Hi, i was at the Stereophile show last weekend. They had this nice ASL Tube amp on the Reference 3A speakers. I think the tubes were either 2A3 or the 300B tubes. But this Tube Amp looked really good. The system sounded great. Plus, I also heard that ASL headphone amp. Its lists for like 1200 dollars. It also can be used as a preamp. It uses 2A3 tubes and other tubes. This headphone amp sounded amazing. It was very smooth sounding and could go loud. When you listened to the ASL headphone amp, you heard them threw the tubes and the transformers weren't in use. I think the Transformers are used when the ASL is used as a preamp.