This tube should win an award for best and worst in class. The first one I tried squealed in the combo amp and produced a ringing sound in the half-stack. (Remember these were not from the pre-screened tubes that thetubestore.com sells.) The second one I tried was fantastic. There were no microphonics problems with this second tube. The scores for microphonics (2 and 4) are for each individual tube that was tested. A few phone calls to another tech confirmed my suspicion: there is a high failure rate when initially screening these tubes for microphonics. The ones that do pass testing are wonderful; they are very musical sounding with lots of gain and a very low noise floor. When playing the guitar you could really get the benefit of their dynamic range. They can reproduce soft passages accentuated with a sharp punch and you don't have to go near the volume controls. I'm keeping the test tube for some long term testing. These would be great tubes for home audio applications. Due to the microphonics problem, I'm unsure as to their roadworthiness. At home or in the studio, they will deliver great results. The only caveats are; make sure they are carefully screened and don't think about using them in high gain combo's unless they are tested in a similar amp first.
Information from thestoretube.com
2/19/08
Ei 12AX7 Review.
Tesla / JJ 12AX7 / ECC83-S Review.
This tube sports a different plate design than found in most 12AX7's. When you look at them you can't help but think that they must be rugged and good for the musician on the road. The compact plate structure does nothing to dampen their sound or dynamic response. I find them to be well balanced. While not as harmonically rich as others I tested, they do provide high gain without the usual noise and microphonic problems you would expect. This is great sound for your dollar. If you're using a combo amp and find the Philips a little rich sounding, the JJ ECC83 may be your solution.
Information from thestoretube.com
JAN-Philips 5751 Review.
While not really a 12AX7, it shares the same pin-out arrangement and is designed for less gain in favor of lower noise and microphonics. It worked well in both test amps and can be used to advantage if your amp has too much grind. One of these should calm things down a bit. The 5751 is an affordable alternative to the 12AY7 used in original Fender tweed amps and can be subbed for a 12AT7 like a reverb driver tube. In this application, you will get good gain with a warmer sound than the 12AT7. The even balancing makes them a nice phase inverter and allows you push the front end of the amp a little harder.
Information from thestoretube.com
JAN-Philips 12AX7WA Review.
If you really want NOS (New Old Stock) tubes, this is one of the best buys out there. The Philips tube is well built and should be long lasting. The tubes I tested had lots of gain while still maintaining very good noise levels and good tolerance for microphonics. The tone was solid in the midrange with very wide dynamic response. If you're not careful with your setup, you can get these tubes to be boomy in the bottom end and shrill in the high end. I found that they were great with the tone controls set flat. Great in both combo amps and monster stacks.
Information from thestoretube.com
Sovtek 5751 Review.
The Sovtek 5751 is an affordable alternative to the 12AY7 used in original Fender tweed amps and can be subbed for a 12AT7 reverb driver tube. In this application, you will get good gain with a warmer sound than the 12AT7. The even balancing makes them a nice phase inverter and allows you push the front end of the amp a little harder. If you wish to use a 5751 in a 12AX7 position to reduce gain we recommend you use the JAN-Philips 5751 tube.
Information from thestoretube.com
Sovtek 12AX7-LPS Review.
This is an entirely new design from Sovtek and a great step up in sound quality. They have very large ribbed plates and great sound reproduction. I found them very smooth and well balanced in terms of bass, mids and treble response. The large plates make them more prone to microphonics and in combo amps, so they can be a problem if you like to run things wide open. It is still the best thing Sovtek has produced in a 12AX7, with very good gain and low noise. I would advise against using them in compact high-powered combo amps where they will be subjected to lots of vibration. One other note about the construction of these tubes is they have filaments that are almost completely encased in the plate structure. They often don't "light up" when working properly. This is not a problem, it's normal for the LPS.
Information from thestoretube.com
Sovtek 12AX7-WA, 12AX7-WB Review.
I've grouped these two together because they have essentially the same sound. The only noticeable difference between the two was a bit more gain from the WB model. These tubes are rugged little brutes, and that's probably why they are OEM components for many major amp makers. Both tubes could be whacked with a stick at full volume and not show much in the way of microphonics - but DON'T DO THIS AT HOME, as it is often a destructive test for tubes. They don't have the best sound in this type, being prone to the occasional pop or tick. The sound quality lacked any real character but was acceptable. If the budget is tight, their affordability will be attractive. Also, keep in mind that many amp designers design the equipment to sound best with the tubes they will use in production. I have a friend that claims his amp only sounds right using Chinese pre-amp tubes, but your mileage may vary on this issue. If you like the Sovteks then go for it, particularly if you will use them in high gain applications with lots of effects.
Information from thestoretube.com
Electro-Harmonix 12AX7 Review.
These are not relabelled Sovtek 12AX7-LPS tubes. There is a marked difference in construction and performance. The 12AX7 EH has a nice balanced sound, fairly low noise floor and excellent performance in terms of microphonics. The lack of microphonics may be in part from the return of the shorter plate structure or materials. I've had some samples that were tried in various amp stages. Pre-amps, tone stacks and phase inverters, a winner in every location, although I like to use a 12AT7 for reverb circuit drivers due to their lower gain rating (just a personal preference of mine). I have used the EH to successfully tame amps that defied all other attempts to kill microphonics and unwanted feedback. This tube is a winner, buy 'em and try 'em, they may be just the piece you've been looking for.
Information from thestoretube.com
Mullard 12AX7 / ECC83 Reissue Review.
This is a nice tube but in my opinion better suited to home audio than guitar amps. The tubes have well balanced triode pairs and a very even flat response. Compared to a Tung Sol it sounds a bit flat, but so does a NOS Mullard. Microphonics are not an issue despite the larger that average plate structure. The transconductance on my sample was the same as two NOS samples I measured. Not really high gain at all, but a real good noise floor and a nice smooth tone that doesn’t encourage ear fatigue the way some preamps can be. The Tung-Sol 12AX7 is my favorite preamp for guitars because it accentuates highs and lows. The Mullard adds virtually no tone coloring and is smoother sounding to my ear that a JJ ECC83S. For hi-fi gear the Mullard will likely be a winner but there are better choices for guitar amps for less money.
Informaition from thestoretube.com
Tung-Sol 12AX7 Reviews
There are only so many ways to describe tube tone and most have become clich้'s. The Tung-Sol 12AX7 has the gain and drive of a Chinese 12AX7 and the pure tone of a Mullard or Brimar from the U.K. I've had two people come to me recently with amps they thought were in need of complete overhauls. In both cases, careful examination revealed no serious problems and all the tubes "tested" as good. At the end of the day, I replaced the NOS Mullard and RCA pre-amps (one in each amp) with a reissue Tung-Sol 12AX7. In both cases the owners were very impressed and thought that their amps had been restored to full health. Believe it or Not.
Information from thetubestore.com
12AX7 Tube Type Review
Review Notes Guitar Amp Tube Reviews written by John Templeton.
The tubes used in this review were selected at random from thetubestore.com's inventory of untested tubes. For each tube used in the test, two were taken since there was no pre-screening involved. The aim was to get a sample that would be practical to work with but allow for variations in the tubes or prevent picking the only dud in a lot.The test amplifiers used were very different. One was a 100-watt Trace Elliot Speed King with 4 x 12 cabinet, and the other was a Fender Blues Junior combo amp. This allows the high power, high gain crowd and the more conservative players to get the fairest evaluation possible. Some tubes were clearly better suited in one application or usable in both. All tubes were used at the input amplifier stage of the amp since this seems to be where most people develop their perceptions of how good a pre-amp tube is.
What Makes A Good Tube? The musical detail or ability to reproduce the sound of the instrument is a key factor in assessing a tube for guitar amplifiers. There is no perfect tube available. Each one has strengths, weaknesses and certain factors that contribute to its overall ratings. Usually a compromise is arrived at in the search for premium tone. All tubes will exhibit some degree of microphonics. Microphonics do not mean that a tube is unusable. You just have to screen them a little closer and determine where they are best suited for use. Input pre-amps are the most sensitive areas of the amplifier. When used in this application most tubes will generate some noise if you tap on them with a pencil during operation. Keep in mind that doing so can actually damage the tube and make it more microphonic or cause it to fail if you hit it real hard. Although they are screened prior to shipment a tube is an electromechanical device and can be damaged during shipment. A microphonic tube will ring, howl or produce general feedback problems. It will be more noticeable at louder volumes or when used in close proximity to a speaker, typically in combo amps. If the tube has good tone at lower volumes and is free from unwanted noise, you use it in a less sensitive part of the circuit, such as tone recovery or phase inverter applications.
Noise is more of a problem than microphonics. A noisy tube will make random popping noises, crackle occasionally or just hum. All tubes have a certain noise floor; this is the inherent background noise that the tube makes in operation. Typically, you will notice this as a soft hiss or "white noise". Tubes designed for high gain can exhibit more background noise. Other components can cause noise problems that may be blamed on a bad tube. Plate resistors are notorious for causing hiss and crackling as they age and begin to fail. A new tube may better amplify these defects, so try substituting another new tube to be sure of the source of the noise.
Information from thetubestore.com
6P1P
The 6P1P (Russian: 6П1П) is a Soviet-made miniature 9-pin beam tetrode vacuum tu
be with ratings similar to the 6AQ5, EL90 and the 6V6. Because of a different pinout (a 9-pin base versus 7-pin base) than an 6AQ5/EL90, it cannot be used as a plug-in replacement for these types, however, it will work in the same circuit with component values unchanged. Its maximum plate/screen voltage and dissipation ratings are actually slightly higher than a 6AQ5. A ruggedized/extended ratings version of the tube is designated 6P1P-EV (Russian: 6П1П-ЕВ) roughly equivalent to the 6AQ5W. A Chinese-manufactured version of the tube also exists, labeled 6P1.
The type was commonly used in Soviet-built vacuum tube radios and TV sets as an output audio amplifier, until it was replaced by the higher-performance 6P14P (EL84) tube.
The tube is no longer believed to be in production.
Also see 6AQ5, 6V6 and Russian tube designations.
6N3P
The 6N3P (Russian: 6Н3П) is a Russian-made direct equivalent of the 2C51 vacuum tube. It is slightly larger in size than the American tube.
6N3P was widely used for FM band radio input unit stages (nearly all 1960s Soviet radios with FM band all employed the same input unit on a separate subchassis). Currently, it has some use in DIY preamps. A ruggedized/industrial version of the tube is designated 6N3P-EV (Russian: 6Н3П-ЕВ
From Wikipedia, the free encyclopedia
6N2P
The 6N2P, (Russian: 6Н2П) also sometimes spelled in English "6H2Pi" is a miniature 9-pin dual triode vacuum tube manufactured in USSR, Russia and China with characteristics similar to the RCA 12AX7. The most significant difference between the two is that 6N2P has its two filament elements connected in parallel, unlike the series filament connection of the 12AX7, and it is thus only possible to operate it from a 6.3 volt, 300 mA filament supply (whereas a 12AX7 may be operated from either 6.3 or 12.6 volts.) The 6N2P also has slightly lower gain than a 12AX7.
A Chinese version of 6N2P exists, labeled in Latin lettering (instead of Cyrillic) 6N2.
In the 1990s a (now extinct) line of "Red Bear" guitar amplifiers was being produced in Russia by Novik Ltd. and distributed in the United States by Gibson Guitar Corporation. These amplifiers used 6N2P tubes instead of the much more common 12AX7, prompting user modifications of the amplifier to 12AX7, because the original Russian 6N2P was scarcely available outside of Russia.
On the photo, from left to right - 6N2P produced in USSR in 1967, 1974, 6N2 produced in China and Soviet 6N2P-EV (left), produced in 1980.
6N1P
ouble triode vacuum tube intended for use as a line audio amplifier and cathode driver.Basic data: Uf = 6.3V, If = 600 mA uM = 35 Ia = 7.5 mA S = 4.35 mA/V Pa = 2.2 W
The 6N1P has similar ratings to the 6DJ8 and in the past was sometimes rebranded as such, however, because of the differences between the two types (such as twice as high filament current of an 6N1P and three times smaller S value) it's not suitable as a direct replacement in 6DJ8 applications and vice versa.
A ruggedized/extended ratings version of the tube is designated 6N1P-EV (Russian: 6Н1П-ЕВ)
It has currently found a use as a driver tube in hi-fi tube amplifiers (such as Audio Research models VS55 and VS110) because of its excellent low distortion and low noise characteristics. The tube is being manufactured by "Voshod" plant in Kaluga, Russia (see [1]) and is being distributed in the West under the Sovtek and Svetlana brand names.
