Every Backert Labs preamp has the following features:
Easy on your tubes: Unlike many brands which are “hard on your tubes,” our gain stage is designed to baby your tubes. We know of no other manufacturer who is as gentle on a pair of tubes. Your tubes should last many, many years if not forever.
Home Theater Bypass Input Doesn’t Use Your Tubes During Movies: Those who have a home theater mixed in with their high-quality stereo systems usually run into a problem: those big front speakers are fed by a power amp, which is fed by their home theater processor, during movies…. and it’s fed by their stereo preamp when they listen to music. But nobody wants to go behind their power amp every time they switch from movies to music, to change the cables that feed the power amp.
The Home Theater input jacks on Backert Labs linestage preamps solve this.
A pair of RCA jacks on the rear panel of every Backert Labs linestage (called “Home Theater Input”) receives interconnect cables from the front left/right preamp outputs of your home theater receiver.
Simply turning off your Backert Labs preamp turns it into a bypass, so that your power amp now receives sound signals from your home theater processor. Since you activate Home Theater mode by turning your Backert Labs preamp off, you won’t be using your preamp’s tubes while you watch movies. Most other brands require you to leave your 2-channel stereo preamp *on* while watching movies.
Home Theater mode works whether your Backert Labs is connected to your power amp via RCA or fully balanced XLR connectors (in fact, if you are using both XLR and RCA outputs to connect to multiple power amps, both outputs will receive signal).
Class A, No Feedback Design: Our preamps are Class A and use no negative feedback — neither global, nor local. Feedback is used by many manufacturers to achieve certain measurement goals, but it adds phase distortion and impairs dynamics and rhythmic accuracy, so we achieve these goals using methods that we have devised which do not employ feedback.
No Cathode Follower: Many tubed preamps use an extra tubed circuit after the gain stage, called a cathode follower, to lower the preamp’s output impedance and to protect the gain stage from detrimental interactions with the preamp’s output cables and the power amp. Because cathode followers can impair the accuracy of a preamp’s dynamics, our preamps get these things done without using a cathode follower.
Unique tube access door: Tired of searching for your screwdriver every time you want to change tubes? With the touch of a finger, the tube door on our preamps opens and allows easy access to your tubes.
Beautiful hi-tech exterior: With no screws, visible from the outside, and no ventilation holes visible anywhere to detract the eye from our modern designs, our preamps look as high-tech as they really are inside.
Low output impedance: We keep the output impedance of our linestage tube preamps at a very low and very useful level of less than 75 ohms. This means our linestage preamps will work perfectly with any power amplifier, whether it is tubed, or solid-state.
Minimal capacitance: Capacitors are necessary in stereo equipment. But we don’t think they sound very good. They make music sound grey, compressed and “like you’re listening to a stereo”. So we have reduced them as much as possible.
We have reduced them so much that engineers sometimes don’t believe us when we say how little capacitance we use. That’s because Bob Backert’s patented power supply, GreenForce™ and his special regulator use a tiny fraction of the capacitance that a typical preamp would use.
What do we mean by a tiny fraction of the capacitance? Well, a typical tube preamp might have 500 or 1000 uF in in the power supply. (uF means microfarads, which is a measure of capacitance). But many preamps go further and have thousands of uF, or tens of thousands, or even millions of uF in their power supplies. The Rhumba’s power supply uses less than 1 uF. The Rhythm and Rhumba Extreme have dual mono power supplies. They total less than 1.5 uF of capacitance.
A single stage of amplification: Our linestage preamps use one stage of amplification only, for the highest possible accuracy and sonic purity.
High quality attenuator and balance: Our linestage preamps use only the highest-quality ALPS analog volume and balance controls — never digital.
Mono switch: Our linestage preamps include a handy mono / stereo switch on the front panel.
Mute switch: All of our preamps feature a mute toggle switch on the front panel. A red LED illuminates to alert you when the preamp is in muted status.
Toroidal transformer: Our preamps use a toroidal transformer custom-built for us, with special features designed to eliminate interference with the audio signal.
Record Out: A pair of RCA output jacks on the rear panel of our linestage preamps provides unattenuated audio signal for tape recording, CD burning, headphone amplifiers, or other uses. The output of these REC OUT jacks will equal the output of your source (DAC, CD player, etc).
And our favorite: All of our preamps, including circuit board and chassis, are designed and hand-built by us, in the United States of America.