Some of these tubes were 'OEM, - Original Equipment Manufactured' for other companies.This means that, for example, producers like RCA or Mullard manufactured tubes for other companies, and would put a different company logo on the tube.The main sonic differences between Long Plates and Short Plates can be summed up in three words: '3-D,' 'Lively,' and 'Open'.By and large, Long Plates have a bigger sound in guitar and audio amps than short plates (with exceptions.) However, Long Plates can sometimes be vulnerable to noise and microphonics.These types of tubes are very popular among Fender users, who are looking for a classic 1950s-1960s rock and blues sound.The exception to this rule are the black plate tubes produced by RCA, Sylvania, Raytheon, and Ken-Rad.
USA 12AX7/ECC83: These tubes include those produced by RCA, GE, Sylvania, Tung-Sol, Raytheon, Ken-Rad and a few others.European ECC83s are generally sought after for their warm sound (with exceptions -- Telefunken, for example).These tubes emphasize even order harmonics, so you get a warmer clean sound, and a very harmonic overdrive sound in a guitar amp which is very pleasing to the ears. If you're anything like me, then you're passionate about vintage and NOS 12AX7 Audio and Guitar Tubes, so I am writing this guide to give my customers information about these fantastic tubes... I will also briefly discuss the real meaning of a ' NOS' tube, tube faking, and overcharging for tubes by some dealers.how, when and where they were made, how to decipher tube codes, and most importantly, how they sound. European ECC83/12AX7 : ECC83 is the European designation for the 12AX7 tube -- (it is the same exact tube).Short plate 12ax7 tubes were first produced in the early 1960's by the likes of RCA, GE and so on, and then picked up by the European producers such as Philips, Mullard and Amperex.