The section of a preamplifier that amplifies your music is called the gain stage. In a tube preamp, the gain stage circuit works with the tubes to amplify music.
Sound
When people hear our gain stage for the first time, they tend to focus immediately on the music. It’s not about better treble, or better bass. Our approach is so new, such a complete overhaul of the typical tubed amplification circuit, that audiophile phrases become unimportant. What matters is the performance that is happening, right now, in front of you.
Life-like dynamics. Spaciousness. Real-life clarity. No sweeteners, no thickeners, no “warmed up” midbass. Our gain stage delivers music as it really sounds.
Tech Talk
Our gain stage has several technical features:
Low Voltage, Low Current: Backert Labs preamps are easy on your tubes because we do not “run them hard”. We are not aware of any other manufacturer that runs tubes more gently than we do. Please note that this is not our ultimate pursuit — our first goal is the finest sound quality. It just so happens that as we designed our gain stage, we found that the design with the greatest linearity and most faithful amplification is very, very gentle on the tubes. It is a happy coincidence.
Automatic Bias Correction: Unlike other preamplifiers, our Rhythm, Rhumba Extreme, and Rhumba Xphono preamps automatically adjust the bias of your tubes, continuously.
- Just bought a new pair of NOS tubes? Once you put them in, the preamp’s bias is immediately adjusted specifically for them. Every pair you insert will again receive a specific bias, customized just for them. Automatically.
- Using the same tubes for 10 years? Bias will need adjustment to a small degree as they age, and to a larger degree toward the end of their life. Bob Backert’s gain stage does that.
No Cathode Follower: Many tube preamps use an extra tubed circuit after the gain stage, called a cathode follower. This circuit is intended to lower the preamp’s output impedance. Because a cathode follower can impair the accuracy of a preamp’s dynamics, we do not use a cathode follower. We don’t need to, because our gain stage is naturally very low in output impedance.
For more about the technical side of our preamps, please see More Goodies.