Backert Labs Rhumba Extreme 1.3 Preamplifier
In my humble opinion, the two most under appreciated aspects of high-end audio are room acoustics/speaker placement and the preamplifier. These are the unsung heroes of the best sounding audio systems in the world. Speakers are generally front and center - kinda like a quarterback for a great football team. The power amplifier and the speakers complete the final circuit in audio reproduction, so the matching of the power amp and the speaker is crucial.
The audio source gets a tremendous amount of attention too. People get very excited and want to show off their new streaming system or turntable.
I, myself, have always thought that the preamp was the heart and soul of a great sounding system. You may switch speakers, which may cause you to look at a different power amp. You may upgrade your vinyl rig, purchase a new DAC or add a high-def streaming system, but usually, the preamp stays constant. My point here is that in many cases people give credence for the overall sound of their system to the source, speaker and power amp - the preamp can many times get overlooked.
The Status Quo For Preamps
There are certain companies that have consistently built impressive preamplifiers that stand on their own. One of those companies is Audio Research Corporation (ARC), going back to the SP3 in 1973 all the way to the current Reference 6. Some companies have struck gold with outstanding pre-amplifiers such as the CAT SL1 and the Audible Illusions Modulus 3A on the more affordable side. That is why when I heard that a relatively new company, Backert Labs, was building nothing but pre-amplifiers, I got excited. I thought to myself, "these guys must see things the way I do" to build an entire company on just pre-amps.
Backert Labs - The Preamp Specialists
As I already mentioned, Backert Labs only makes preamplifiers. They have two main preamp models: the Rhythm and the Rhumba. As of the time of this writing, the Rhythm 1.3 is their flagship model at $9995, and the Rhumba 1.3 is $4000. The Rhumba can be purchased with a stunning red or blue body for an additional $200.
Their new model (which is the subject of this review) is the Rhumba Extreme, priced at $6500. The Extreme version of the Rhumba claims to have much of the sonic attributes of their flagship, but in the Rhumba chassis.
There are some other differences between the Rhumba Extreme and the Rhythm such as:
In speaking with Andy, he stated that the Rhumba Extreme was developed to deliver 90% of the sound of their flagship at a substantially lower price point -- essentially their Rhythm preamp for several thousand dollars less.
Should PreAmps Have A "Sound"?
The function of the preamplifier is to:
Most audiophiles would state that the perfect preamplifier does all of the above and adds nothing to music. In reality, all preamplifiers will always affect the sound of your overall system, the key is to make sure that the sonic signature of your next preamp is something that adds to the enjoyment of the system as a whole. In the worst of scenarios, a preamp won't have the "muscle" to drive a particular amplifier. This type of mismatch (output impedance of the pre to the input impedance of the power) is the most common way preamplifiers stand out, and it's not in a good way. It's worth noting that the Backert Labs Rhumba Extreme claims to have an exceedingly low output impedance of 75 Ohms, which will drive any amplifier on the planet. With that low of an output impedance, I was a little bit shocked by the lack of headphone jack.
The preamp should also be able to stand on its own as a great audio component, not just something that mates well with the current amplifier of choice.
The Rhumba Extreme Features And Specs
The Extreme has a stereo set of fully balanced XLR and three sets of RCA unbalanced inputs. As for outputs, you get fully balanced XLR and two stereo sets of unbalanced RCA, plus a set of tape-outs. The unit offers a home theatre bypass feature, which can pass the front two channels of a video processor through the pre. Note that the unit has to be off for that function to work.
The Extreme comes with adjustable spikes for leveling and noise isolation. The top of the unit has a pill-shaped piece of Plexiglas that is easily removed by thumbscrews to access the two 12AU7 / 6189 / ECC82 tubes. Once the Plexiglas is removed, all of the innards are covered with the exception of the two tube sockets. Personally, I absolutely love the ability to easily and safely swap out the tubes. They even provide a pair of tube dampeners. This is really a tube roller's preamp.
The Rhumba Extreme also comes with a remote that only controls volume. This remote is hefty, as in really hefty. Does anyone remember the old Wadia remotes that could double as a weapon? The remote for the Rhumba Extreme is not too far behind. Seems like a little overkill for a remote that only has two small buttons, but cool nonetheless.
Unpacking The Rhumba Extreme
First Notes Of The Backert Labs Pre
The first impressions of the tonal balance of Rhumba Extreme are best described as harmonically accurate and quite neutral. Although the Rhumba did not sound overly tubey or bloated in any way, the harmonics around the music seemed to dissipate into nothingness with grace.
Lastly, I noticed that the overall gain on the Rhumba Extreme was a little lower than some other preamps. This in no way means that it can't drive amps properly or have great dynamics, it simply means that the potentiometer ends up being turned up higher to get the same volume. Somewhere in years of dealing with high end audio equipment, I seem to remember that "pots" perform better and are more linear as they get turned up higher. This leaves me to wonder if the lower gain with the incredibly low output impedance was a strategic design effort.
Change Of Systems
We set up some Dynaudio Special Forty's, powered by an Audio Research VT80. The preamp that we used for a baseline was the Rouge Audio RP-5, which is the baby brother to the critically acclaimed RP-7. After a few minutes of listening, we swapped out the Rouge for the Rhumba Extreme.
The Rhumba was decidedly better in just about every area. More dynamic with better attack, substantially better bottom end, a more defined image and much more air. The image with the Rhumba was more focused and tangible. To be fair, the Rhumba costs quite a bit more than the RP-5, so I thought we should step it up a little bit. In addition, the Rogue Audio doesn't have balanced outs - so the signal was quite a bit hotter with the Backert Labs Rhumba Extreme.
We decided to plug in the ARC LS17 SE Preamplifier as it is a wonderful sounding preamp by a company that strives to build some of the best sounding preamps you will find. Although a couple of years old, the LS17 SE hit the market as a scaled-down Ref 3 and punches way outside of its price range. The LS17 SE also has balanced outs for a more direct head to head comparison.
New Brand Versus Solidified Veteran
The difference in sound between the two preamps was not subtle. This is where things get to be a matter of subjectivity. The ARC sounded slightly more focused but seemed to have a "halo" around the image. The best way I can explain it is the audible equivalent of having your center image inside of a water bubble, with a slight glow around the edges. This specific tonal attribute, although very pleasing to the ear and sharp, doesn't seem quite as realistic as the more airy, Rhumba Extreme, where the image seemed to float in space.
The Rhumba's harmonic balance was excellent. The slightest differences in timbre were drawn out and put on a platter for your musical enjoyment. The Rhumba was able to deliver a deep, multi-level image with a warm but airy tonal balance. Not ever sounding tubey, but really delivering on harmonic decay and simply really pleasant to listen to.
One of the few definitive places where the Backert Labs stood out over the ARC was the accuracy of the bottom end. Where the LS17 SE sounded a little more rounded and tube-like, the Rhumba Extreme was solid, almost solid-state like. Transients were fast and energetic. The floor toms from Jennifer Waren's version of Bird on a Wire really stood out as powerful and authoritative without any bloat.
Roll Your Own - The Beauty Of Tube Rolling
I had already kept the demo unit longer than I should have and was feeling the pressure to get it boxed up and sent back. A day or so before I was planning on packing it up, Andy Tebbe with Backert Labs reached out to ask if I had a chance to try any different tubes. Although I love the ability to change the tonal balance of tube equipment by experimenting with different tubes, I did not have any quality 6189s to tube roll with. Andy agreed to send me a couple of sets of tubes they'd had good results with.
I was super stoked, as I now had a good excuse to spend more time with the Extreme.
About a week later, I received some NOS Mazda 12AU7s in the mail. He also said that I had a matched pair of NOS Mullards on the way to me from a Canadian company called MullardTubes.com. Tube rollin' with the Backert Labs Rhumba is a breeze. All you do is power it down, unscrew the top thumbscrews, pull the old tubes out, and put the new tubes in. You don't need to take the unit apart or feel that you may break something to quickly put different tubes to the test. Easy peasy.
Upon putting in the Mazdas, the difference was stunning. I have already spoken quite a bit about the outstanding harmonic decay I have experienced with the Rhumba Extreme; with the Mazdas that improved even more. Really a striking improvement.
Because swapping tubes is so fast, you can easily make direct A/B comparisons and really fine-tune your system. Swapping tubes is a relatively inexpensive and fun way to tweak out your system. You'll notice very big results and the nifty little opening in the top of the Rhumba is just begging you to swap tubes. As for the NOS Mullards, I ran out of time. The good news is the Rhumba Extreme comes stock with a set of perfectly decent "new issue" Mullards distributed by New Sensor.
Final Words On Sound And Value
As many audiophiles have pointed out, there is a level of diminishing returns when you start reaching for the ultimate in audio equipment. The price range of the Rhumba Extreme, I feel they have hit a "sweet spot" in the price range of high end preamps. They are priced on the low end of the high end while being a formidable opponent to any pre at any price. As an added benefit, the extremely low output impedance lets the Rhumba be paired with amplifiers that other preamps my struggle to drive.
In my humble experience, the Rhumba Extreme is a serious contender if you are looking for a top notch preamplifier that has a neutral presentation, excels in macro and micro dynamics and gets the harmonics of delicate music right. They seem to get everything right, while not having to take out a second mortgage on your home. If you are looking to bring new life into your system by upgrading your preamp, you would be doing yourself a disservice if you don't have the Rhumba Extreme on your shortlist.