Velleman PA100U portable ampli

Very Nice Amplifier ,
I use it with a Stratocaster and it sounds really fine
but
I need to have some caracteristics about the loudspeaker size,model,ohms,watts;etc because I want to change it for better bass expression.( it vibrate somehow strongly when bass tab is after middle position.)
before unscrewing it ,I should like to know if you have those informations
thanks for answering
kind regards

You should post your question in the following link
http://www.velleman.eu/support/contact/?product=386062