Yikes! I need the experts help with this issue

[spider_duggan]

Okay, here's the issue. When I turn on the amplifier/reciever, the speaker cone pump in and out like a jackhammer, only once. No audible noise other then a little 'thump,' but the two speaker cones must be moving to there limits.

If the volume is turned all the way down then the speaker movement is less and the thump if less audible. If the volume is at 15% then the cones jump out and the thump is noticible.

Here's the gear.

Monster low end power bar
Rega Brio http://www.rega.co.uk/index2.htm
Rega P3 http://www.rega.co.uk/index2.htm
B & W CM4 speakers
Kimber Kable speaker wire
R-L analog RCA cables from P3 to Brio

That's all.

So, why the thump and the cone movement? Can this be fixed if it's not normal with this gear? I've never seen it happen on another system, so that's why I'm asking about it.

 

[t3031999]

According to page 5 of the manual for the Rega Brio amp.

At turn
on an audible thump may be heard through the speakers, this is
normal. WARNING: Never switch the amplifier on with the volume
control set at or near maximum

So I guess that is normal. Just have the volume way down before turning it on.

 

[jaxvon]

It's a flaw in the amp design. Rega didn't put in relay to mute the output. All amps would do this if they didn't include circuit to shut off the output during power up. The thump is from a small surge of power being outputted by the amp.

 

[spider_duggan]

Thanks

Yep, that answers it. Thanks.

I'm not sure I like it.

Dan