, by making a thumping sound?

AndrewT · 13th April 2007, 04:28 PM

A ground loop usually results in hum at the speaker/s.
Sometimes it's hum and buzz depending on how badly the grounding error is.

RSBosma · 13th April 2007, 05:59 PM

Andrew,

Well....that's what I thought. So, any ideas on any other possibilities. The plate amp has worked faultlessly for 3 years and is now set up in my new home theater in our new home so as far as changes go, this is the only change made since it was set up in my old house. By that I mean it was just set up exactly as it was configured before, wire for wire.

Thanks,
Ryan

Netlist · 13th April 2007, 06:15 PM

During the transport, a part came loose. Big power supply caps have a bad reputation to do that.

Just a thought.

/Hugo

13th April 2007, 03:13 PM	#1
RSBosma diyAudio Member Join Date: Aug 2006	My woofer is thumping (not when I want it to) Folks, Newbie question here. I have a plate amp that I'm using with a 10" titanic (both from Parts Express) in a small sealed enclosure. My problem is I have a thumping noise that occurs at a very low frequency. It coincides with the output of the mains and center, meaning it only happens when there is sound coming from them. It is thumping at most about 3-5 time per second. It is erratic and definately not in the signal as it happens all the time no matter the source. Any ideas, it's driving me crazy. Thanks, Ryan

13th April 2007, 03:19 PM	#2
Jan Dupont diyAudio Member Join Date: Apr 2003 Location: Copenhagen, Denmark	Thumping at 3 to 5 times per second (3 to 5 Hz) Seems like you maybe got a bad plate amp __________________ Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com

13th April 2007, 03:38 PM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, there was another very recent thread that confirmed feedback through the speaker level inputs was causing the low frequency thumping. __________________ regards Andrew T.

13th April 2007, 03:40 PM	#4
Jan Dupont diyAudio Member Join Date: Apr 2003 Location: Copenhagen, Denmark	I have missed that Interesting subject __________________ Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com

13th April 2007, 04:28 PM	#7
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	A ground loop usually results in hum at the speaker/s. Sometimes it's hum and buzz depending on how badly the grounding error is. __________________ regards Andrew T.


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13th April 2007, 04:16 PM	#5
RSBosma diyAudio Member Join Date: Aug 2006	I'm running my input at line level. I thought it might still be a ground loop problem though, is it worth it to go buy a cheater plug?

13th April 2007, 04:23 PM	#6
RSBosma diyAudio Member Join Date: Aug 2006	Is this the way a ground loop manifests itself in a sub, by making a thumping sound?

13th April 2007, 05:59 PM	#8
RSBosma diyAudio Member Join Date: Aug 2006	Andrew, Well....that's what I thought. So, any ideas on any other possibilities. The plate amp has worked faultlessly for 3 years and is now set up in my new home theater in our new home so as far as changes go, this is the only change made since it was set up in my old house. By that I mean it was just set up exactly as it was configured before, wire for wire. Thanks, Ryan

13th April 2007, 06:15 PM	#9
Netlist diyAudio Moderator Join Date: Jan 2003	During the transport, a part came loose. Big power supply caps have a bad reputation to do that. Just a thought. /Hugo

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