I can only hear differences between caps on the extreme end, usually 716p OD's compared to Sozo's, the sozo's sound a little less harsh and a bit more vintagey. 

If you want to spend even more money on the amp then check out the PIO jensens, there's also the mallory electrolytics

Don't forget about RV4 pots while you're at it

You can leave it out to get it up and running


I think it has something to do with the pots taper? 

Edit: never read the post so it was flagged as 'new'