I picked up the IHA-1 after deciding I no longer liked my wallet. Getting into tube rolling will certainly slap it around a bit. I went with the Lundahl transformers since those that suggested the IHA-1 to me deemed it a requirement. The included tubes were the Sovtek 5Y3GT and two Tung-Sol 6SN7GTBs.
The plans for the near-future are a Linlai E-274B and a pair of Linlai E-6SN7s. I almost went down this rabbit hole when I had the Woo Audio WA22, but that was a bit much for me at the time. Now that I've settled on my top 3 headphones going foward, I can focus on other aspects of sound that escaped me early on.
You can read our in-depth review and tube rolling analysis by Flux: