I have a half dozen of them in each price range. The only one I thought was terrible was the Sovtek. Sounds like they used rusty iron plates and pumped the exhaust of an old school bus inside 'em rather than pulling a vacuum. All the others I have sound good.

My favorite is an RCA, second favorite is GE. Electro-Harmonix is nice too. Tung-Sol doesn't do anything weird, sounds good. All these are new production but the RCA and GE, all used in an Audio Note Kit 2.

I'm thinking about trying a Telefunken. Your thoughts?