Curious about this myself as I am looking to do this upgrade.   Found this thread about it. http://www.head-fi.org/t/540541/good-opamp-for-a-ht-omega-claro-halo-using-grados   Looks like you do indeed need 2 627's for 8 or 10 since they are mono. And you do need to use an adapter such as...

Quote: Dammit....I knew I should have bit.

I am curious as well where you found that price. I saw a sale a few months ago for $457 buts that's the lowest I've seen.   Really want a pair of these.