arc reference 300's preamp ideas


I recently bought some audio research reference 300 mono blocks and currently have a single ended preamp. Currently Cary SLM-200 mono blocks, thinking about selling them btw, with a mystere ca21 preamp. Awesome sounding combo but time for something new. Need to know best preamp with BALNCED outputs to go with the reference 300’s. My top end is 6k.
andrewnearman
Im open to what ever brand sounds good with arc amps. Ive only had experience with my mystere ca21. It is a very good preamp just no balanced outputs. Thats why im trying to get some suggestions.
Is there any reason that you would get an ARC preamp- there are other balanced line tube preamps out there. The Ref series are some of their better sounding preamps though.