CDSoundMaster Audio Software

Vacuum Tube Comparisons

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Library Creator: Michael Angel, www.CDSoundmaster.com

Tube Comparisons - 12au7 - Using The Source + Plus TM

This group of audio samples has been created to display the differences and strengths of several highly sought-after tubes. These comparison files have all been recorded through an original hardware design we created specifically to perform the ideal sound of 12-series dual triode tubes without anything else in the path, it was called the Source Plus TM. This is the device usd to provide the natural sound of the vacuum tubes included in the Vintage Tube Collection software.

Each mp3 below begins with a clean setting, followed by increasingly more 'driven' signal levels. Each setting beyond 'clean' has been tuned to show off the best characteristics of each tube. Therefore, some examples may have 2 example settings, where others may have 4.

My personal experience has been that many of these recordings present exactly why people choose certain tubes for specific qualities. It also showed me how wide a spectrum of character each individual tube possesses, and no single tube beat all of the others hands down in all categories. For instance, I found that the long and short plate Mullards matched the expectations of the 'sound of a Mullard' in every respect, where the short plate was more tight and focussed while still forward and warm, perhaps slightly easier to make sound overall balanced and 'big', where the long plate was smooth, easier to maintain balance of extreme lows with complex material, and had more of a range of lightly overdriven harmonics before breaking up, while once again exhibiting all of the warm focussed sound that is desired.

I believe that the JJ/Tesla is an excellent, usable, and very impressive newly manufactured tube. It reproduces complex material very well and can be driven into many characteristic tones and overtones with a great range of flexibility. I would say that some of the dimensions of sound that set it apart from the more expensive 'classics' include being more punchy, as the JJ/Tesla's accentuate transients in clean modes. As it is overdriven, it remains a little brighter and a bit more even in how it overdrives the full range of frequencies. This is an excellent characteristic for individual instrument processing and makes it a powerhouse for use in recording. We chose this tube for the Source Plus TM for these reasons. Having said that, I strongly encourage everyone to experiment with tubes and discover their personal favorites, and more specifically their favorites for different material. For those who are simply looking to find the right tubes for audio, the recording examples on this page give you a good feel for how tubes sound under different conditions and should serve as a good compass for the sound you are after.

The 1958 Radiotechnique is a fantastic sounding tube that exhibits many of the pleasant characteristics of the long plate Mullard, but has its own personality as well. It remains round and smooth with a generous amount of overdriven signal.

The 1964 Brimar 13D5 long plate is a surprising and unique tube. It has a very lively sound, and for those who prefer this Brimar over the slightly more musical, more subtle 'personality' tubes like Mullards, they will find this tube is easy to get a very wide range of sounds when using it in recording equipment. While they are available at reasonable prices, it is a great alternative if you have audiophile equipment that is finicky or you just haven't found the right tube.

The 1964 Amperex Bugle Boy short plate is an exceptionally well-balanced tube. It can reproduce complex material almost identically over and over again, but is not short of personality either. If I had to stick with only one tube, this would definitely be a candidate. If I were using tubes only in the context of an individual instrument, there would probably be stronger choices to get the right flavor. For example, for a Vox amp, I may want to go all the way in the 'warm yet defined' direction of a Mullard, as with a Leslie running a Hammond where smooth warm overdriven break-up defines the instrument's personality. For audiophile preamps and the sort, the Amperex Bugly Boy may be the perfect choice.