Sound Ideas Stereo "North Florida's Audio / Video Choice Black Plate audio tubes made in USA; 1956-59 These tubes were tested with a B and K 707 Dynamic Mutual Conductance Tube Tester that was calibrated in 2013 and the"5687" tubes all tested great with matched sections; 98-93, 98-96, 98-95 and 99-98, lot M. 0 to 55 Replace. Tube is near, or at, the end of its life rating 56 to 64. At 65 to 70 tube generally is operational, but could be replaced, with 75 to 120 great. Different tube types have different average readings. NOS tubes average 70 to 95. Tube Description: All tubes are the same matched construction Manufacturer: Made in USA by Tung-Sol Black smooth plates with two holes Four copper grid posts “D” or horseshoe getter rings The following tests are performed on each tube: SHORTS test: Tubes are tested for inter-element shorts. The test for shorts between elements is made to a sensitivity of approximately 1 megaohm. Tubes that fail this test are rejected. GRID EMISSION test: Tubes that indicate grid emission are rejected because they often noisy. MUTUAL CONDUCTANCE test. This test is the most accurate and inclusive single test that can be made on a tube. The amplification ability of a tube is governed by its mutual transconductance performance. There are three MUTUAL CONDUCTANCE measurement regions indicated on the tube tester. 0 to 55 Replace. Tube is near, or at, the end of its life rating 56 to 64. At 65 to 70 tube generally is operational, but could be replaced, with 75 to 120 great. Different tube types have different average readings. NOS tubes average 70 to 95. This is our third eBay seller's account, we have a long history on eBay, check our other user name's 100% positive feedback "soundideasflorida" with over 1000 pos feedbacks and zero negatives. Here is a link to our other store: http://myworld.ebay.com/soundideasflorida Check our feedback and bid with confidence!! -------------------------------------------------------------------- Revised shipping policy as of September 20, 2005. Due to items lost or damaged in shipping, any item over $50.00 in cost will require delivery confirmation and insurance for the sale amount. It is unfortunate that this is necessary but experience has proven it is well worth the small extra cost. We apologize for this, but it is for the good of all involved. Any item may be returned within 15 days of purchase for a full refund of the purchase price, not including shipping, providing it arrives back at our store in Florida in the same condition as sent, unless otherwise stated in the ad. International purchases need to be returned with incoming custom's duty prepaid, if any. Any postage or import duty that is due upon arrival will be deducted from the refund. 15% restocking fee on all returns unless defective or "not as described" Our reputation is very important to us. If you would like to check our feedback rating you will find all satisfactory transactions with no negative results. We still maintain a 100% positive feedback rating. TERMS: All listings are plus shipping unless noted. 6.00% sales tax added to all In-Florida destinations. This unit is guaranteed to be in "as described" working condition (unless otherwise noted) upon arrival and has a 30 day limited warranty, baring any abuse. PAYMENT or payment notification expected within THREE business days of invoicing. We accept PayPal, credit cards, or cash if local pick-up. SHIPPING: We ship internationally on smaller items . Domestic packages are shipped via Fed Ex. Small items (such as vacuum tubes) or international packages shipped via USPS. All shipping quotes will include insurance and delivery confirmation. Shipping charges reflect actual cost of shipping, plus a nominal fee for packaging materials. Items are very carefully packaged for shipment. Items ship from 32609 in Gainesville, Florida. RETURNS: Any item may be returned within 15 days of purchase for a full refund of the purchase price, not including shipping, providing it arrives back at our store in Florida in the same condition as sent, unless otherwise stated in the ad. International purchases need to be returned with incoming custom's duty prepaid, if any. Any postage or import duty that is due upon arrival will be deducted from the refund. 15% restocking fee on all returns unless defective or "not as described" INSURANCE: International shipments to countries that do not allow insurance, buyer assumes FULL RESPONSIBILITY for the safe shipment of their packages. Sound Ideas cannot provide refunds or compensation for packages shipped without shipping insurance. All shipping quotes for packages shipped includes insurance. CONTACT: We stock over 50,000 vacuum tubes. Contact us if you have any special vacuum tube needs. Sound Ideas, 3215 NW 13th Street, Gainesville, FL 32609. (9 am-6pm Monday-Friday, 10 am-5pm Saturday, EST). Since 1977. We carry over 50 new brands of electronics, please stop by the store when you are in Florida. PRESS HERE TO SEE MY OTHER AUCTIONS Matt - Internet Sales Mon-Fri 9am-6pm Sat 10am-5pm Sound Ideas - Gainesville, Florida
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