The vacuum tubes used seem to make such a big difference in the sound quality of preamplifiers that we are considering offering a spare set of tubes with our tube and hybrid preamplifiers. We would supply the units with Electro Harmonix 12AT7A tubes installed (which we consider to provide the clearest, most transparent, and true to life sound) and supply a spare set of Amperex 12AT7A tubes at no extra charge (which have a much more "tube like" character).
Here is what one recent customer said about the Amperex tubes:
"Hello again, Frank.
We installed the NOS Amperex 12AT7s that you mailed to me in our T6 preamp yesterday, and I had promised to let you know how they perform.
They have made a significant improvement to the sonic character of the T6!! The Amperex are even cleaner than the NOS Brimar tubes that I had purchased a few weeks ago via the web.To say that I am grateful for your outstanding service is an understatement. THANK YOU. The unit is now much more relaxed, yet still detailed, in sound quality. The harshness and hardness of the EI tubes is gone. Now I can truly hear the sonic signature of your circuits."
I suspect that some audiophiles have brighter sounding speakers/amplifiers/rooms than they realize and their systems cannot tolerate the extended range and clarity of the Electro Harmonix tubes and their systems don't have the overall resolving power to do complete justice of the Transcendence preamps as is.
In contrast, here is another recent client's evaluation of a T7 EC preamp supplied with our standard Electro Harmonix 12A7TA tubes:
"The Transcendence Seven made a dramatic difference in the sound of my system. It does a better job of reproducing the rapid dynamic contrasts (e.g. the attack of a drum or piano or the rapid starting and stopping that create the "texture" of the sound of a bowed string) that make performances of unamplified music sound unmistakably "live."
This resolving ability has a number of effects. First, it dramatically reduces harshness and sourness that (based on listening to a wide variety of expensive, highly regarded equipment), I always assumed were on (some of) my recordings. Second, it allows me to hear the changes in tonality and volume that are essential to musical communication much more clearly. Third, it portrays each instrument noticably more realistically. Fourth, it makes it much easier to distinguish similar sounding instruments (say, two violins) from one another. Fifth, it allows individual instruments and voices to be heard (and followed) much more easily, even in complex, densely-orchestrated passages. Finally, it captures more of each instrument's "three-dimensional" quality and places each performer more securely in his or her place on the stage.
While these characteristics may sound subtle, the net effect is not. The Transcendence Seven makes music more relaxing and enjoyable while making it more dramatic and exciting.
It includes a superb headphone amplifier, which allows headphone listeners to appreciate all of its virtues.
I've never heard a better preamp, regaradless of price."
Now this is the way we hear it and what we hope our clients hear too, and to our ears, using alternate tubes (Amperex, Mullard, etc.) all loose too much of the resolving power that we worked so hard to get in the first place. Perhaps most high priced speakers are nowhere as resolving as the Biro L/1s we make.
I am kind of baffled by this and would appreciate reader comments.
Frank Van Alstine