2. amps-preamps
  3. 176074-89448

Woofer pulsating with no volume , Oscillation issue?

Hello all - I just picked up some new Harbeths and as I was listening I noticed the left woofer moving kind of peculiar....I turned off my source & the woofer was actually pulsating in & out with no source volume. 

I have Manley Snappers . I switched sides (speaker cables) with no input & the problem followed to the other side....must be some kind of amp oscillation issue Im guessing...? Thanks for any troubleshooting help- 

128x128tommypenngotti
erik_squires
16,173 posts
 

It sounds like a bias/offset issue.  I'm not a tube head but contact the manufacturer or your dealer.

tommypenngotti's avatar
tommypenngotti OP
219 posts
 

@erik_squires

ya , the left amp has a bias reading all over the map , should be 300 & its jumping radically...did contact Manley about all this, looks like it's headed back to the shop.....thanks

blackdoghifi's avatar
blackdoghifi
45 posts
 

It could be nothing more than a bad tube. Try swapping them left for right first.

Start with the power tubes.

If it doesn’t follow the tubes, then most likely needs service.

I should add, the woofer pumping, and the bias bouncing around are most likely related.

 

 

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