thump on speaker...how to avoid it?

[Stefanoo]

Hello guys,

i was just thinking about different ways of handling the thump on loudspeaker when your amp/pre is switched on and off.

The classic way and i guess the more common one is to use an integrated circuit that controls the DC as for example TA7317P which it drives an output relay.

This is also the only way I personally know.

Although i think it is very easy to implement, yet it might be not the best in term of quality, since the output signal is vinculated to pass through this relay.

What other ways do you guys know ad use on your own projects to deal with this thump beside the above mentioned?


Hope this is an interesting subject.


Best,
Stefano.

[Babowana]

I tried this:


http://www.passdiy.com/pdf/zenlite.pdf Fig.14

[Stefanoo]

any other ideas?

[wuffwaff]

Hi,

the relay to ground is quite nice cause the signal doesn´t have to pass the relay. You just can´t use it with every amp.

With all the amps I´ve build the turn on/off thump never really has been a problem. I don´t use any relays.

Worst is my Aleph5, then Aleph-X then Crescendo. With the Aleph 5 you can hear but mostly see the turn off as the woofer moves. With the other 2 there´s nothing to hear or see.

I always turn off the power amp first, this way there can only be one thump....

So I would suggest to just ignore the thump (cough while turning you power amp on or off )

William

[Stefanoo]

nice idea: moving the relay to ground...i guess that not all the amp can handle a short for a couple of seconds.

Well....if you say that the Aleph X doesn't have Thump at all...nice!
Since i'm going to build that one in the next months or so, it is a good news.

I opened up this 3d when i was repairing an Electrocopaniet integrated amp (very nice sound).
For the sake of the consistency i was testing it before the relay and each switching on/off was a tragedy for the poor woofers of the test loudspeaker (i would have never hooked it up to my B&W 805).

when finally i fixed the protection ciruit and everything was finally ready to go........i thought of different ways of manage this thump on amps that need something to avoid a dangerous peak on the speakers.
I don't know if there are more refined way of doing it.

I'm curious to know and i'm looking forward to see different solutions.