Backert Labs The Rhythm 1.1 preamplifier

Backert Labs The Rhythm 1.1 is very interesting tube preamplifier with elaborate explanation about all the tech implemented below. “The Rhythm 1.1 is a single-ended line stage preamp that provides a new level of audio enjoyment by employing radically new technology.”


Designed, machined and assembled in Pennsylvania, the Rhythm 1.1 utilizes two 12au7 tubes in its gain stage.  In addition to its remote volume control, the Rhythm 1.1 has a balance control, mute switch, mono switch, five sets of RCA inputs and two sets of RCA output jacks in addition to a Record Out.  Its handy tube access door allows tube changes with no tools, just the touch of a finger.  And the pleasing glow of the volume knob’s LED indicator points out where volume is set.

Sound at a Glance

Acquire the Rhythm 1.1 if you want your music to come alive, if you want toe-tapping rhythm like you’ve never heard before – especially from a tubed unit – and if you want your music to have all the clarity, accuracy, and beauty that is present on your source material.

The Rhythm 1.1 tubed preamplifier provides exceptional sound quality, in several key areas.


So often ignored by audio manufacturers, it is rare to see rhythm even mentioned in product literature.  At Backert Labs, we believe that accurate rhythm, the precise timing of your music, is essential to experiencing a live performance in your living room.  With accurate rhythm, music becomes more compelling.  More “right now”.  And of course, with many kinds of music, more fun and toe-tapping.


With its radical gain stage and the advanced capacitors in its power supply, we believe the Rhythm 1.1 presents the most accurate dynamics of any stereo component you can buy.

Speed and attack

It sounds a bit odd to say that an amplifier is “fast”.  No, the Rhythm 1.1 will not speed up your music.  But it will provide lightning-fast response.  This applies to the very front edge of each sound, and to the immediate cessation at the end of each sound.  From powerful drum hits, to a sudden wall of emotion from a fortissimo chorus, the Rhythm 1.1 starts, and stops, on a dime.  Its speed and attack are due to the Rhythm 1.1’s gain stage, the technology driving its GreenForce power supply, and the V-Cap™ capacitors in its power supply.


While many preamplifiers can present a beautiful tone, the Rhythm 1.1 digs deeper, and shows you the inner tone of an instrument or voice — the slightest wavering of a trumpet, the woody details of that particular bass violin, the quiet sigh of a female vocalist.  We think the Rhythm 1.1 will convey more about the tone of your favorite music than you have heard before.


The design of Bob Backert’s GreenForce power supply lifts the accurate presentation of a massive soundstage to a new level.


With its point-to-point circuit connections and absolutely *no* aluminum electrolytic capacitors, one of the first things you will notice about the Rhythm 1.1 is its striking clarity, its open, “right there”, true-to-life presentation of your favorite music.

Technology At A Glance

The Rhythm 1.1 uses an amplification circuit (“gain stage”) unlike any other.  The way it amplifies is extremely easy on your tubes, running at a constant current and a remarkably low voltage (150 volts) for the blackest backgrounds possible.

Its internal parts are of the highest quality, including the best capacitors ever built into a power supply (V-Cap™ capacitors), a first in audio made possible by Bob Backert’s patented GreenForce™ power supply.   Although every other active preamp in the world uses them, the Rhythm 1.1 uses no aluminum electrolytic capacitors in the power supply or anywhere else.

The power supply:

GreenForce power supply

The power supply that runs most audio equipment today is called a “linear” supply.  It was designed in the 1920s, when most people first used electric devices in their homes.  It hasn’t changed much.  Recently, some audio devices started using something different – a “switching” supply.  That design was developed in the 1950s.  The Rhythm 1.1 preamplifier uses the new GreenForce™ power supply.  Bob Backert patented GreenForce in 2013.

GreenForce is the only power supply in the world that can run entirely on V-CapTM capacitors, the finest type of capacitor in audio today.  More about that here.  In contrast, the power supplies in almost all audio equipment use electrolytic capacitors, the worst quality capacitor made today.  It’s not because they want to.  It’s because they have no other choice.  With GreenForce, that changes.  Let’s talk about why “Green” and “Force” are in the name of this new kind of power supply.


GreenForce allows Backert Labs to eliminate electrolytic capacitors from the power supply.  Bob Backert wanted to achieve this because electrolytic capacitors are famous for their disappointing sound quality.  That sound quality problem is why many manufacturers use small, high-quality “bypass” capacitors along with their electrolytics.  But why do they use electrolytics at all?  Because they need very large capacitor values that only electrolytics can provide.  GreenForce uses much smaller values, allowing high quality capacitors to power the unit.  In addition to sounding better, eliminating electrolytic caps is also a win for our environment.  That’s because electrolytic capacitors contain chemical sludge that is classified by  manufacturers as hazardous waste.  The power supply is where you’ll find the largest electrolytic capacitors in any piece of audio gear.  By eliminating them, the GreenForce power supply makes the Rhythm 1.1 “green” in a whole new way.  More on the elimination of electrolytic capacitors here.


Unlike traditional power supplies, in which a capacitor passively bleeds power out when the amplifier demands it, GreenForce is the first and only power supply to actually force power into the load (the amplifier) at all times.

The Benefit:  This makes GreenForce more nimble, more accurate than conventional supplies.  This is key in immediately responding to changing current demands, such as the larger amount of current required to reproduce a loud bass drum.

Example:  Imagine that a power supply capacitor is actually a barrel full of water (the water is the capacitor’s power).  A hose coming from the bottom of the barrel lets the water drain out.  This is the way that typical audio components get their power — it “drains out” from the power supply capacitor.  When it gets empty enough, the barrel / capacitor is refilled with more water / power.  Now imagine that the barrel is low on water at this very moment.  And right now, a powerful bass drum strike happens in your music.  Because the weight of the water is less, the pressure of the water coming out of the hose will be weaker at this critical moment.  The capacitor’s ability to immediately provide the required power for that bass drum strike will be impaired.  Full pressure will only be possible a moment later, after the barrel has been re-filled with water.

GreenForce changes that.  GreenForce is like placing a lid on the water, and steadily pushing the lid down as the water comes out of the hose —  forcing the water out at all times.  Now, the pressure of the water coming from the hose will remain steady, even when the barrel is getting low on water.  This is similar to the power produced by the capacitor in GreenForce.  No matter how much power your music calls for, and no matter when, it’s right there.  Power with true force behind it, at all times.

The Sound

The GreenForce™ power supply gives sound equipment improved dynamics — the lightning-fast changes in volume that all instruments and singers on a recording are constantly employing to give music its drive and emotion. GreenForce also improves soundstage, with a more accurate and spacious physical presentation.


The GreenForce power supply gives the Rhythm 1.1 something else as well — rhythm.  Plucking, swinging, rocking, every which way.  Your favorite music will pulse, propel you, move you, like never before.

Why Power Supplies Matter

The power supply is surprisingly critical to the accurate reproduction of music.

Power supplies are more critical than you might think.  A power supply in a stereo amplifier doesn’t just provide energy to let the amplifier function.  The power supply IS the music that you hear.

It would be reasonable to think that the music signal comes into an amplifier, gets amplified, and then gets directed to the output jacks.  But this is incorrect.  In fact, the amplifier copies the music signal, and it is the copy  that is sent to the output jacks.  The “blank page” that receives the copy is the power supply signal.  Once the music signal is copied onto the power supply signal, the power supply signal is then sent to the output jacks.

The power supply signal, therefore, literally becomes the music that you hear.  This is one reason that the power supply is so important.  It is why the capacitors producing the power supply signal are so important.  And it’s one reason that Bob Backert invented the GreenForce™ power supply.

Tech Talk

GreenForce uses smaller capacitor values.  To put that in context, the values in a GreenForce power supply are usually around 0.5% of the value required by a normal power supply.  A typical tube preamp might use 100 or 200uF in the power supply, or even thousands of uF (microfarads, a measure of capacitance).  Our Rhythm 1.1 uses less than 1uF.  GreenForce has nothing in common with a switched mode power supply, and shares only a few similarities with linear power supplies.  It achieves isolation from the AC line the same way a linear power supply does, by starting with a typical transformer.  GreenForce provides better current linearity, feeding the regulator with “right now” current more nimbly than other power supplies.  For more, visit the GreenForce website, here.


Line stage tubed preamp, single-ended
5 inputs, 2 outputs, 1 “Rec Out”, all RCA
Balance control, mute switch, mono switch, remote volume control
Tube complement:  2 X 12au7, accessible via tube access door on top panel
Phase:   phase inverting
THD+N: 0.032%
Gain:  9dB (we can adjust this to suit your specific system)
Frequence response: 1.5Hz to 320kHz
S/N ratio: 98dB (90dB referenced to a 1V output)
Input impedance: 55,000Ω
Output impedance: 150Ω
Crosstalk: 78dB
Power consumption, idle: 23W
Power consumption, maximum output: 24W
Dimensions: 17 x 12 x 4 inches
Weight:  23 lbs