Hi guys, Welcome to the Advanced Video Search Engine, and you are watching Once upon a time, there were METAL tubes. metal 6L6 performance test w tube checker and amplifier. That video is uploaded by Young Ahn at 2019-12-09T06:00:36-08:00. We are promoting this video only for entertainment and educational purpose only. So, I hope you like & enjoy it. [ktgGv26QHuU]