Txs for a tip Stephan. As I said I haven't heard them in the DAC yet, so don't have my own view on that. But I heard them in the Klangfilm amps which my friend John restored for somebody and those amps were just brilliant. Sadly he didn't want to sell them to me ;( Also I liked the way their chassis were made, boxes to hung on the wall, behind the speakers for super short connection and almost invisible "being in the system". I fully agree with you on the sonic quality in the amps. Unforgettable experienceThe F2a/ 11 is a shame for a Dac, that tube belongs in a Telefunken V69 amp or Klangfilm amp. there it unfolds its magic