As a company that makes only tube preamps, we spend a lot of time answering questions about this subject.
You may have heard that certain preamps are hard on the tubes. Today’s question is… what does that mean?
High Voltage
We have seen and worked on literally dozens of different tube preamps. Many of them run the tubes at much higher voltages than we do. For example, we have seen preamps running the tubes at 250V, 300V, and even 350V. Some preamps introduce pre-regulation voltages as high as 450V.
High voltage is hard on tubes and will cause them to expire more quickly. (At Backert Labs we run our tubes at less than 120V).
Why would any company run their tubes at high voltages? Do they want you constantly running out to buy new tubes? No.
They do this to achieve certain measurement goals, such as lower distortion. We want this too, but we use advanced circuit design to achieve our goals, rather than pushing the tubes.
Powerage
As you may have heard, real “power” comes in the form of amperage, or current. Running higher levels of current through the tubes also causes them to meet their maker at an earlier date.
Our preamps subject the tubes to very low levels of current, far less than even 1/10th of an amp.
Is Backert Labs All About Tube Life?
Tube life is extended by at least 5 different aspects of our circuit design.
Are we just obsessively devoted to the longest possible tube life?
Actually, no. The fact is, these are happy coincidences. We design our circuits for the best possible sound quality. In several cases, our design decisions just happen to extend tube life.
Power Me Up, Scotty
Another major source of tube fatigue is the surge of power that goes through a tube every time the unit is turned on. At least, in certain brands.
Again, as a result of our circuit design, our preamps do not force a large rush of power through the tubes on turn-on.
Why It Matters
We use 12AU7 tubes in our linestage preamps, as these are some of the most plentiful tubes in the world.
That makes it easy, and less expensive, to experiment if you want to see what different tubes sound like.
The fact that we use only 2 tubes also helps keep costs down.
But if you don’t care about experimentation, what you mainly want is to never have to worry about your tubes.
This is why we are proud to build preamps with such long tube life. As we often say, the tubes in our units may just outlast all of us.
