Tube location info: The standard ECC81 is located in V3 and the Balanced ECC81 is located in V6 closest to the power tubes.All Combo amp Retube Kits are shipped with the Eurotubes Double Mica 6L6GC’s at no extra charge. 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. If you choose to go with the JJ 5881's then you may want to use a pair of our EuroDamper rings if you play by yourself or record with the amp. These are available under the "Related Products" tab.