Loudspeaker thump

[tomat]

loudspeaker thump when amplifier turn on,what causing them? and how solve that?
thanks for the help

[destroyer X]

you have , mainly into the differential pair long tail causes that...also others, alike bootstrap and second differential transistor does that.

The higher the resistances value you use together a high capacitance, then your time to load will be big too... and this takes time to stabilize (charge) and you will see the amplifier going to stabilization into the ouput line with your speaker movement.

Reduce long tail capacitors, use something that loads at ligth speed alike active devices..i use zener in my amplifiers.

regards,

Carlos

[tomat]

thank you very much for the help,i will try

[paulspencer]

It can come from a number of different components, but most hifi amps will have a relay which mutes the outputs for around 5 seconds on powering up so that any thumps which may come from the amp or anything upstream won't come through.

[destroyer X]

the spike produced when you switch power on can be sensed by the amplifier and produce noises..not exactly what is considered power on "thump" but produces noises, sometimes have high and low frequencies together...a thump mixed with a "paft!"

Having that, include, increase value to 10n, or substitute your power on switch key capacitor.

I often use the one available, the high voltage one, between 10n and 27n

regards,

Carlos

[tomat]

Originally Posted by destroyer X

you have , mainly into the differential pair long tail causes that...also others, alike bootstrap and second differential transistor does that.

The higher the resistances value you use together a high capacitance, then your time to load will be big too... and this takes time to stabilize (charge) and you will see the amplifier going to stabilization into the ouput line with your speaker movement.

Reduce long tail capacitors, use something that loads at ligth speed alike active devices..i use zener in my amplifiers.

regards,

Carlos

Hi Carlos,
some time we see an amp using opamp ic on input stage,how if this happen on there

thanks