@secretguy +1
I have Primaluna HP mono's & Diologue Premium preamp paired with Wilson Sopia II. I've had no problems. mix & match tubes with no issues and to my ears....they sound magical. Are there better brands, sure...but for the price it's going to be hard to beat. I've had them for 4-5ish years now and have no intention of selling them unless I hit the lottery.