2. speakers
  3. 185537-91149

Woofers pumping

On two occasions I have noticed the woofers of one speaker moving 1/2 inch excursions. Both times the SPL was peaks of 93 dB.

System is CD player, preamp, amps.

This has happened with two different amplifiers.

I spoke with the tech at B&W and he didn't have an answer.

tomcarr
erik_squires
16,719 posts
 

If the pumping you describe was slow, and it’s a tube preamp you may have a leaky coupling cap. Needs to be replaced. More dangerous with DC coupled amps.

If the woofer pops in or out and slowly returns to a center position, it's likely another cap in the circuit. The coupling cap eventually charges to DC and blocks it.

tomcarr OP
1,640 posts
 

@audionoobie LOL!

@erik_squires No. Topping Pre90

erik_squires
16,719 posts
 

If it's solid state, this may happen with an intermittent regulator.  You may lose a + or - rail, but the coupling cap will eventually compensate for it.  Maybe. :D

tomcarr OP
1,640 posts
 

@erik_squires Thank you for the info. I'll contact Topping and see if I can get any info. What really surprised me was the tech at B&W didn't have any idea what could cause it to happen!!!

tomcarr OP
1,640 posts
 

I called B&W again today hoping to be able to talk to a different tech.

Apparently, there is only ONE tech, and he isn't any help at all!!!

More to discover