Hi Stephen,
Do you believe your ranking is being affected by spammy/low quality or artificial links? Are you jumping on the disavow tool for a reason or is this a pre-emptive measure? Have you considered or tried to get any links that you are concerned about removed manually?
Google recommend that you use the Disavow tool only if:
1. your believe you have a considerable number of spammy, artificial, or low-quality links pointing to your site
2. your confident that your site's performance in the search results is being harmed
DA alone isn't going to tell you which sites are spammy, artificial or low-quality. As Chris mentioned you'll need to take a broader view and look at the linking pages, their link profiles, the anchor text they're using their relevance to your site. (If someone said, hey I saw your link on site x, how would you feel about that?)
A link doesn't just provide authority, but also relevance, both in it's anchor text and context. You'll need to look at how natural these are, not over-optimised exact match/site wide/keyword anchor text and from a legitimate site as far as Google and your customer/audience are going to interpret it.
Just because a site has low DA, doesn't mean it's a bad place to get a link from! Some markets/niches are very small. Sites in that niche may be likely to have few links BUT they attract a highly relevant audience. While a link from one of these sites may do little to boost your domain authority it may give you some great exposure and drive a small amount of highly relevant (or high intent) visits to your site.
Make sure you know which links are passing you traffic. After all, we're not really here just for the rankings, it's the traffic we're after. You don't want sever the link that's passing high value visitors/customers.
Look at the back link profiles of your competitors (not just one or two) to get a feel for what is natural in your market/niche. Don't just look at the top ranking sites though as this can give you a skewed impression. Look at those businesses that are (respected) business competitors - not just the ones that are competing at the top of the SERPs.
As EGOL says, build great content (or offerings) and if you're going to build links do it to promote your content to your target audience.
You might also find this article on Link Profiling of interest:
Link Profile Tool to Discover Paid Links or Other Anomalous Linking Activity
And one final point - Domain Authority is just a Moz metric, it's only ever going to be an estimate how Google views the "link equity" of a site.