The newest Alt-J pre-sale code is now on TMPresale.com. During this Alt-J presale everyone who has the password will have the chance to order tickets before the public. Alt-J presale code for early tickets in San Diego If you don't purchase your tickets to Alt-J's show in San Diego, CA during the presale you might not be able to buy them before they become sold out.
Here are all the Alt-J show details:

Alt-J
Humphreys
San Diego, CA
Apr 19, 2018

Presale
Start: Thu 02/22/18 10:00 am PST

You can use this presale codes and information to get tickets:

Our Presale Passwords are for WiseGuys Members Only -

Join right now and you'll instantly unlock the presale passwords you need to buy your tickets before the general public to this and hundreds of other events

WiseGuys Tip: If a presale password is not found in ticketmaster or livenation - verify that the presale is still valid: you might be looking at a very old post, secondly keep in mind that there might be more than one presale happening - when there are several boxes where presale passwords can be put in you may have to try a few combinations to find the right one.