This is our Tweed Option Retube Kit for the Ampeg GVT15. It contains a premium matched pair of JJ Electronic 6V6S's, a JJ 12AY7 for V1, and a current balanced ECC83S for the phase inverter in V2. The Tweed Option will drop the gain down a bit more than the SRV Option allowing you to get more power tube breakup at higher volumes. The JJ 12AY7 has a fat warm tone with a big shimmering sparkle in the high end!