[fbleagh]

I'm building a kit i picked up from jaycar here in sydney and was wondering if i could swapout the opamps supplied for some better ones

TL071 and TL072 are the opamps they supplied, is there anywhere i can look up what opamps are pin and function equivalent ?

BTW these aren't for headphone use but for a guitar preamp

as i am trying to learn the bass.

 

[Budgie]

Sometimes the website of the manufacturer will have a cross referance search engine, but the results are not always great. They tend to cross to chips with the same specs, but usually there will be a number of chips with the same pinout, but better specs, they won't tell you about. Luckily, the chips you listed are the most common pinout, so there are lots of chips you could use.
I would start by printing spec sheet for the chip they supplied, so you have a starting point, then look for chips with the same pinout but better specs. I just finished using about a dozen OPA 134 series chips, with good result, in a couple upgrades to existing designs. A good starting point would be to hop over to Headwize and read the library article by Chu Moy on designing with opamps.

http://headwize.com/projects/opamp_prj.htm