Quest For Sound - High End Audio

Backert Labs

Rumba 1.4

Improvements from the Rhumba 1.4

New dual-wafer selector switch from the Rhythm improves separation
Now 5 inputs (was 4)
Now 4 outputs (was 3)
Now 2 fully balanced XLR inputs and 2 fully balanced XLR outputs
Still has 3 RCA inputs and 2 RCA outputs
New circuit designs in power supply regulator and gain stage, for increased clarity and openness

The Rhumba has always featured a convenient tube access door to let you change tubes easily. The Rhumba 1.3 eliminates the detachable thumbscrews on the tube door, so it’s even easier now — there’s nothing to get away from you.

Other improvements:

circuit developments in the power supply and gain stage that provide a more 3-dimensional listening experience, with improved imaging

these changes also provide improvements to liveliness, warmth and immediacy

a new “mono/stereo” switch on the front panel, a feature taken from our flagship Rhythm preamp, which can be helpful to those who listen to mono records or CDs

improved stock tubes – we now use the Mullard reissues, which are unbelievably good for their real-world prices

Features, Features . . .

Other features carried over from the Rhythm 1.3 include fully balanced XLR input and output, no use of negative feedback, pure Class A design, a luxurious remote volume control, mute switch, balance control, REC OUT jacks, Home Theater Bypass jacks, toroidal transformer and IEC inlet to allow you to experiment with various power cords.

The Rhumba 1.3 has 8dB of gain (we can adjust this to suit your specific system).

The Sound

The Rhumba sounds remarkably similar to the company’s flagship. Although it is about 1/3 the price of the Rhythm we were able to bring its fun factor, its detail retrieval and its harmonic richness 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 easy to tell whether the music is live, or being played on a stereo. The mission I set was to make it impossible to tell the difference. To do that, we focus on the accuracy of two things: dynamics and rhythm. Several of our technical innovations have brought out audible improvements in these areas. As a result, I believe we have made significant progress toward the goal of reproducing truly live sound.”

Building on the original 1.1, the 1.2 and 1.3 models feature progressively “bigger” sound with greater weight, more articulate midrange and more precise imaging.

The Power Supply

One part of the Rhumba that improves timing and dynamic accuracy is the power supply. Patented by Mr. Backert, GreenForce™ is the first completely new kind of power supply since switching supplies were invented in the 1950s. Contrary to other designers’ seemingly unending desire for more power (i.e. larger capacitor values) in the power supply, Bob Backert wanted to eliminate capacitors entirely, if possible, because of their detrimental effects on timber, timing and dynamics. GreenForce allows the power supply to use almost no capacitance, and therefore far higher quality capacitors (in the case of the Rhumba, high quality polypropylene capacitors).

The way the power supply works is also key: it’s very different, because it actively pushes power into the amplifying circuit, instead of passively bleeding out power as the circuit demands it. That ‘push’ makes GreenForce more nimble in responding to power demands from musical recordings. This improves the accuracy of rhythm and dynamics.

GreenForce gets its green “cred” by shunning typical power supply parts (electrolytic capacitors) that contain environmentally unfriendly chemicals, instead using environmentally neutral “film” capacitors.

Built in the U.S.

Like the Rhythm, the Rhumba is designed by veteran circuit designer Bob Backert, and assembled in the U.S. under the close supervision of his son, Chief Operations Officer Gary Backert.

Tubes

Two 12au7 tubes are utilized for the gain stage, accessible by a convenient transparent access door that highlights the warm glow of the tubes through the top panel. The Rhumba comes with Mullard tubes.

Gain Stage – “Dynamic Linearity” Circuit

As in the Rhythm, the gain stage features a unique tube support circuit that allows more accurate dynamics, lower distortion and low output impedance. These benefits are achieved without resorting to common tools such as negative feedback and cathode followers, which Mr. Backert feels are detrimental to sonic accuracy.