Да, вот еще кое-что для размышления
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Selecting tubes for different sound
Don't be misleaded by the internet tube doctors who claim they have all kind of different sounding tubes for you. They classify the tubes by self-made systems, and start to believe in this themself. Some have very detailed tables and others claim the select them by hearing the "sound" for you. They offer you more tranparent mids, and deeper bass, and a brilliant highs, and all kind of great things we all need. Do these people really give you what you need? Probably not.
The truth about tube selecting for "sound" is very simple:
* All good tubes have exactly the SAME amplification factor.
* Differences are in transconductance and plate current. However.... tubes with above avarage plate current have above avarage transconductance too. So you can select only for tubes that have above avarage values or below avarage values. So.... do all people need "above average" tubes? Well.... on Ebay it seems this is so. But.... the real answer is: no! Suppose a tube has an avarage value of 60mA by the datasheet. If all people would be more satisfied with 70 or 80mA tubes, then the tube design engineers (who are generally not stupid) would have designed the tubes with 80mA in the first place. If the avarage value is 60mA, then that's not just an "avarage" tube, that's a very good tube. A 60mA tube is better than a 80mA tube, because 60mA is the value the tube is made for, and 80mA is a deviation caused by something tolerances in production. For the same reason an 80mA tube is no BAD tube, and 40mA tube is alo no bad tube for this reason.
What sound differences will you get from tubes with higher or lower current than average?
-> Tubes with higher current (as found on the tube tester) will give a fraction more loudness, have some more impulsiveness, and a bit clearer sound. This is best for music with great differences in loudness, and many instruments playing at the same time, like with classical music. Also this gives best results for instruments that by nature have great loudness variations, like grand piano or percussions.
-> Tubes with lower current than average will have a more silky sound, like what some people call "tube" sound. This is nice for softer kind of music, like Jazz or vocals, cello or saxophone. Also when have high efficiency speakers, these tubes may be more what you like.
