Sylvania 6AS7G 6SN7GTB tubes for Dark Voice/BottleHead Crack/Eufonika/Xduoo amps

Rare Vintage Sylvania 6AS7G and 6SN7GTB NOS tubes for tube amplifiers such as Dark Voice 336SE, BottleHead Crack, Eufonika H5, Xduoo TA-26, Woo Audio, Feliks Audio, and so on. NOS Sylvania tubes are great sounding tubes, famous for their neutral sound with slight warmth. The Sylvania 6AS7G tube has the typical yellowish Sylvania print on the base, and has a foil-strip square-getter on the top. As with all one-sided foil-strip getter or 45-degree square-getter, getter flash is normally shifted to the side which has the foil-strip, and the other side may have some place without getter flash. This 6AS7G is no exception. But it is normal. Tubes are tested on our military TV-7D/U mutual conductance (Gm) tube tester, which was recently restored and calibrated by Dan Nelson – the King of TV-7 series tube tester restoration and calibration. TV-7D/U test results (also refer to photos for measurements): Sylvania 6SN7GTB Gm: 100 / 94 (minimum good = 50) Sylvania 6AS7G Gm: 62 / 60 (minimum good = 36) * Minimum good for 6SN7GTB tubes on TV-7D/U is 50 (65% of NOS), so Below 50 = Low testing tubes 50 – 77 = Good tubes 77 and above = NOS tubes * Minimum good for 6AS7G tubes on TV-7D/U is 36 (65% of NOS), so Below 36 = Low testing tubes 36 – 55 = Good tubes 55 and above = NOS tubes So these two tubes are very strong, way above the NOS level. No shorts, no leakage, no gas. Tubes also have been sound-tested on our modded Dark Voice 336SE headphone amplifier. They sound fantastic, no microphonics, no hissing / crackling / or other noises. Background is dead quiet. Tubes come with generic white boxes. Shipping: Tubes will be shipped by Canada Post Small Packet by Air, unless otherwise specified. It normally takes 5 – 10 days to get to US addresses (2 days within Canada, 1 – 3 days to cross the border, and 2 – 5 days within US via USPS Priority Mail). Shipping fee to Canadian addresses is US$15. Combined Shipping is welcome, if multiple items are purchased. If items have been paid separately, we will automatically refund any savings from Combined Shipping. International Buyers – Please Note: Currently, these tubes are ONLY available to folks in USA, Canada, UK, Ireland, Germany, Austria, France, Switzerland, Belgium, Netherlands, Sweden, Norway, Denmark, Iceland, Finland, Australia, New Zealand, and Japan. Folks in other countries please inquire first before hitting the BUY button. No shipping to China, India, Indonesia, Vietnam, Italy, Russia, and so on due to lots of reports on lost packages at customs. Return Policies: Returns will be accepted within 14 days of delivery, provided tubes are in their original conditions – no damages to tubes, factory tube boxes (if there are), or print on tubes; no drops in tube mutual conductance (to prevent abuse); and no removal of our unique stamp on tube glass. Buyer pays for the return shipping cost. Our purpose here is to sell tubes instead of loaning tubes for rolling. To discourage tube trial there will be a 10% restocking fee. Serious buyer only! Please contact us first before initiating a return to discuss concerns and solutions. All our tubes will be imprinted with our unique stamp on the glass. Please do NOT remove the stamp, or else tubes will not be considered ours and return will be denied.