The Balanced ECC83S is located closest to the power tubes in V2.The default power tubes are the JJ 6L6GC's and all our combo amp kits which use the 6L6GC's are shipped with the special Double Mica 6L6GC’s at no extra charge which will greatly reduce any tube rattle. JJ Electronic started building us a proprietary version of their 6L6GC (the 6L6GC-DM) in 2005 with extra layers of mica. This reinforces the plate structure and all but eliminates tube rattle symptoms. For all other tubes such as 6V6S's, E34L's, EL34II's, EL34’s, KT77's and 6CA7's, we recommend using our EuroDamper rings. These are available under the "Related Products" tab and will greatly decrease tube rattle.