Tubes are graded better when they are lower noise and more closely matched. It sounds like you only need lower noise.
I would call Kevin, Brent Jessee and Jim McShane and explain your problem. I think any of those three will be honest about whether they have tubes that will solve your problem, within your budget. If they don't, sell the preamp.
I would call Kevin, Brent Jessee and Jim McShane and explain your problem. I think any of those three will be honest about whether they have tubes that will solve your problem, within your budget. If they don't, sell the preamp.