Review: Linear Tube Audio Z10 Integrated Amplifier


Review: Linear Tube Audio Z10 Integrated Amplifier

 

Disclaimer: I : am not an audio professional, am not in the industry, have no affiliation whatsoever with any audio manufacturer nor retailer/reseller. I pay for my gear like any other hobbyist.  I have received no consideration or discounts for the opinion that follows.  With this caveat to please the bloodthirsty, on to the topic of this post.

 

I have enjoyed a lot of gear over the years, some humble, some not so humble. I enjoy hifi equipment and I appreciate the craftspeople who have made it possible through the years for me to enjoy my music. I have enjoyed separates and integrateds, each for different reasons. I have owned Shindo, Audio Research, Leben, Line Magnetic, Naim, Nagra, McIntosh, VAC, Cary, Pass Labs, Primaluna….the list goes on and on. I presently have 2 Leben and 2 Line Magnetic integrated amplifiers and my speakers are Devore Fidelity O/96, IC and speaker cable is all Auditorium 23, power is Running Springs Jaco, power cabling is Audio Archon.  Dac is Lampizator Golden Atlantic fed by a Roon Nucleus Plus server with 4tb internal ssd drive, streaming is via an Auralic G1 through a Curious usb cable to the Lampizator.

 

I have been reading with great interest about Linear Tube Audio for a couple of years now and watching their product line evolve.  I have been more than mildly interested in the ZOTL technology as one example of what appears to be a material breakthrough in vacuum tube amplification. I wanted to try something to get a taste of this technology but I really didn’t want to invest what Mr. Berning gets for his gear at retail…so I reached out to LTA.  I couldn’t decide between separates (Zotl 10 (el84), Zotl 40 (el34) or the new Ultralinear amp) because I was looking for sound quality, not power output. I settled on the new Z10 el84 integrated.  Mark with LTA was so very patient with me as I wrestled with the choices…more than I would have been had the roles been reversed!

 

Well, so how does it sound? It’s a bit confounding cold out of the box with zero hours. It sounded great but I was coming straight from a Leben CS300x with NOS Mullards. The Leben sounds “tubey” with a glorious midrange and at the extreme lower frequencies, it can be a bit “loose” on full range speakers. The Leben mids are sublime, slightly rich and euphonic. The highs, also quite rich and airy while enjoying a fine sense of space and presence. The Leben is an amp I don’t think I will ever sell even though I’ve had 5 or 6 of these over the years, this particular Leben is a perfect CS300x Limited which came with the old stock Mullards and JAN 5751’s.  The Linear Tube Audio Z10 Integrated evolved materially as it began to accumulate some hours. First of all, I can’t believe its only rated at 10 wpc into 8 ohms. It sounds FAR, FAR more powerful and I haven’t pushed it yet.  Second of all, it is dead quiet.  Like “check to see if it is on” dead quiet…”ear to the tweeter on my 96db speakers and can’t hear anything” quiet.  

 

I recently had a Pass Labs XA25 amp (along with an Audio Research Reference 75se) in my system driven by an Audio Research Reference 5se preamp. Both the XA25 and the Ref 75se are fantastic amps. Between these two amps, the Ref 75se was more of everything than the XA25…texture, layering, attack, decay, tone. The leading edge of notes of the XA25, however, is terrific and it is a great amp and a fine value at its price. The Z10 Integrated from LTA gives up nothing to the ARC, the Pass or the Leben and exceeds each in several key areas. It has slightly less “tubeyness” than the Leben without losing the magic.  It has much more “tubeyness” than the ARC without losing the accuracy. It possesses a richness of tone that exceeds what the Pass XA25 does so well but I believe the Z10 does so considerably better. It has leading edge crispness and dynamics that one would typically associate with the best solid state. The top end of the Z10 remains smooth and composed while the air and tone of the top end is there in spades. Where the Z10 has blown me away is with the bass. It hits like a hammer when its on the recording. Play Copland’s Fanfare for the Common Man and hold on for dear life. No hyperbole, its real. The Z10 possesses dynamic, tuneful and well defined bass that is both rich and authoritative. I have maybe 90-100 hours or so on the Z10 and the folks at LTA state that 7 full days (168 hours) are necessary for the Mundorf caps to fully settle in. The Z10 is rich and dynamic and the soundstage width, height and depth are all first rate. The Z10 accomplishes this without drama or fanfare, just amazing sound.  A quick commentary on the casework by Fern & Roby. First rate fit, finish and aesthetics. Everyone will be impressed when opening the box and placing it in your rack. The brass buttons really accent and enhance the overall look and they are touch sensitive buttons, not depress and click type buttons. Very cool. A nice departure from brushed aluminum silver boxes with silver or black buttons vs brushed aluminum black boxes with silver or black buttons.

 

There are three things I might alter if it were in my power to do so. First, the shipping box/materials could be enhanced as it’s a single box with foam inserts. It worked wonderfully, the Z10 weighs far less than 20 pounds so there is really no issue but there is something nice and reassuring about the double/triple boxes we all see with purposeful foam-cell cutouts. Maybe its just that I am used to the kind of boxes/materials required to safely ship these 75-100 pound amplifiers around that its probably just me.  Second, a minor nit but even though I haven’t opened the casework to see inside, I see the small hex head screws like those used by Audio Note. They work better than flat or phillips head screws and there are only a few to remove compared to an Audio Note case but my dream would be some quasi-recessed thumb screws for those who enjoy a little tube rolling. No company to my knowledge is doing this anyway so no big deal…the lawyers would probably cry foul anyway.  My final wish is very minor. LTA has ingeniously utilized an Apple remote. It’s a fine small aluminum remote, well made, a good size and inexpensive/easy to replace in the future should the need arise. Its available everywhere and a brilliant engineering solution by LTA.  In the future though, I would LOVE to have the option of a Fern and Roby milled brass remote (or maybe engineer something that the Apple remote could slide into) that would match the front panel buttons of the Z10. The buttons are not a polished, clear coated brass like you might see used for handrails at the airport Sheraton, they are a nicely executed matte finish brass. It would really be a nice look but hey, I don’t know how much extra I would pay for these items but I would be willing to pay something extra given the opportunity.

 

On the topic of price/cost. I chose the Z10 for a turnkey on-ramp to see what all the fuss was about with LTA and the Zotl technology.  They offer a generous return policy so if you don’t like it for any reason, it can be returned for refund. The price as of this writing is just under $5,000 depending if you get the phono stage or not. I did not get the phono stage so no opinion on its performance.  It has a fantastic, I mean a really fantastic high/low power headphone stage, a tape monitor and sufficient inputs, with one balanced input to accompany the single ended inputs. I would put the Z10 Integrated up against anything I’ve ever heard with a high degree of confidence. If you can live with under 20wpc, you owe it to yourself to experience this amp.  Notice that I say 20wpc rather than its 8 ohm stated power rating of 10wpc because it just “feels” so much more powerful.  I once had a Nagra 300b integrated amp and I would take this LTA Z10 every day over the Nagra…. and I liked the Nagra! The Z10 is far and away more rich, more musical and it feels far more powerful to boot!  I haven’t listened to that many SET amps but this amp evokes that kind of purity of tone to my mind’s eye.

 

In closing, the Linear Tube Audio Z10 Integrated amplifier is easy to live with, it is easy to operate, it is easy to place and it puts off surprisingly little heat.  The sound can best be described as it brings the best of tubes to the table and injects those few areas where solid state outperforms tubes (very few in my opinion LOL) in the areas of bass, leading edge transients and image specificity. The headphone section is exceptional and the quality of the build is first rate. This thing is seriously underpriced…if this amp listed at $9,000 I would think it was a fair price for what you are getting. I’ll be keeping it, even though I have a lot of time remaining on the clock to return it.  I paid full retail, much to my chagrin because I hate paying full price for anything.  I will always have a couple of other amps around like the Leben or the Line Magnetic. Sometimes I just want to listen to something more euphonic, like a good el34 based amp in triode mode with a quad of Mullard xf1’s installed. Like when Muddy Waters sings of the virtues of a “Big Legged Woman”. I have also been known to eat butter, bread and a fatty prime steak to excess on occasion as well!  I was completely surprised by the sound of the Z10, which is very difficult to describe.  The Linear Tube Audio Z10 Integrated Amplifier checks all the boxes for what and how I like to listen to music. Whatever you throw at it be it jazz, classic rock, classical, intimate vocal performances….it excelled at each!  That's kind of the point though isn't it? Hifi gear should play what's on the recording very well in a very pleasing way.  I’ve never posted a review like this, LTA had no idea I was going to do it, I haven’t communicated with them since the day the amp arrived nor should it carry any weight with anyone reading this that they should or shouldn't like it.  These are just my observations.  If you have reasonably (not ultra sensitive, just reasonable) sensitive speakers or your listening tastes don’t often find you venturing into Rush 2112 at 110db volumes played through 82db speakers, this may be an amplifier you should consider.  I wouldn’t hesitate to pair this amp with Devores, Harbeth 30.2’s, etc, etc. YMMV and Peace.


ghasley
Hi Keith. I'm going on aural memory and since we know one another, I hope you will cut me a break. LOL.

I found the Nagra 300i integrated amplifier to have less warmth and a smaller soundstage/presentation than even its stable mate, the Nagra 300b standalone amplifier. That was years ago on different speakers. If I were listening back to back between the Nagra 300b amp and the Ref75se, I wouldn't hesitate in betting my house that I would prefer the warmth, texture and presentation of the Ref75se every time.

You are aware that I loved my ARC Ref75se/Ref5se combination with my Devore O96 speakers. The Z10 LTA is less dense than the ARC combo but was more agile and fast sounding. Very dynamic for its stated power but I bet I never used 2 or 3 watts. It is a remarkable sounding little amplifier, extended frequencies on both ends of the sonic spectrum.

I believe the Nagra 300i was developed at a time in Nagra's corporate structure at a time where they may have been attempting to take the 300b tube and make it sound more "accurate" and "linear". Well, it sounded to me after a while like really good solid state then. Why did I buy it? I ordered the integrated after hearing the standalone amp driven by a Nagra tube preamp which may have explained why it had just enough warmth to cause me to pull the trigger back then. I believe Nagra made a mistake fitting the integrated version with the solid state pre section. As you know, among the several amps that I have presently, I switch between a Leben cs600 and a Nagra Classic integrated. I would wager that my Classic Integrated has a great deal more warmth than the 300i.

Anyway, good luck and best wishes Keith.
I am looking for anyone who is using this integrated with the phono stage.   How good is the MC/MM section?  Is it good or great?  
I just got the Z10 last night after reading this and many other reviews. All I can say this early on is that you are so spot on with the sound description. It’s so much more immediate, clear, and defined than anything I’ve had before. Just radically different in terms of space perception, definition, and illustration compared to my Primaluna. Bass is deeper and stronger, soundstage is wider and deeper, and it’s so dead freaking quiet you can hear everything. Didn’t realize how much transformer noise the Primaluna has by comparison. 
It’s early still so I’m hoping my only wish will come true and that is that the high end will smooth out. I expect it will but it’s only got 5-6 hours on it. Everything else is blowing my mind. The headphone amp gives the same qualities just with even more immediacy and crazy good bass for my HD650s. 
Rick, give some break-in time. The amazement continues.

Reviving this thread to hear if anyone can chime in with what they think of the Z10 phono stage. I just ordered one from LTA, but it will take up to three weeks to receive it. I’ve been using a Tavish phono pre with a MicroZOTL2 into a pair of Zu Dirty Weekend mkii speakers. I absolutely loved the sound. But LTA had a Labor Day weekend bundle sale, and, well, it was enough of a discount for me to pull the trigger on the Z10. I’m in the mood to cut the clutter and power cord tangles and just go with one box to rule them all. Still curious about how the phone amp sounds, tho....