Biasing current production tubes

In the past output tubes and preamp tubes were much more consistent than they are today.  One could use the older method to bias output tubes with the scope/crossover method which had one adjust bias until the crossover notch distortion…

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Tube Matching

You cannot convert a GT dynamic number to a static number. The GT number is based on where the tube distorts not just the idle draw. The only way you can do a close version of conversion is to have…

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NOS Tubes – The hype, myth, and reality.

Are NOS tubes any better or different than the new tubes made today? Many folks cannot seem to tell the difference. After a recent batch of new tube testing, where NOS tubes are used as a standard for some areas…

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Reissue versus the original amps

In the above "article", there may be the misconception (or from some of my two forum's comments), that I was saying that the reissue amps can "be" every bit the same as the originals.  This is not the case in…

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Gain and Current in preamp tubes

I ran into numerous amplifier problems. ALL of these could have been avoided if some basic information was known or considered by the amp owner. I have said a lot on this subject, but it is worth repeating, maybe in…

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The 12AX7/7025/ECC83 Tube family

I received a question from one of the folks on a forum in late 2007 who wanted to retube his whole amp. For his objective I felt it was not necessary to replace every tube. He was making some classic…

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Preamp Tubes – most overlooked tubes in your amp

Unlike power/output tubes, which are routinely matched when they are sold (in different ways, some much better than others), preamp tubes are tested at best to:  (a) make sure they work,  (b) they are not microphonic.  In testing, we have…

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Tone Stacks, Response and why amplifiers sound different

Why does a Fender amp sound differently than a Marshall?  Why do some amplifiers sound "louder" than others?  There are many factors, some you might know right off the bat.  Power for one.  Is a 100-watt amplifier twice as loud…

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