RCA NATIONAL UNION KEN-RAD Sylvania JAN 1625 VT-136 Vacuum TUBES

Description: One per purchase Various brands Tested! All tested good and above the military minimum standard! Tests above the tv7 minimum standards The 1625 is electrically identical to the 807, except for the heater requirements and base cap. At 12.6 Volts the 1625 would have been designed for mobile equipment. The base looks like UX7 but is slightly different and is designated as U7B (medium). The parameters given are for single ended use. When used in a class AB1 push pull pair with 600 Volts on the anode an output power of 65 Watts was normal. These valves were much used in medium power amateur radio transmitters for high level modulation. In this use the output transformer, called a modulation transformer, would be impedance matched to the anode circuit of the RF power valve. The audio power would increase or decrease the amplitude of the RF envelope. The 807 itself was a workhorse of the HF bands. As a transmitter power amplifier (shown in the lower table) operating in class C producing 40 Watts of RF, it would need a pair of in push pull to generate the 20 Watts of audio required to fully modulate the valve. Other modulation systems operating on the screen grid would require much less audio drive but with less RF output. Tv7 tested TUBES Test Results are available upon request if not photographed in the listing or already stated. 90 % of our tubes are Tv7 tested The tv7 tester has been around a long time and is a trusted tester . Military standards were tubes needed to meet 60% (minimum value) There isn't a specific percentage or data set anywhere that universally designates a vacuum tube as "new old stock" when using a tester nor for what test result is given. The term "new old stock" generally refers to tubes that are unused and have been stored for a long time, often in their original packaging. When testing vacuum tubes, testers typically measure various parameters like emission, transconductance, and leakage. Tubes that test within certain specifications may be considered good or usable, but whether they are specifically labeled as "new old stock" depends more on their history and how they were acquired than on the test results alone. NOS is subject to interpretation and there is no specific definition for it either. There is suggestions. In fact the only definition courtesy of the great World Wide Web and its resources bring up the grand definition of New Old Stock" (NOS) is a term commonly used in various industries, including electronics like vacuum tubes. It refers to items that are old but have never been used. In the context of vacuum tubes, NOS tubes are tubes that were manufactured in the past but were never sold or used. These tubes are considered new because they have never been used, but they are old because they were manufactured some time ago. All our tubes have been tested for GAS SHORTS TRANSCONDUCTANCE & EMISSIONS If they are listed they have none of the aforementioned. Please see my notes on noise tests below ***We have a few different testers available to ensure the quality of the tube***** (as some tubes can not be tested on the tv7) Tv7 testing is tedious and I spend 12-13 hours a day testing tubes and double testing tubes - if you notice a mistake(like a picture doesn’t match the title) please be gracious and let me know. UNLESS PHOTOGRAPHED WITH THE ORIGINAL BOX- tube will come in repackaged white boxes- 50-90 year old cardboard packaging doesn’t hold together well. ***we have over the last 20 years amassed a huge collection of vintage amps/ parts / tubes and have decided to downsize that collection Every tube has been marked for tracking and security purposes - these marks wipe off easily and without the mark no return will be accepted - Sound quality is tremendously SUBJECTIVE. Please let us know what your intended application is prior to purchase if you have a specific sound in mind and/or just don’t know what you want. NOISE TEST. This is a very marginal test, only for special checking. This test needs sound amplification; hearing listening to noise with headphones would indicate a real disaster inside a tube (THE shorts test WOULD already BE evidence OF THIS) some testers do have noise test jacks that connect to either headphones or to the antenna/ground terminals of an AM radio. There is nothing wrong with performing that noise test. *****this test is not going to tell you whether the tube will be silent in your SET (single ended triode) amp or in anything else. *****Ultimately, the best way of testing a tube for microphonics is in an actual chassis or amplifier similar to one in which it is intended to be used.” Since amps have a wide variety of circuit designs and tube placement, this test is most effective in YOUR AMP or one that is almost identical. Hence, most people advertising tubes as tested for Noise or Microphonics are probably NOT testing them in any meaningful way for you. “Noise” and “Microphonics” are often buzzwords for other issues. (Shorts/ leaks) -there is a small percentage of tubes that have a problem with noise but far less than most people think. *****In properly designed circuits objectionable “tube noise” is seldom found. ******* In other words, it is a rare tube that will be noisy when used in most circuits. Always check the data sheet of the tube you plan to use. Tube testers and noise testing- Tube testers do not test for these problems in the manner in which you think, except to the extent that a tube tester with sensitive leakage detection will find far more “noisy” tubes than a tube tester with only “fair” leakage sensitivity, to the extent that the noise is due to this problem. Listening through headphones to tube on a tester is half as good as putting in amp and listening for noise. 1. RETURNS: I want you completely satisfied with your purchase from me. I will bend over backwards to make sure that you are a happy customer, prior to and after purchase. PLEASE message me BEFORE you open a return. 2. PLEASE NOTE: Tube silkscreen (lettering on the tubes) is VERY fragile. It can be wiped off and destroyed VERY easily.RETURNS ARE NOT ACCEPTED BECAUSE YOUR TESTER SAYS SOMETHING DIFFERENT THAN MINE. If you don?t like the sound of a tube, so long as it is still in the same condition as arrived message me and I?ll work with you

Price: 25.2 USD

Location: Columbia, Tennessee

End Time: 2024-09-21T19:15:26.000Z

Shipping Cost: N/A USD