You may have noticed that our tube offerings are priced to different gradings – the best, also the most expensive, grade is ‘Top 10% Best of Best Grade’ at a price premium over typical ‘factory QC pass grade’.

Is the ‘Top 10% Best of Best Grade’ worth the money? What are you paying for the best grade?

Tubes, like most bulk commodities, are graded according to their tested parameters from lab equipment. Although vacuum tubes are industrial products, they are not cookie-cutting universal exactly the same when rolling off the production line. Consider tubes like premium coffee beans: They are all coffee beans, but not all the same coffee beans, and are not sold at all the same price.

Tubes are hand-made products. Many human factors play into the final quality and lifespan of tubes. Tubes are also live creatures – they are not in static fixed state through their lifespan – they change with the environment they work in, and change itself unexpectedly like a ‘living creature’.

An example on 300B tubes:

A factory QC pass grade 300B tube can have 60-70% of full emission but still considered ‘QC pass’ by a tube factory. Our selected ‘top 10% Best of Best grade’ will have minimum 85% up to 110% of full emission. The top grade will have approximately extra 30%-50% emission (in comparison terms between the two grades) to allow your tubes last much much longer.

Additional screening of our ‘Top 10% Best of Best Grade’ also have matched transconductance to the best possible range and no other imperfections in tested specs.

Why called top 10%? Because these tubes only take about 10% of the entire tube production batch. They are rare and hard to come by, when ALL parameters considered.

This comparison on 300B grading also applies on other tube models.

If budget isn’t an issue, we as buyers would personally go with top 10% best of best grade on these high end tubes, to make sure to get the best possible commodity for longest time enjoyment. 

Hope this helps with your tube purchase selection!

Rachel @ Grant Fidelity