TUBE HUNTER VACUUM TUBE GEMS. THESE ARE THE SPECIFICS OF THE TUBE/TUBES/PARTS FOR SALE. THESE ARE THE TUBE/TUBES/PARTS FOR SALE. SILK SCREEN CONDITION %. CURVE TRACER ma: NORMAL = 30ma TUBE #1. 34ma AND 31ma AT 200PV AND 0G. CURVE TRACER ma: NORMAL = 30ma TUBE #2. 31ma AND 33ma AT 200PV AND 0G. TRANCONDUCTANCE: NORMAL = 2200. PERCENTAGE OF BOGEY: TUBE 1. PERCENTAGE OF BOGEY: TUBE 2. BF = SEPT 1966. These are very special RCA 12AU7 twin triodes. This is a nearly perfect example of one pair of the best sounding 12AU7′s tubes ever made. You will not be disappointed in this tube. Some say the side getter contributes to the low microphonics of this tube. Wonderfully balanced airy highs, mid range warmth, and accurate bass……… This tube is an incredible bargain among NOS tubes. Stock up now, this tube is vanishing from the market just like the Telefunken smoothplates! On my tester a B&K 747 tester. Below 55 = BAD. 65 -100 = GOOD. NOTES ON THE BOXES. LISTING WILL GENERALLY HAVE INFORMATION ABOUT ANY BOXES ASSOCIATED WITH THE TUBES FOR SALE. THESE ARE THE OPTIONS. ORIGINAL BOXES IN VARYING CONDITION. THESE BOXES WILL BE THE ORIGINAL BOXES THE TUBES CAME IN AND WILL SHOW AGING IN VARYING DEGREES. THESE TUBES ARE ASSUMED TO BE NEW AND WILL TEST AS NOS. NO BOXES PROVIDED NONE AVAILABLE USUALLY USED AND SHOULD BE ASSUMED TO BE USED UNLESS OTHERWISE STATED. THESE TUBES SHOULD BE ASSUMED TO BE USED UNLESS OTHERWISE STATED. THESE ARE BOXES I HAVE MADE WITH GREAT TIME AND EXPENSE TO PROTECT YOUR VACUUM TUBES AND PROVIDE FOR STORAGE AND EASY IDENTIFICATION. TUBES IN THESE BOXES SHOULD BE ASSUMED TO BE USED UNLESS OTHERWISE STATED. SHOULD BE SELF EXPLANATORY. THIS IS DONE ON A NUMBER OF TESTING DEVICES. B&K 747 TUBE TESTER. MERCURY 1000 DYNAMIC MUTUAL CONDUCTANCE TESTER. NOS = 80% TO 135%. GOOD = 65% TO 80%. OR MARGINAL : 55% TO 65%. TESTING RESULTS SHOW HOW THE TUBE IS PERFORMING NOW. TESTING RESULTS DO NOT SHOW HOW OLD A TUBE IS OR HOW MANY HOURS IT HAS BEEN USED. HOWEVER IF A TUBE TEST NOS YOU CAN BE ASSURED IT WILL LAST A LONG TIME AND IS WORKING VERY WELL. I will never sell a tube that is below standard.. I will work with you in good faith if there are any problems, or if you are unsatisfied in any way. All tubes are tested for shorts, continuity, and emissions. I will bend over backwards to make sure that you are a happy customer. Sound quality is tremendously. PLEASE NOTE: Tube silkscreen (lettering on the tubes) is VERY fragile. It can be wiped off and destroyed VERY easily. DO NOT handle the tubes or hold them from the cylinder. ALWAYS hold them from the ENDS. THIS IS VERY IMPORTANT. TESTING: I test all tubes that I sell in one way or another, or I will state “untested”. I have a B&K 747 tube tester. This is a mutual conductance tester. It give a percentage value of gm for the tube under test and checks for shorts and grid emissions. I also use a Tektronix curve tracer for testing triodes. I give a number of evaluations for tubes. One evaluation is a screen shot of the tube with a high voltage applied to the plate. The Curve tracer steps the triode through 10 gate/grid voltages starting with -10 volts and going to 0 volts. The lines show how the tube conducts throughout that range. At 0 volt the tube is at max conduction and is the top line on the display. It is easy at that point to take where that top line intersects the plate voltage, find the milliamp level and compare it to the datasheet. I give those numbers for you in the “Item condition box”. This can then be compared to other tube sellers using inferior test methods such as Hickok. Amplitrex, and other testers. The Tektronix curve tracer gives values within 3% of the actual value. The very best portable testers only can approach 10% accuracy. Please note: The numbers given for gm are what I see on my tester. I DO NOT guarantee that you will see those numbers on your tester. I only guarantee that these tubes will test good, with no shorts, or gas, on a decent calibrated tester. I don’t guarantee or imply anything else. Vintage tube testers almost always, due to age, have VERY LOW HEATER VOLTAGES!!! Every tester I have ever bought is below 6 volts when selecting 6.3 volts. They average 5.8 volts. The voltage NEEDS to be 6.3 and 12.6. You can calibrate a vintage tube tester all you want. If the heater voltage is not right, you will NEVER get the right gm value. I have customers complain that their tubes are not the same as what I see on my tester. They say they have a calibrated tube tester. I have 40 tube testers. On all of them I have an outside regulated DC power supply that feeds the tube tester the correct heater voltage. I don’t check each and every tube for noise or tone. This is SUBJECTIVE and it is too time consuming. Please wait for us to invoice you for the correct amount. This is an honesty issue. We are honest with everyone to the best of our ability to do so. We want you to trust that what we say is true. There cannot be that trust, if we make false statements knowingly to anyone. And all the Angels sang because the heavenly music was playing and it was turned all the way up. Listing and template services provided by inkFrog. This item is in the category “Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Parts & Accessories\Vintage Tubes & Tube Sockets”. The seller is “mercedesman6572″ and is located in this country: US. This item can be shipped worldwide.
- AUDIOPHILE LOW NOISE: PHONO LOW NOISE PREAMP
- Brand: RCA
- Country/Region of Manufacture: United States
- FENDER GIBSON AMPEX: BRAVO AUDIO HEADPHONE
- GUITAR AMPLIFIER: TUBE AMPLIFIER
- LOW MICROPHONICS TESTED: HAND SCREENED FOR AUDIO
- Model: RCA 12AU7 CLEARTOP
- ORGAN TUBES: BOTTLEHEAD CRACK
- Type: Vacuum Tube
- VINTAGE TUBE: WELL BALANCED VINTAGE
