Tube Rolling - No Change in Sound

There are four possible explanations.

1. The circuit design of your Wyetech Opal may not be particularly sensitive to variations in tube parameters.

2. While the internal tube design characteristics of the same tube from different manufacturers can vary, it doesn't mean they always do. Your Ken Rad and Philips may have been closer in characteristics than some other combination.

3. There was a difference but it is masked by other aspects of your system.

4. There was a difference but you may not be particularly sensitive to it. Different people listen for different things in music and the change resulting from this tube switch may simply fall in an area that isn't very high on your list of sonic priorities.

It could also be a combination of more than one factor noted above. There are also subcategories (you needed longer burn-in or more listening time/different music in order to hear subtleties, etc.) but you get the idea.

The primary point should be you have tried it for yourself. Even though someone else may have different results from the same experiment is ultimately irrelevant for your situation.

Don't know who told you KenRad VT-231s would add anything to your sound. They are a very transparent tube, adding/taking nothing from the signal(as are the TungSol Round plates, Sylvania VT-231/6SN7GTs and 6sn7Ws). Raytheon, National Union, and RCA VT-231s will all give you a bit more of the sound you're looking for, to various degrees. They are all a little euphonic(warmer) than the others. I've got three matched NOS pairs of the KenRads, for when I can't find(or afford) the TungSols and Sylvania 6SN7Ws that I love so dearly(for the above mentioned reasons).

Msstl's number one response is probably right on...I would have contacted the MFG and asked what tubes in the unit respond most to rolling...just changing tubes out doesn't always change the sound...the KRads are great BTW

Well, trounce me if you want, but I still STRONGLY maintain that the sonic signature of any system is at least 85% determined by the amp and speakers. As for preamps, I think one thing you WILL get out of tube rolling is (maybe) a quieter/lower noise floor (depending on the tube you select.) This is certainly true for tubed phono preamps. But the amp is where I'd look to effect tonal changes through tube-rolling.

Of course if you have a solid state amp, you're going to get the detail and slam for which ss is well known. But if you don't like the sonics, you'll have to roll the whole amp!
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