If you fancy something a little more brainless and harder-wearing, I highly recommend Wudtone. Their Black Magic Woman finish is the black for ash. If you dye the ash with a weak blue-purple dye first, to neutralise the natural wood colour, BMW goes on as a perfect black with the grain texture intact. They also sell it with a silver highlight which picks out the grain even more. Their semi-gloss top coat wipes on and is, in my experience so far, about as hard-wearing as a medium nitrocellulose finish, while being a little thinner than most other wipe-on finishes.
A simply dye + any other top coat will work for sure, but for keeping the wood properly protected, Wudtone has become my go-to. Especially with ash, which will pick up any and all marks and stains if it's not given a proper coating of something tough.