Quote:
Originally Posted by Richman1
What is the real deal about this 12AX7 in V4 being balanced. Eurotubes claims that it must be a special hand picked balanced tube for V4. Some people say thats bullcrap and you won't hear any difference if you stick any new 12AX7 in there????
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A 12AX7, being a dual triode, has two gain stages enclosed. The gain is not exact on both and is within a tolerance. This means that the gain on one part might 94 and the other might be 104 for example and so the phase inverter will be unbalanced.
That, however, assumes that the circuit itself and the OT is in perfect balanced which it never is in any amplifier.
Therefore an unbalanced 12AX7 may actually balance the stage, and vise versa a balanced one might throw it off.
That brings us to what sounds good. 99% of your audience will not notice any tonal difference.
Most guitarists with well tuned ears will notice a difference but not be able to state whether the difference is actually "better" or not.
In general a perfectly balanced PI stage sounds a little more sterile and HiFi, whereas a bit of imbalance brings out some warmth and sweet harmonic content.
As mentioned earlier a balanced PI valve may bring the stage more in balance or make it even further out and so wont give consistant results in different amplifiers and therefore, IMO, is a waste of money, especially when you consider that your target definitley will not notice.