I don't think I've written much about it. It was a commissioned design. I wanted to use a driver is the family of the 6SN7, the 71A as a power tube, TL404 outputs and it was originally designed as a headphone amp (and still can be). In the beginning it had a second set of output transformers to drive Stax headphones. The driver can be swapped from a single 6SN7 or use two 6J5, 2C22 or with a converter, 7A4. I really don't listen to headphones much so it spent most of the first few years as a preamp. I used a Magnequest Ingot replica in front of it to drive my 300B power amps. The new BeePre edged it out of that spot and this is the first time I've used it as a power amp. I was surprised that it can drive the speakers to uncomfortable levels without clipping. The gain from the Eros and BeePre had to factor into that. The amp barely gets warm and the tubes are cheap. There are not a lot of speakers that it would work with and I count myself lucky that it does with mine.