Low Cost DACs


Currently I have my laptop connected directly via 1/8 jack from headphone outlet into 2 RCAs directly into my tube amp. Quality of sound is lacking to say the least!
I am considering adding an inexpensive DAC ( iFi AUDIO nano iDSD LE Portable DAC  or iFi Audio nano iOne DAC ) into the stream between the laptop & amp.My question is: will this influence the overall sound I'll hear out of my speakers? Will adding such a DAC help to increase the quality of sound produced by the system?
I'm not interested in spending a lot of money on a DAC as this is a source that I don't use as much as some others already in the system.
wcc10
I'm using the ifi nano LE to my preamp and I'm very happy with it. I have a Schitt Modi Multibit and a Nixon dac I like to try affordable dacs to see what I like but I'll never be a player in the >$1000 range so these will have to do. The thing they all have in common is they're musical and they're paid for.
I've always liked Analysis Plus cables, not all that expensive but very good build quality. Signal Cable too.
I switched from a generic USB data cable to an AudioQuest ‘Cinnamon’ cable $80 and noticed a drastic improvement in sound quality. 
To be honest, I had a pair of MIT "Terminator" speaker cables which were good. but am now running AudioQuest spooled 14 AWG "Zip" cables and never been happier. I'm sure their USB cables are very good!