How important are matched triodes in a 12ax7?
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- jcr1234
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How important are matched triodes in a 12ax7?
One of the 12ax7's I have is an Eico branded Mullard where the triodes measure 900 and 1150 on my Hickok 533a. Are these numbers kind of low for a 12ax7 and indicating that it is near the end of its life? Also, how close do the triodes need to be?
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I think some of the audiophiles go trippy on this one.StarGeezers wrote:First time I ever heard that brought up .. never a concern before ...
I don't have a selection of hi-zut tubes, but I was impressed when I beheld an old telefunken 12ax7 swapped into the PI of a Trainwreck Rocket. The amp went from ho-hum to desireable.
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For the most accurate reproduction you would use close tolerance parts and matched pairs in differential circuits to cancel out as much of the even harmonic distortion as possible. In our case we like distortion, in fact many like the phase inverter to be a little unbalanced to get some second harmonics introduced in the signal. Strangely enough we like distortion. Power tubes benefit from being matched to reduce the unbalanced dc current through the output transformer.
I have a couple of matched small signal tubes and other than them being NOS and should sound sweet it is not the balanced nature that concerns me. More that they are a quality tube. Got them free though, would not have paid any extra for them.
I have a couple of matched small signal tubes and other than them being NOS and should sound sweet it is not the balanced nature that concerns me. More that they are a quality tube. Got them free though, would not have paid any extra for them.
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