So I have now been listening to music for about 2 1/2 years with my Latino built VTA ST-120 and so far for the most part things have been good. I started out with the Sovtek KT-88's that I bought with the amp and then tried out Tung Sol KT-120's last October. About a month ago I was looking to try a different tube and after a few emails between myself and Jim McShane I went with his recommendation of Genelex Gold Lions. As soon as I took one out of the box I noticed that it looked a lot nicer than the previous thanks to the printing on the glass tube and base color. I finally decided to try them out today. I installed them and set the bias. Here's where my question comes in. The other two tubes had no problems with biasing to .550 VDC however upon a recommendation bumped that down to .500 VDC to prolong the tube life and keep the transformers cooler though I can't substantiate the tube life issue. When biasing the Gold Lions every time I tried setting the bias for higher than .410 VDC or so my Fluke 85 would alarm out. So I set the bias to .400 VDC and decided to try them out. They sound quite good being brand new. Even though the bias was lower I still turned the attenuator down a few steps and the dynamics are still there. I have my Cary SL-100 preamp set to about the same volume level as before.
Do you think anything is wrong with the tubes? Does only being able to bias them to .400 VDC mean they will have a shorter life than the other tubes?