I use to sell these and I don't remember them being very demanding in pre choice. I would think any good tube would work fine. If you see a rebuilt PAS3 Dynaco that might be good as Dave Hafler designed that as well. Otherwise I would look at older models from established companies like CJ or AR. Smaller companies like Blue Circle make good ones also. I would look for the best bargain if I didn't have a specific sound in mind. The matching Hafler 101 was a good pre for its time although it is SS.
