You have a very nice little system already. The A3 is a great choice. I had a Jolida 1701a for a while and thought it was good but lacked resolution. Your speakers would make that too obvious I think. The A3 won't have that problem.
As S7horton says, the Audio Refinement Complete is very very nice. But if you want to get into vacuum tubes (which I highly recommend), the Consonance Cyber 100 that is up for sale here would be a great choice. I have no connections with the seller. I am very familiar with the Consonance M100 Plus - it was a super nice amp for the money. Unless you really like music loud, a 40W tube amp would work great.
Arthur
As S7horton says, the Audio Refinement Complete is very very nice. But if you want to get into vacuum tubes (which I highly recommend), the Consonance Cyber 100 that is up for sale here would be a great choice. I have no connections with the seller. I am very familiar with the Consonance M100 Plus - it was a super nice amp for the money. Unless you really like music loud, a 40W tube amp would work great.
Arthur