My thoughts on the Llundahl transformers for OTL I mentioned earlier on as a possible upgrade. However good they are I don't think one can achieve 100% dark background unless circuit dampening is used as well. The quality of the tubes is critical no mater what. By quality I don't necessarily mean one needs to spend a lot to get quality tubes. High Frequency AC may also be an alternative for the heater supply.
3/27/15 at 11:29am