If you want to play Irish tunes on a blues harp you have the problem of the missing 6th note in the lowest octave to contend with. As it stands, this puts rather a large minority of tunes out of reach. You can solve the problem by doing the retuning yourself, or by paying out a wad of dosh for a customised instrument from Brendan Power or someone of that ilk (you get a very fine instrument too). But I’ve just discovered a chap in the south of England who will sell you a perfectly set-up Hohner harp, to your tuning specifications, for very little more than the shop price of off-the-shelf harps. He’s Antony Dannecker and his site is http://www.southx.biz/dannecker/home.htm I suggest you email him first to tell him what you’re after, or even give him a ring. You do need to be able to articulate your requirements very clearly, as with any instrument customiser. He’s not an ITM specialist. I’m happy to discuss this aspect offlist with anyone. He only deals with Hohner instruments, so no Lee Oskars. I’ve just got two Special 20 low Ds from him that he retuned to Paddy Richter for me and fine-tuned to equal temperament, for which I paid £21 each. I have no affiliation to him whatsoever, and I know this whole post sounds like an ad, but I mention him because I think that he would be genuinely useful to aspiring ITM harmonica players who are both impecunious and reluctant tinkerers, i.e. most of us.
I get lots of requests for info about this stuff all the time, and I think it’s definitely worth saying that this service exists. If I’ve breached list guidelines on commercial posts here I haven’t done it on purpose, there’s nothing in it for me, and would appreciate if someone wrote to me quietly about it, in which case I shall promptly delete the post!
Steve