Increasing Wattage?

I have a Yorkville XM50 Bass Amp and I would like to increase the output of the amp if possible. I'm curious as to if it's possible and how one would go about doing it. Thanks.

You basically build a new amp from scratch - power output is dependent on the supply voltage and the speaker impedance.

If you were lucky, the 50W amp might be 50W in 8 ohms, with a 100W version of it giving 100W in 4 ohms, in which case rthe amplifier will have space for an extra pair of output transistors, and a larger mains transformer. I have a 60W Fender keyboard amp that's like that, with a 100W version available.

Of course it's possible, just not very practical. Here's what you'd be starting with:
https://www.electro-tech-online.com/custompdfs/2011/08/smxm50.pdf
and here's the 100W version
https://www.electro-tech-online.com/custompdfs/2011/08/smxm100.pdf.

Alright, thanks

100W sounds only slightly louder (+3dB) than 50W because the sensitivity to loudness of our hearing is logarithmic, not linear so we can hear a HUGE range of loudness.
500W sounds twice as loud as 50W.