Need Help With Desktop Audio System

[SuperShermanTanker]

So currently I'm using a old Sony stereo system that has no AUX jack plug as a imput to plug the PC into the unit and instead I'm using a cassette adapter (one of those ones with the 3.5mm headphone jack wire coming out of it) for getting the PC to hook up to the stereo system. Now I want to replace this system which is a very old system with somthing newer and will still allow me to use my 40watt AWIA speakers does anyone know of a little hub or audio unit that will allow me to hook up my pc to it using a 3.5mm headphone wire and will be able to power my 40 watt speakers that use this connector 

[spwath]

Budget?
 

$30

https://www.amazon.com/Lepy-LP-2024A-Amplifier-Stereo-Supply/dp/B00ULRFQ1A/ref=sr_1_1?ie=UTF8&qid=1467489276&sr=8-1&keywords=speaker+amp

 

$70

https://www.amazon.com/SMSL-50Wx2-TDA7492-Amplifier-Adapter/dp/B00F0H8TOC/ref=sr_1_1?ie=UTF8&qid=1467489314&sr=8-1&keywords=smsl+speaker+amp

 

$120

https://www.amazon.com/SMSL-Digital-Amplifier-Coaxial-Optical/dp/B019SLU1D2/ref=sr_1_5?ie=UTF8&qid=1467489338&sr=8-5&keywords=smsl+speaker+amp

 

And this new, cute tiny 130$ one with bluetooth

https://www.amazon.com/SMSL-Bluetooth-Digital-Amplifier-Stereo/dp/B01FHAYWXI/ref=sr_1_9?ie=UTF8&qid=1467489338&sr=8-9&keywords=smsl+speaker+amp

 

[southpaw516]

+1 for Lepy. I upgraded from an old stereo to the one below. I got this instead of the one @spwath linked since it is 2.1 so I can add a sub later.

 

https://www.amazon.com/gp/product/B01AQARWHW/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1