BACKERT LABS

Rhumba Extreme™ 1.4 Linestage Tube Preamp

The Rhumba Extreme™ tube preamp gives you a way to get a Rhythm (our flagship linestage preamp) at a lower cost. How? We put almost every bit of the Rhythm preamp inside the less-expensive Rhumba chassis. This is the Rhumba Extreme.

On the outside, it’s identical to our more affordable Rhumba, except for 5 things:

• We put a blue LED on the volume knob, similar to the Rhythm, so you always know where the volume is during late night sessions.
• The cut-outs on the left and right side of the front plate have a mirrored stainless steel background.
• Feet: the Rhumba Extreme features the same IsoAcoustics “Gaia” feet found on our flagship Rhythm preamp.
• The word “Extreme” appears next to the serial number on the rear panel.
• The bottom panel of the chassis is made from solid brass. We found that solid brass as a support for the circuit board gave the Extreme a slightly more holographic and natural presentation.

On the inside, the Extreme is much closer to a Rhythm than it is to a Rhumba. That’s the whole point of the Rhumba Extreme: to make it much more affordable for music lovers to hear what our flagship Rhythm preamp sounds like.

Rhumba Extreme vs. Rhumba

What are the goodies inside, that make the Rhumba Extreme so extreme, compared to the “regular” Rhumba?

• A fully dual-mono power supply – including dual-mono regulators – so the Rhumba Extreme has two full GreenForce power supplies, one for the left channel, and one for the right channel. Each power supply gets its own discrete regulator.
• Our famous auto-bias circuit for the tubes, which keeps your tubes happy with the perfect bias level at all times. This will make your tubes last longer, and it will prevent tubes that have unusual bias requirements from sounding bad due to being deprived of the bias they want.
• High quality Jantzen Silver polypropylene capacitors for the power supply. Our ability to use such high quality capacitors to run the power supply is owed to the design of Bob Backert’s patented GreenForce power supply.
• Improved capacitors in the regulator.

Rhythm™ 1.4

“You want this. Trust me – you want it bad.” 

That was the reaction of Ron Brenay, founder of NewRecordDay.com after hearing the Rhythm preamplifier.

In his June 2025 Stereo Times review, veteran reviewer Terry London concluded: “Based on what I shared in this review, I decided to purchase the Rhythm 1.4 because I didn’t want to give up the fun and exceptional musical enjoyment it creates in my system.”

The Rhythm 1.4 is our flagship. It looks just like the previous Rhythm 1.3, but it sounds…. better. Silky, powerful, dynamic, and huge. Our finest linestage tube preamplifier, it sells for $12,900.

“The long and the short of it is that the Rhythm is completely quiet, highly resolving, explosively dynamic, and sounds freakin’ amazing. I suppose you could say that I’m a fan.”

That was Scot Hull, the founder of Part Time Audiophile.

Features

• Fully balanced XLR inputs (2) and output (2): for those of you with long cable runs or who feel that balanced XLR just sounds better
• Incredibly long tube life: Our proprietary five-step design process for the gain stage extends the lives of your tubes, to the point where they might just outlast all of us
• Brass: We have found that incorporating a solid-brass bottom panel to support the unit (and the circuit board) provides more holographic and more natural sound quality.
• Dual-mono power supply: left and right channels have their own power supplies and regulators and their own separate windings in the power transformer, for the ultimate in separation, imaging and accuracy
• Highest-quality output capacitors: The highly seductive V-Cap ODAMs handle output duty. These are not fluoropolymer caps (the material found in no-stick frying pans), because we find that material to be best suited for the demands of the power supply. To our ears the V-Cap ODAM polypropylene capacitors are extremely revealing, involving, accurate capacitors.
• “Crazy-good” power supply capacitors: the above-mentioned and famously dominant fluoropolymer type of capacitor drives our GreenForce power supply. These exotic capacitors are unheard-of for use in an audio power supply. In any any power supply at all, actually. And yes, they are crazy-good.
• Improved circuit board: features design upgrades that improve grounding and separation throughout
• Improved stock tubes: our special NOS tubes provide maximum pace, dimensionality, dynamics and resolution
• Our latest circuit: last but not least (because it’s probably the most important point), the Rhythm’s gain stage and power supply regulator designs benefit from our latest research.

Designed, machined, and assembled in Pennsylvania, the Rhythm 1.4 utilizes advanced patented technology in its power supply, and highly unusual technology in its gain stage.

Sound at a Glance

Acquire the Rhythm 1.4 if you want your music to come alive, if you want toe-tapping rhythm, and if you want your music to have all the clarity, accuracy, and beauty that is present on your source material.

Technology at a Glance

The Rhythm 1.4 uses an amplification circuit (“gain stage”) unlike any other. The way it amplifies is extremely easy on your tubes, running at an exceptionally low voltage and using other circuit innovations for the blackest backgrounds possible, as well as the longest tube life you will find anywhere.

Its internal parts are of the highest quality, including the best capacitors ever built into a power supply (fluoropolymer capacitors, which is the famous material used in no-stick saucepans), a first in audio made possible by Bob Backert’s patented GreenForce™ power supply.

Amazingly low output impedance (<80 ohms) means that the Rhythm combines beautifully with any power amplifier. The transformer is toroidal and custom-made for us, providing separate windings for each channel. The Furutech IEC connector allows you to experiment with various power cords. And the premium jacks on the rear panel are so sturdy and widely spaced, the Rhythm 1.4 can handle whatever interconnects you may select.

Rhumba™ 1.4

The Rhumba 1.4 is our most surprising tube preamplifier. Fully balanced input and output. Jaw-dropping sound. The Rhumba sells for $5,000.

“The most exciting aspect of the Rhumba is the lively, dynamic aspect of its sound.”

–TONEAudio Magazine

At $5,000, the Rhumba 1.4 linestage preamp has the same basic circuit design as our $12,900 Rhythm 1.4 flagship, including fully balanced XLR input and output. That also includes the same power supply design — our patented GreenForce.™

All in a gorgeous chassis. Like the Rhythm, the Rhumba is designed, machined, and assembled in the U.S., with NO farming out of the solid aluminum chassis to other countries.

From its debut, the Rhumba has wowed listeners. See reviewer Terry London’s raving preview of the 1st-generation Rhumba 1.1 here including his stunning conclusion, “might be the best deal in high-end gear of the 21st century”.

The Rhumba 1.4 has the following new features:

• two fully-balanced XLR inputs, rather than just one
• two fully-balanced XLR outputs, rather than just one
• improved circuit developments in the regulator portion of the power supply, which provides a larger soundstage
• improved circuit design in the gain stage, which provides a higher-resolution, more 3-dimensional listening experience
• improved stock tubes, which are NOS American-made tubes that are bursting with resolution and dynamics
• a new 3-button remote control that now includes a “mute” button

Features, Features...

Other features carried over from the Rhythm flagship include no use of negative feedback, pure Class A design, the luxurious and heavy remote volume control, mute switch, mono switch, balance control, REC OUT jacks, Home Theater Bypass jacks, custom-made toroidal transformer and Furutech IEC inlet to allow you to experiment with various power cords.

The Rhumba 1.4 has 10dB of gain.

The Sound

The Rhumba sounds remarkably close to the company’s flagship, the Rhythm. Although it is less than half the price of the Rhythm we were able to bring the Rhumba’s dynamics, fun factor, overall musicality and punchy, involving timing extremely close to the Rhythm’s.

These sonic characteristics form part of the company’s mission. Bob Backert has said, “When you enter a club or restaurant, it’s usually pretty easy to tell whether the music is live, or being played on a stereo. I wanted to make it much harder to tell the difference.”

To do that, we focus on the accuracy of two things: dynamics and rhythm. Our technical innovations have brought us significantly closer to the goal of reproducing truly live sound.

Compared to the previous versions of the Rhumba, the Rhumba 1.4 features progressively “bigger” sound with greater weight and more articulate midrange.