Please can someone tell me which preamp tubes (brand and exact model type) an SVT-4 Pro is supposed to leave the factory with? I've just re-mortgaged my house to buy one, only to find that it has 1 x Groove Tubes 12AX7R and 2 x Electro Harmonix 12AX7EH tubes in it. That doesn't look right to me! Do I need to go and slap the guy who sold it to me as "NEW" (****ing eBay) , or has he done me a favour? (Seriously, I need to know if a new one would come with two different brands of tube in). More importantly, which of the Groove Tubes models would best suit this preamp for an authentic SVT "growl" tone? Are the 12AX7Ms (Mullard copies) worth considering, or would they be too mellow to overdrive? All opinions welcome!