Loud thump !

Guys, my vintage sansui will let out a loud thump when turned on. That made the woofers moved quite strong. Should I be concerned ?

I also experienced the same effect on my Cyrus 1. No damage to my speakers.
I was told it's quite common.

Apparently you can soften or eliminate the loud start up by putting a large value cap across the AC terminals or switch. This mod requires the expertise of an expert as it involves deadly AC voltage.
If you can live with the loud thump, then leave it as it is.

If this loud thump has been in existence since the beginning, then it shouldn't be an issue. But if it has only recently appeared, then you will need to have it checked.

Perhaps later I'll send for checkup. Thanks.

Hasnul,
Good solid state amplifier design employs circuitry to eliminate the thump. Either a soft start in the power supply or a DC monitoring system at the speaker outputs.

Sph,
I also used to own a Cyrus 1 and 2. While they don't have DC monitoring sytem at the output nor a soft start, during turn on I usually see a small movement on the woofer; that's about it. If it thumps I think perhaps the power caps are about to give way.

cheers.

? I thought this is quite common for vintage design. as most doesnt have relay in place yet. If last time dont have, but now u have it.. maybe the relay inside is permanently on already.

haha, my exposure amp thump and tack to my speaker every time I on and off it. It is infact an uncompromised sonic approach...less contact, more direct connection~~. though some of you may not agree~

adrian4454 wrote:
haha, my exposure amp thump and tack to my speaker every time I on and off it. It is infact an uncompromised sonic approach...less contact, more direct connection~~. though some of you may not agree~

That's precisely what smart marketing does... it cleverly covers downfall of a design "kononnya" for sound improvement... In actual fact they are cost cutting by removing vital items in the amplifier.
Switch on thump can be solved by installing an output relay with delay on, switch off tack can be solved by installing a 240V rated X capacitor on the power switch.

cheers.

Hmm.. I dont think Exposure 2010s2 will do that just to save around RM10...

Anyway, maybe you are correct~

adrian4454 wrote:Hmm.. I dont think Exposure 2010s2 will do that just to save around RM10...~

RM10 is from our consumer's point of view...

From manufacturer's POV it's :
it's RM10 x XXX units = $$$$$ savings for the model ....


cheers.