I have not been able to locate a matched quad of Groove Tubes GT-6CA7-GE. Only the GT EL34-M is currently available, and even some of these are now being sold by new GT owner Fender with stickers on the glass rather than the original imprinted orange GT logo and numeric information. I have a question for you since you've used Groove Tubes: The tubes come in rating ranges from low - mid - high. Seems everyone selling GT's has a different answer on which rating range of GT's to buy for audio HiFi applications. No consensus at all. What rating were your GT's? One HiFi buyers conundrum with tube reissue purchase is that most resellers are coming from the guitar amplifier world, not from the audiophile world. Nothing quite like the classical/jazz audiophile being asked by the reseller if they want their tubes for "the Van Halen sound"?