Im wondering which amp is better with the HE-400 and ODAC.
I currently have the c421+ODAC and planning to purchase the HE-400.
What kind of difference will i hear with the Asgard or O2 compared to the c421? Is there a need to upgrade it?
I cant afford what i believe would be perfect for me HE-500 + Lyr + Bitfrost. So im trying to get close with HE-400+c421+ODAC. I need to c421 for my iPhone+re262 so will need to keep it even if i buy the O2 or Asgard.
Any other recommendations not too expensive?