Tube location info: The Balanced Gold Pin ECC83S is located in V4 and the standard ECC81 is located in V7. The three standard Gold Pin ECC83S's are located in V1, V2 and V3. The non-Gold Pin ECC83S's are located in V5, V6 and V8.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.