Feliks Audio Espressivo
A Foot Tappin', Head Shakin' Tube Amp
INTRODUCTION
A Diamond In The Rough
Feliks Audio is a family company based out of Lubliniec, Poland. Their specialty –tube amps. Many will already be familiar with their fabled Elise, but few may know about its older sibling, the Espressivo. Overshadowed in a sense by its overachieving younger brother, the Espressivo has more or less faded into anonymity. It’s not particularly hard to see why the Espressivo never went mainstream –it is an understated amp with little by way of features or specifications. However, looking past these modest characteristics, one will find an amplifier that is nothing short of a hidden gem. Coming in at a modest $ 349.00 USD (the shipping/ import fees might set you back some), the Espressivo sounds plain excellent with the right cans –and frankly it could’ve been priced higher. It’s an exacting mix of musicality and dynamism that makes for an amplifier worthy of commendation.
Disclaimer
The Feliks Audio Espressivo was provided directly from Feliks Audio for the purposes of this review. I’ve been told that I can keep it due to the expensive back and forth shipping costs (I do appreciate it) and have now had it on hand for slightly over three weeks. I am neither a paid affiliate nor an employee of Feliks Audio. In addition, I do reserve the rights to the media used in the review, so do contact me if you wish to reproduce any part of the writing or photography seen here. Apart from that, I thoroughly enjoyed this amplifier and hope that y'all like this review. It can also be found on my blog here. Apologies to those who chanced upon this review in its early stage, I accidentally clicked enter twice, causing the form to submit before I was done moving everything over from Word.
PACKAGING AND ACCESSORIES
The Espressivo arrived in a good-sized cardboard box. The only indication of it being a Feliks Audio product was the tape on the front, which carried the company name and logo. Opening up the box, I found the amplifier encased in large Styrofoam blocks and marshmallows. There’s a short user’s manual and the 4 included tubes. For my package, I did happen to receive two extra sets of tubes –the 6N5P and the 6N1P-EW. The Feliks Audio amp is built-to-order and since it isn’t a huge operation, usually has a lead-time of a week or two. The wait though is completely worth it.
BUILD AND DESIGN
The Espressivo is larger than it looks in the photos. Opening it up, I realized that this would take up more desktop space than I had been ready to make available. It was heavy too. The design of the Espressivo is very nice. It’s got wood accent panels on the sides that come in three colors: alder, brown, and black (pictured is the brown version). There’s a nice grain to the wood and it definitely feels high quality. The rest of the amplifier is metal. Placed at the front are tubes (stock – 6N1P & 6N6P) and at the rear the toroidal transformer enclosure. Once of the things that I did note was that the price and tube setup of the Espressivo is identical to that of the Schiit Valhalla. I don’t have the latter on hand, so I’ll leave that thought here –maybe a Valhalla owner could chime in.
The volume pot is heavy and well built. The indicator is a small black notch at the flare of the pot, which is hard to see in dimly lit conditions. The dial markings are a nice touch, and make it easy to find one’s way around (would’ve been even better with markers at the cardinal points). The font on the front panel is little weird and slightly too big, but it’s not intrusive enough to be a major aesthetic issue. Next to the volume pot is the input selector, which has a nice tactile feel to it. The rear panel features three line-inputs, and one pre-amp out. Directly to the right is a nice large power switch to turn the unit on and off. Overall, it’s an understated but fairly elegant design, and certainly looks nicer than many of its similarly priced counterparts.
TECH AND SPECIFICATIONS
At the heart of the Espressivo are two sets of NOS tubes. Stock 6N1Ps act as driver/pre-amp tubes, and can be safely replaced with E88CC, 6N23P, 6DJ8, and 6922. I’ll add to that the 6N5P and the 6N1P-EW. The power tubes are the 6N6P, and the only recommended alternative is the 6N6P-1. There’s no exact output impedance printed on the manual, so I decided to ask the team at Feliks Audio –who subsequently responded that it is slightly under 100 ohms. The first thought that came to mind was how this would affect the damping factor and interactions with different cans. The RMAA may be informative in this sense.
I guess the following could almost become a disclaimer of sorts. RMAA results are only as good as the equipment used to perform the tests, and there has been a decent amount of coverage on its limitations and weaknesses. Consider it as a broad proof-reading of published technical specifications. I’m ranging THD readings from 0.041 – 0.052 range, and an intermodulation distortion (plus noise) of around 0.042% for the Espressivo. Currently, I am utilizing an Asus Xonar U7 external sound card (line-in mode). The ADC is a Cirrus Logic CS5361-KZZ that is capable of 24/192 w/ a 114 dB dynamic range. It uses a 5th order MBT Delta-Sigma Modulator, and attains low levels of noise and distortion. For those curious, the DAC is the equally capable CS4398-CZZ. Please find my results below. After reminder - the 470 ohm load is the R70X, and the 39 ohm load is the MH40.
Technical Specification
Input Impedance: 100 kOhm
Frequency response: 15 Hz - 45 Khz +/- 3 dB
Power output: 400mW
THD: 0.4 % (300 ohm, 20 mW)
Optimal headphones impedance: 100 - 600 ohm
Headphones output: Jack 6.3mm
AC: 230V/120V (power cord included)
Weight: 3.5 kg (7.7 lbs)
Dimensions: 330x220x140 [mm] (13x8.7x5.5 [inch])
Stock 6N1P Tubes (No Load)
Relative Comparison Of Different Tubes (No Load, See Labels) - Vertical Scaling Decreased
Relative Comparison Of Different Tubes (470 Ohm Load, See Labels) - Vertical Scaling
Decreased
-65NP is the the topmost graph (blue) and the one that is behaving slightly differently.
Stock 6N1P Tubes (39 Ohm Load) - Not So Good
SOUND
At A Glance
The Espressivo is a musical amplifier. Looking at specs alone, it’s not going to be able to compete on the same technical level as certain other amplifiers. But, let’s put that aside for a second, and talk about subjective sound impressions. I’ll start by throwing this out there –I do have a slight penchant for cleaner, more analytical sounding gear. It’s one of the reasons why I’ve come to appreciate the ER4 as my primary use IEM. But at the same time, there are occasions where I do feel a tilted signature is worthy and in some instances, even more desirable –hence the TH-900. The Espressivo is one of those instances –a fine example of musicality done right and overall, an impressively exciting sound with great dynamism. Without a doubt the Espressivo needs to be paired correctly. The high output impedance may make for unfavorable interactions, especially with lower impedance headphones. On a related note, noise floor is also rather noticeable with high sensitivity gear.
Soundstage And Imaging
Alright, let’s get this out of the way. The Espressivo does many things right, but soundstage isn’t exactly one of them. With certain tracks, I felt that the width of the soundstage was limited. The Tao Of Love by Vangelis is one such piece. In the past, I have used it as a showcase example of the T1’s ample soundstage and panning capabilities. However, with the Espressivo, I felt that the sound had been clipped on the sides, making for a width that was narrower than expected. Height is okay, but nothing particularly noteworthy. The Espressivo does however offer excellent depth, and this came through with orchestral works. Imaging is similarly good, and there’s a surprising amount of separation and air. This is a strength that works well with the lower frequency performance to provide for a fairly fast and exciting sound.
Bass
The Espressivo has a bass boost –and a very satisfying one at that. It peaks in the subbass region and slopes nicely into the midbass. It’s a fairly clean boost that adds more to the presence than raw quantity of the lower-end. I found that it had a wonderful synergy with the T1, loosening up the occasionally restrained bass while still maintaining a positively responsive sound. The overall result was a much more visceral low-end, one that really made for an involved listening experience. You’ll hear it on tracks like La Cathédrale Engloutie by Debussy (interpreted/played by Jean-Efflam Bavouzet). Certainly, the climax (sonore sans Dureté) was impressive, but it was in fact the opening (peu à peu sortant de la brume) that got my attention. The way the mysterious emergence of the castle from the ocean was captured through the deep bass was very impressive, and it did feel like I was staring into the very depths of the ocean.
Mids
The mids are connected nicely into the overall sound. Perhaps, a little less immediately striking than the bass or highs, but not disjointed or overly recessed by any standard. There is good body behind the mids and its strongest aspect lies in the upper-mids, where I found great energy and richness. A seamless transition into the highs followed. I thoroughly enjoyed listening to Bossa Nova tracks like the Girl From Ipanema, and found that the vocals had a slightly sweet nature while still maintaining a good textural quality.
Treble
The highs are very enjoyable on the Espressivo. It’s fluid and has a very nice sparkle, and is one of the reasons why the amplifier excels in terms of musicality. However, it also has the tendency to get slightly hot, especially on modern and less well-recorded tracks. On Breath Your Name by Sixpence None The Richer, a small amount of sibilance started to come through, and the sonic portrayal got a little intense midway through the piece. At the same time that I want to say that this needs to be toned down a tad, I did find it strangely addictive. User mileage may vary I suppose.
Short Notes On Tube Rolling
So in addition to the 6N1P, I did receive the 6N1P-EW and the 65NP for assessment. I’ll start with the 65NP. I did notice that with the 65NP that the lower and higher frequencies got a slight boost. Generally speaking, there was a little more sibilance on certain tracks, and at the times it did push the Espressivo too far, bringing it into the hotter side of things. I also felt that the sound from the 65NP was detached, especially around midrange, and it just generally wasn’t as good a listen. The 6N1P-EW is an extended life, military grade tube based on the limited background information I was able to find on it. Sonically, it boasted similar characteristics to the stock 6N1P. Perhaps the only notable difference was slightly less bass and a subtle increase in highs. Overall, of the three that I had an opportunity to try, I felt that the stock tubes did the trick and there wasn’t a pressing need to switch them out.
FINAL THOUGHTS
The Espressivo is oodles of fun. It's got an engaging sound signature featuring great dynamism and musicality. The end result is nothing short of a very "big" sound. The build quality is plain excellent, and feels like something fitting for a far more expensive product. Frankly, at a price of 349.00 USD, there's little reason why not to give this amplifier a try, especially if you've suitable high-impedance cans. It's an exciting listen, and when paired with the right cans can really make them sing. If you're in the market for a musical amplifier and have the said higher impedance headphones, I would heartily recommend the Espressivo. It's really good!
