Dynaco ST-70 With Highly Desirable Welborne Labs Mods! This amplifier has been fully tested and works great! All tubes tested strong! All matching GE power tubes! Bias was calibrated on both channels! If you have any questions please feel free to ask!
It was rated at 40 watts RMS (20 watts in triode), with two (2) EL34 output tubes. This listing includes one. Vintage Marantz Model 2 Tube Mono Amplifier as shown. The chassis shows signs of corrosion on the top plate with some of the original silk-screening being affected; but most of the print is still present. The tube cover is included; but is missing the grommets to hold it in place. Therefore the cover is loose and not properly affixed to the amp. This particular amplifier is in tested working order; but comes with no guarantees. It should be completely checked out by an experienced (tube) technician before being placed into normal use. All of the tubes shown in photos are included; but none are branded or screened. One 6AU4-GTA has some loose particles inside; and one EL34 is slightly crooked. Please review all attached photos; and be sure to ask any questions. The amplifier will be Very Securely Double Box Packed with High Quality Packing Materials for Safe Transit and No Worries for a Safe Arrival. Power output: 40 watts into 8? (mono). Frequency response: 20Hz to 20kHz. Total harmonic distortion: 0.1%. Input sensitivity: 0.7V. Signal to noise ratio: 90dB. Speaker load impedance: 4? To 16? Valve complement: 1 x 12AX7, 1 x 6CG7, 2 x EL34, 2 x 6AU4GTA. Dimensions: 15 x 9.5 x 6.5 inches. If you are in one of these locations – please message for rates.
Vintage 2A3 Electronic Tube Two – Vacuum Tube Dual Triode Audio Amplifier Radio. The operation has been checked before the sale! It is a used item and has some scratches and stains. Please check the pictures! Please check the pictures. Customer service and satisfaction are very important to us. Return is allowed when the condition does not match with description. Please keep in your mind that we take pictures of all the item’s details to avoid any problem. International Buyers – Please Note. Thank you for your understanding.
This tube (7062/ E180CC) is virtually the same as a 5965 in regard to electrical specifications. Like the 5965, it has slightly lower gain than the 12AT7, and has the added advantage of a 10,000 hour heater life to make it another audiophile “secret” tube. These are superb tubes. This tube is about a half-inch taller than the standard 12AT7, so chassis space is an important consideration. Amperex Made in Holland 7062. ULTRA RARE BUGLE BOY LOGO. TEST RESULTS IN PHOTOS ON BOXES. Tv7 tested NOS TUBES. 90 % of our tubes are Tv7 tested some can’t be tested using the tv7. We have a variety of testers available. All our tubes have been tested for. GAS SHORTS TRANSCONDUCTANCE & EMISSIONS. Please see my notes on noise tests below. Test Results are available upon request. We have a few different testers available to ensure the quality of the tube (as some tubes can not be tested on the tv7). Tubes tested on tv7u the Military standards were tubes needed to meet 60% (minimum value). 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. Thousands of tubes to be listed within the coming weeks! 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. NOISE TESTING a little information and guide. 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. Loose elements or other defects will not be found. This is a very marginal test, only for. 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). There is nothing wrong with performing that noise test. However, 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 is probably NOT testing them in any meaningful way for you. True “noise testing” (other than using the tube in the exact equipment you plan to use it.) requires a highly sensitive mechanical-based or vibration-based test apparatus, and such devices were ONLY created and used by professional engineering and testing labs run by very large entities back in the old days- such as the US military, Westinghouse labs, etc. Furthermore, “Noise” and “Microphonics” are often buzzwords for other issues. 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. So if you find yourself rejecting more than one or two tubes because of “noise”, then you probably have an aggressive circuit design or other design issues (such as transformer placement, shielding, etc).
