Class A, No Feedback Design: Our preamps are Class A and uses 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.
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 one.
Unique tube access door: Tired of having to find your screwdriver every time you want to change tubes? With the touch of a finger, the Rhythm 1.1’s tube door flips open and allows easy access to your tubes (after you have turned off and unplugged the unit, of course). Our new model uses two handy fasteners to keep the tube door in place — again, no tools required.
Beautiful hi-tech exterior: With no screws, fasteners or ventilation slats visible anywhere, our preamps look as high-tech as they are inside.
Low output impedance: The output impedance of our preamps measures a low 150 ohms. This means they will work perfectly with any power amplifier, whether tubed or solid-state.
Minimal capacitance: Bob Backert’s philosophy is that capacitors color the sound of your music. To that end, he uses dramatically less capacitance than other manufacturers. This requires careful thought and technical ingenuity, but it’s worth it. A power supply for a typical tube preamp might have capacitors totaling 100 or 1,000 uF. Our preamps use less than 1 uF. The regulator in a typical preamp might have 30, 100 or even 500 uF. Our regulator uses 1.1 uF.
A single stage of amplification: For the highest possible accuracy and sonic purity, our preamps use one stage of amplification only. A side-effect of using a single gain stage is that our models invert phase. More on that here.
High quality attenuator and balance: The Rhythm 1.1 uses premium TKD volume and balance controls. Our new model uses a high quality Alps volume control.
Mono switch: Our preamps include a handy mono switch on the front panel.
Mute switch: A red LED alerts you to the unit’s muted status.
Toroidal transformer: Our preamps use a custom-built toroidal built by Avel-Lindberg of Connecticut, with special features designed to eliminate interference with the audio signal.
Record Out: An output circuit on the rear panel provides full strength unattenuated audio signal for tape recording, CD burning, headphone amplifiers, etc.
Extremely easy on your tubes: Our gain stage is designed to baby your precious tubes with minimal and constant current.
Point-to-point wiring: The Rhythm 1.1’s circuit board is hand-soldered, with point-to-point wiring for the power supply, regulator, gain stage, tube connections, and output stage – every aspect of the preamplifier that handles, or even comes close to handling, music signal.
And our favorite: The Rhythm 1.1 and our new model are both designed and built in the USA.