[avahifi]

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

[brians]

I am looking forward to recieving the T7SL w/ phono (you should receive my order any day).  I have Magnepan 1.6 speakers which may have a bit much energy in the upper midrange, so I may be interested in something a bit more mellow (but I don't know until I hear it).  I have never swapped tubes in anything yet, but would be willing to compare.
I do have an Anthem Amp 2 SE (speciel edition) which comes w/ a Brimar tube on the input section, so I guess Anthem thinks that that is an improvement over the newly made tubes.
I would be willing to try another set to learn about the sound of tubes.  My speakers are quite revealing of any changes I believe.

BTW, what is the break in time on the T7?

Thanks,
Brian S.

[Tyson]

Interesting, because brad b and I got together last weekend to do a "tube shootout" on my system, to see which was the best match.  I did the switching between the stock electroharmonix, some Brimar's, some Mullards, and some Siemen's.

To make a long story short, we ended up with the Siemens as the primary choice.  The mullards were not as full in the mids, and less resolving.  The Brimars were pretty resolving and quite creamy in the mids, but had a bit too much of the classic tube softness.  The ElectroHarmonix tubes did not convey the emotion quite like the Brimars or the Siemens and were not any more resolving than the Siemens.  

I want to also say as an aside, that I agree with everything that the person in Frank's 2nd example said.  Even with the stock tubes, I have never heard a smoother or more dynamic preamp (or amp) that uses solid state output.  Swapping tubes to me is more about taking a great piece of equipment, and "flavoring" it to your own personal taste.  That's the fun of having tube gear.

Below is a pic from the gallery of my speakers, they don't get much more resolving than this. . . (the plants you see in the picture are all outside now, so nothing is obstructing the speakers):

[brad b]

Obviously Tyson has a VERY resolving system, so listening to different tube configurations indeed made a difference, with the Siemens to me conveying a good solid midrange without giving up the detail.  The stock Electroharmonix in comparison felt slightly thin in the midrange, with the top end about the same.  Interestingly the Mullards provided the tightest bass of the bunch, but lacked in the midrange.

I really think each speaker configuration is going to determine tube selection, so Frank as hard as it may seem, some of us like a little different tube than what you provide.  As Tyson said, stock out of the box, the unit is very good.  What I am referring to is simple personal taste.

Frank, since Tyson and I purchased our amps and preamps not too long ago, what do we have to do to get a couple pair of the Amperex tubes to try.  Maybe they are exactly what the doctor ordered?
Brad

[Tyson]

Actually, the Mullards had the tightest bass simply because I had tuned the bass of the RM40's to them over the previous 2 weeks or so.  Since I've put the Siemens in, I've re-tuned the RM40's to them, and the bass is just as tight as the Mullards.  But neither the siemens nor the mullards do the really deep bass as well as the EH tubes (ie, below 30hz).  Not a huge concern for me since most of my music doesn't reach down that low. . .