If you hum and it varies at times. It's dc offset on the mains . For the low power of DACs or preamps it's very unlikely to do any harm. Do you need to put your head up to units lol.
We also used the Tungsol KT170set that I had and they were totally lackluster. Granted they were new tubes and never used and has to be factored in but at the end of the day I continued to prefer the KR KT88
Day 1 is in the books
Tomorrow we have countless tubes to roll in including Red Lion Special Edition Genalex KT77, 274B EML etc
Total of 18 guests today kept the demo going all afternoon
We a/b'd the 2 and the Pacific as great as it was lacked the depth, tonality and fullness of the Horizon
We also went direct DAC to amp. In the morning when Lukasz Fred and I listened. all 3 of us preferred the preamp as part of the system. We also went direct to amp at the end of the day and it was so close that I honestly don't know if I could pick out either correctly
I just got back to the hotel from Steve's house. First and foremost, many thanks to Steve and Cathy for putting on a first-class event at their house. It was very well organized and everyone had plenty of opportunities to listen to whatever they wanted to listen to. Second, Steve's system is literally over the top. I can only dream of owning a system like his. Third, thank you Lukasz for creating an extraordinary piece of machinery. My analysis of the Horizon will have to wait until we get back to Arizona as I am taking my bride out for Valentine's Day dinner. Lastly, it was great to meet many fellow WBF members; although I did not get their WBF handle so I am not sure who they are on this site. Thanks Steve!
For the first (5687 pinout adapter to 6n6p), U can use ECC182 (US version is 7119) and 6900. For type 2 pinout (6922 adapter to 6n6p), you can use 12BH7 (best is EH Gold). For type 3 pinout (stock base: ecc81 NO adapter needed) use the Soviets, ie 6N6P or 6N30."