I originally intended for this review of the Linear Tube Audio Z10 integrated amplifier to be sort of a mini-review in conjunction with the Fern & Roby Raven loudspeakers since I was scheduled to only have it on hand for a few short weeks. Since my time with this amazing $4950 integrated amp was extended, and because I was so impressed with it, I’m giving it a more thorough evaluation.
Christopher Hildebrand of Fern & Roby wanted me to try the Z10 Integrated with the Ravens for an obvious reason—LTA is his preferred amplifier manufacturer for his loudspeakers. It’s what he recommends to his clients, and it’s what he sells when he’s assembling a complete system. It’s also what he uses at home.
My own experience with Maryland-based LTA has been extremely promising. In my “Because I Said So” column in the Summer Issue of The Occasional, I talk about all of the new brands on the high-end audio horizon that have captured my heart since I came aboard the magazine, and no other manufacturer fits this description better than Linear Tube Audio. Over the last year, I’ve heard LTA mated primarily with two speaker manufacturers—Fern & Roby and Spatial Audio—and while I was at first dismissive at the simple black-box aesthetics of LTA, I changed my mind as soon as I had a serious listen.
The Linear Tube Audio Z10 continues to have a low-key approach to its design, although Christopher Hildebrand has redesigned the casework of these amps so that they are beefier and more attractive. The main draw of these amps are David Berning’s classis ZOTL (Zero Output Transformer-less) circuit, which tends to be magical when it comes to delivering a pure, musical sound.
The Z10 Integrated has just 12 watts per channel powered by EL84 tubes. (The entire tube complement is premium NOS, with 4 12AT7s, 2 12AU7s in addition to the 4 output tubes.) It’s basically the ZOTL10 power amplifier, a Berning preamplifer and LTA’s impressive digital control system in one box. A phono stage is available as a $500 option—mine came without. It also has a very nice headphone amplifier with separate jacks for high and low gain, a home theater function and a very impressive set of programmable functions. The remote control is small and sleek, and paired with Apple TV remote functions.
Want to hear the feature I loved the most? Forgive me if you’ve seen this before—I haven’t, but the Z10 Integrated memorizes the volume levels of all five inputs (one XLR, and four RCA) so that you won’t have one of those whoa! moments when you switch sources, forcing you to scramble for the volume control. I like that a lot.
When I first put the Fern & Roby Ravens into the system, I used the Luxman LX-380 integrated amplifier that I reviewed so favorably in the Summer Issue of The Occasional. The sound was relaxed, smooth and with an enormous soundstage that I really enjoyed. I was happy until Christopher arranged for the LTA to arrive at my door.
With the Z10 taking the place of the Luxman, the sound seemed to pop. The Z10 Integrated sounded more immediate, more forward and more dynamic, with more inner detail than before. This isn’t dissing the LX-380 at any level since that amp, with only a few more watts at its disposal, excelled more consistently with a wide range of speakers. The Luxman sounded great with my trio of 2-way reference monitors—the Brigadier Audio BA-2s, the Trenner & Friedl ARTs and the Axis Voicebox—and the Z10 Integrated wasn’t that impressed with any one of those with their 84-86 dB efficiency ratings, but each combination made music as long as I kept the listening levels low.
But with the Ravens, the Linear Tube Audio Z10 Integrated provided a stunning and realistic sound that gave me goosebumps. Now I know why Christopher loves these amps with LTA—it’s clear that they were voiced to sound absolutely incredible with each other.
I spent many memorable hours with the LTA/Fern & Roby combination, along with the Technics SL-1200G turntable, the ZYX Bloom 3 cartridge, a couple of SUTs from Bob’s Devices and Furutech cabling throughout. With all of these components in place, I heard a sound that was still incredibly relaxed and musical, with one of those soundstages that clearly define the room boundaries of the recording venue in a vivid manner.
In my review of the Fern & Roby Ravens, I geeked out on a Lyn Stanley’s current recordings that focus around her tribute to Julie London. (I know, I know, I’ve mentioned these LPs in my last three hardware reviews because they’re such a great evaluation tool. I’ll try to tone it down in the future.) On the direct-to-disc recording of London with a Twist: Live at Bernie’s, I could clearly feel the alive-and-breathing session and how the whole album was recorded in one take with all of the page turning and musician shuffling that occurs between the songs. The Z10 Integrated was able to keep those peripheral sounds clear and spatially correct without distracting from the main performances, adding a realism that gave me a perpetual case of the goosebumps from beginning to end.
On other stellar recordings on LP, such as MA Recordings’ 45rpm Sera una noche, sold to me at a high-end audio show by Todd Garfinkle himself, I heard an earthy presence that could only be produced by Argentine musicians playing folk songs with pure, unfettered passion. I consistently detected a warmth that comes only from the physical bodies of the instruments and their contact with the physical bodies of those splendid, dedicated performers.
Bass was extremely satisfying, even with a 12 watt per channel tube amplifier at the wheel. Low frequencies were textured and taut, with all of those resonances that offer cues that the recording was captured in the most natural way, with almost no bothersome processing in the studio. Remember in the olden days of high-end audio when we used to talk about veils being perpetually lifted from the signal? The Linear Tube Audio Z10 Integrated constantly made me feel like I was so much closer to the performers—ah, another audiophile cliché—but in a very specific way, a way that prompted goosebumps. I wasn’t just hearing these performers in the room, I was feeling their presence, feeling the air move as they walked past.
The only caveat for the Z10 Integrated is that relatively low power rating, which of course means that your speaker must be a carefully selected partner in this absolute goodness—and of course I know the perfect speaker match. But I did try the Z10 Integrated with another relatively efficient speaker, the Opera Primas (91 dB, 8 ohms), and I have to admit that I’ve never heard the Primas sound more warm, open and convincing.
Linear Tube Audio informed me, however, that “LTA amplifier owners have found great enjoyment using their amps with a variety of speakers outside of the recommended ranges.” They stress that those recommendations are guidelines, not rules: critical listening environments, 90db sensitivity and above; smaller rooms/lower volume levels/non-critical listening, 88db sensitivity and above. My listening room is medium-sized, and I’m well past the age where I have to crank. That’s why I never felt that the Z10 Integrated had “only” 12 watts.
Think about it this way. The Ravens and the Linear Tube Audio Z10 Integrated are an amp-speaker combo that only costs $15K complete, and yet you’ll be treated to a sound that can be at least as powerful and musical as huge speakers with a giant amp with ten times the power or more, and at several times the cost. There’s a delicacy and authenticity to the Z10 Integrated that can’t be ignored. You’ve probably heard reviewers say how sorry they are to see certain components leave, but I feel like I have a hole in my heart where this equipment once made its home for a few brief and worthwhile months.