Review: VTL TL 6.5 Tube preamp

Category: Preamps

A REVIEW OF THE VTL TL-6.5 PREAMP in direct comparison with the ARC REF 3 preamp.

adviso : all my comments and assessments are specific to the listening sessions i did in my auditioing sessions i my listening room with the equipment clearly posted here.
[prior to having both preamps in my home at the same time, i listened extensively [5 hours each] to each preamp at the dealer or in my home with the ayre c5xe as source.]

my home audition period : 1 day of listening with each preamp separately, 3 days of listening a/b as shown below.. both preamps were demo models in superb shape and were largely run-in, as were all the cables.

i list nearly my entire audition material and the specific way in which i auditioned the two preamps.
sorry about any typos.

SKIP DOWN TO " OVERALL" et al. at the middle of the text if the audition method + performance listing is of no interest.

important notes: i am not an audiophile. i was a conservatory trained classical musician who had the good fortune of studying with szell's and boulez' concertmaster [cleveland orch, ny phil] etc. the process of moving up from b&w n803's + arcam system to the higher end has been an education. i have no patience with specs and which do-hicky is the most sophisticated etc. for me, the bottom line was what came out the speakers, within budget considerations. my intention was to find the preamp that best suited my needs for transparency, neutrality, naturalness, musicality [a slippery term] and superb bottom to top coherence , provided all that is on the recorded performance! synergy with my existing system played a key role -- synergy issues eliminated other fine preamps from the final round . i had no preference or stake in any preamp from the outset. considerations were budget [$10k], fully balanced, low heat, and reliability of build and mfr. i did not consider looks or remote control layout ease.

it has been pointed out to me by dealers and manufacturers that the specifics of my pass labs amp x350.5 impededence and other aspects of sensitivity may favor the vtl 6.5 over the ref 3 in terms of synergy. this is perhaps true. however, even though the pass x350.5 / ref 3 synergy may not ideal, the ref 3 performed at a level that brought it to the final 2 choices.

system :
wilson w/p 8 , set up by authorized wilson dealer , speaker cable : transparent mm ultra
pass labs amp x350.5
cdp : ayre c5xe [initial auditos only]
esoteric ux-3se
IC's cardas golden ref, transparent mm ultra, analysis plus crystal oval [note 3]

PCs - i used all stock that is supplied with each unit.
pls note - i asked the dealers and mfrs regarding off market power cords. there was consensus that well matched ,excellent power cords will enhance overall performance and may subtly change presentation and offer improved presentation in some aspecs, but by and large no powercord will change the overall character of the component. therefore, shared agreement of the dealers and mfrs was that the stock power cord is a good way to audition the 2 preamps.

power protect: : transparent P8 [not a full range power conditioner]. vtl suggests plugging their preamp direct into the wall.
other: all components on dedicated circuit

home auditon sessions:

>2 x 4 hour listening sessions[a 15 minute break during each 4 hour session] with each preamp alone across a variety of classical music recordings, all redbook cd. no sacd. no vinyl. i took written notes of my observations for overall presentation and specific sections in the music. volume levels adjusted for best comfort with each work. dB levels not compared. these sessions were for overall impressions with some specific sections marked for focused listening later
full range of classical music listening, except no organ music, not large choral works. i rarely listen to these.
most often full movements heard, not 5-10 minute sections for these long listening sessions.

a/b sessions:
dB readigs taken and matched for nearly all movements at this point.
> 3 long program sessions each preamp as follows :
focus: broad range from large orchestral works, concertos, piano alone, opera arias, small ensemble. omissions: no organ music, no large chorus , no chorus/orch.
i listened for 60-90 minutes per session with each preamp,
including 1 full movement or large section of a movement and 4-8 other works per session. notes take.
identical listening session repeated in full with the other preamp. noted taken separately. independent notes then compared. works with interesting differences in various sections marked for short interval a/b comaprison.

> short program comparisons.
3 sessions [ each session : 3 hours, 3 short programs per session ] direct a/b comparisons, switching preamps after each "short program" - identical program played for the a/b:. ie a/b was about every 20-30 minutes per preamp. no switching after after individual movements or sections of movements
focus - chambermusic, piano alone, large scores with large passages of tranparent passages/diverse orchestration. music with dense scoring, sudden dynamic shifts, huge color palettes, extended ranges were handles in the above long program sessions. close a/b was not nec. differences were too obvious.

>>> short programs,the most specific listening sessions :

>. :mahler 4th, entire first movement + first 6 minutes of move 4:
>1 chopin nocture [pollini + 2 movements late schubert piano sonata [brendel]
> beethoven moonlight sonata, entire work [arrau 1966] + 1st movement by 3 other performers [casadesus,brendel,pollini]
> mahler 4th, last 6 minutes, mov 1, 3 different conductors + orchestras, sibelius violin concerto 1st movement, 1 performance [mutter]
> 2-3 songs, schumann lieder, 3 different mezzos/'sopranos [incl von otter, norman ] + misc schubert lieder [wunderlich].
>: beethoven string quartet op 127, mov iii, 2 different string quartet groups [vegh,emerson], schubert late piano trio, 1st move.5 min[beaux arts], brahms clarinet quintet, 1/2 of first mov.
>berlioz sym fantastique [1st move][cleveland] , mozart figaro [1 aria, 2 versions] beethoven pno con 4 [mov 1,fortepiano, levin]
> debussy piano work, brahms cello sonata [1 mov],
> berg chamber concerto , bach BBC #5 1st move [period instrumnts], schubert trout quintet [curzon]

>>> note 3: interconects - switched positions during long sessions. for example, amp/pre with transparent, pre/cdp with ap. the the reverse. then cardas/ap. etc.
transparent not used with with vtl at the rec of vtl as it is a networked cable

other: compared listening with cdp in different inputs in each preamp :
ref 3 : via cdp input and thru monitor mode [subtlely more reveal but with an edge]
vtl : cdp via cd 1 and cd2 [prefered] [different circuit pathways]

both mfrs kindly suggested a small range of possible cable choices. each mentioned that keeping up with the cable industry's zillions of choices and variations is impossible. no doubt different well chosen cables and non-stock power cords may result in presentaion changes that can lessen relative "weaknesses" or play to strengths. i used ICs that were mentioned by the dealers and mfrs involved. this type of audtion is always a compromise in some area, the focus at the end is to be able to hear each preamp on its own merits and a/b the strengths and perceived weaknesses with the least amount of variables. it's a tough nut to crack unless i were to spend quite a bit to rent many or all of the suggested cables etc. .

>>> OVERALL ::

both pramps are very excellent and present almost every aspect that i singled out as below with ease and accomplishment. I would not characterize any individual "fault" or issue that i felt was less than excellent to be a deal breaker. differences many areas are a matter of degree. admittedly, some differences may have gone unnoticed if i did not run my a/b short listening programs [detailed above] . as a result of the a/b comparisons, differences btwn the 2 preamps may have become magnified by the end of the audition as there was an occasional overfocus and some small passages and indeed a few single motif or single note presentations did make impressions that factored into my listening. .kindly remember that most differences are subtle and in fact may lend particular favor to one genre or performance [ie mezzo/piano combo] and not another [large contemporary orchestral music] or to the listener's preferences [in this case, my own.].

>>> soundstage :
both throw excellent soundstages with clear instrumental placement. i found the ref 3 very slightly forward in midrange staging and wider, resulting in a slightly greater sense of air between sections of the orchestra primarily when the melody + harmony are in separate ranges. perhaps because the midrange presents so uniquely engaging. the ref 3 may throw a taller as well, but this was noticed in only a few large orchestral w/p 8 do not throw a tall soundstage in my nearfield listening setup. the vtl 6.5 often threw a more defined instrumental placement,especially at the bttm, but not a larger stage per se. i have concluded that this is due to the overall better bttm end resolution of the vtl 6.5.

>>> hall acoustics [within the recordings auditioned] : i found both preamps to be superb . in large orchestral works, the bottom end breathed a bit more due to clarity with the vtl 6.5, which made me more aware of the hall space, but i cant really say that i rcvd a greater feeling of the presence of the performance space. small ensemble recordings xpressed hall ambience and acoustics equally well with both preamps. without actually being at the recording, it is really impossible to say if there is an over or under emphasis of actual hall acoustics. with both preamps , the spaces and ambient reverb of the hall seemed realistically presented.

>>> orchestral color , timbre wt, and percussion :
both present some instruments with different color nuancesr, but i would venture that both present well within "neutral" context. if we include vibrato as part of color the vtl 6.5 has the edge by its resolution of texture, especially with chamber music. String quartet performances with the VTL 6.5 in particular had greater clarity of ensemble, as i have heard dozens of times live in various concerts in manhattan.
in massed sound of large orchestral works, i liked the almost physicality of the ref 3, though some of the immediate weight as it relates to color was a bit hyper-real at times in the audition process, i associated the ref 3's presentation of the large orchestra as when i played in an orchestra or sat very close, such as the first few rows of the hall. so, within the context of a performer on stage, the color may not be hyper real. but that unique quality of color rarely carries to the 12 row in an orchestra hall. my thoughts may have more to do with microphone positioning for the recording, but i did perceive distinct differences btw the ref 3 and tl 6.5 in massed sound color and timbre.

>>> percussion : both present mid and high pitched percussion instruments well. the vtl 6.5 consistently resolves better than the ref 3 in the bass range, so bass drum and timpani had more clarity and nuance. drum rolls and quick rhythmic figures had more clarity as did transients and decays. sleigh bells [mahler 4th] had a more specific twang and color to them with the vtl 6.5 to the point that if i were a percussionist, i would probably be able to tell you the metal by the characteristic of the sound. with the ref 3, sleigh bells sounded like sleigh bells, but not so particularized. with both, i felt the physicality and metallic properties of triangle, chimes, etc. excellent. overall, the lack of detail and nuance at the low end with the ref 3 was an issue for me. chimes had greater palpability and decay, even nuance [if this is possible with chimes] with the vtl 6.5[berlioz sym fantastique]

>>> full range coherency, scope of sound in various ranges:
at soft to medium volume levels, both preamps presented excellent coherency overall with ensembles of different instruments. extension of range was similar and superb. in large orchestral scores, the ref 3 presents a glorious midrange and very liquid highs. very engaging, but perhaps not fully realistic as the bottom seems under presented [or is it that the mid range is overpresented or colored slightly?] perhaps the vtl presents a more realistic coherency overall because it does not play favorites with one range more engaging than another, as i feel the ref 3 does by nature of the attention grabbing midrange. at loud levels, coherency remained fully intact with the vtl , especially in long crescendo passages. the ref 3 did not handle large orchestral crescendos as successfully, especially on massed sound [bruckner 5th]. as such, i felt the vtl 6.5 presented a more organic total range coherency than the ref 3.

>>> solo piano / piano alone : vtl presents greater cohesiveness of recordings with piano alone . the ref 3 presented some character and tone color changes as the compositions changes ranges that should not have been noticed on the modern piano. for example, in scale passages or continuous movement up / down the keyboard [chopin, schubert late sonatas] mid range color and timbre was a bit more up front and the bottom end seemed veiled at times with the ref 3. kindly assume i understand the differences of a properly voiced modern piano and that chord progressions in C major do not have the same character as chord progressions in A flat major.

>>> handling of dense passages : [excluding the piano ]
in upper midrange and high end, both are excellent. the vtl 6.5 is exceptionally clear at the bottom and lower midrange, the ref 3 had occasional problems here. textures and detail were slightly muffled . the sound with the ref 3 is full bodied in the lowest range , but lacks some of the clarity i recall timpanists [and conductors] obsessing over during rehearsals. with the ref 3, quick articulations can be smeared mostly at the bottom end, but also in midrange passages in chamber ensemble works as moderate volume. the rite of spring, 2nd part, had superior articulation at the bottom with the vtl 6.5. with full overtone dimension.

>>> handling of sparsely orchestrated passages in large orchestral works; chamber ensembles.
bothpremaps are outstanding... and different.

the ref 3 engaged me with the performance immediately, especially when there are long slow melodies in the mid range thru c2. my initial impression of the vtl 6.5 was that it presents small ensembles in a slightly laid back fashion, but as i acclimated to myself as audience member with an aural perspective akin to the 12 row seat in the performance space [rather than the feeling of several rows closer with the ref 3 presentation] i was drawn more easily into the composition as the sum of its parts, with a greater awareness of inner detail overall. with the ref 3, i felt my ear was drawn and held more to the main material of the music, always gloriously presented in small ensemble works. but i felt nudged or guided nevertheless! . in some ways, the ref 3 had me listening with my eyes as if in attendance at a live performance. ie we search for and watch the performer playing the melody. this was an issue for me and not a subtle one in chamber music. i love to hear the richness of the inner voice detail that excellent musicians bring to passages and indeed the whole of the work. the vtl 6.5 consistently gave me an unencumbered opportunity to explore 2ndary motifs and background textures while presenting a comprehensive perspective of the unfolding performance. There was a more organic cohesiveness that i have come to prize highly with small ensembles that have that magical synergy, as if everyone is on the same wavelength.

>>> piano alone - presentation -
both present the piano excellently and somewhat differently. the ref 3 excels in midrange beauty. i was often startled in terms of immediate emotional impact. i was always quickly engaged with the presence of piano sound. easy to fall in love with this type of presentation. this is, to my ears, a less accurate presentation of a piano live in my experience. as an audience member, i would characterize the immediacy of piano sound with the ref 3 as sitting fairly close to the piano, around 6th row if not at the keyboard itself , as compared to the vtl 6.5's perspective of 12th row. and yet, surprisingly with the ref 3, i had resolution issues with the ref 3 in the short program a/b . i found the bottom end of the piano somewhat diffuse with the ref 3. sudden dynamic changes were less nuance in attack and decay..sfortzandos and subito fortes [beethoven ,moonlight sonata, 3rd movement] were smeared especially in the stacked cumulative chord passage or the chords encompassing a wide spread. sections of pictures at an exhibition, piano version, failed to express percussive bite at the bottom with the ref 3 , gruffness was veiled at the bottom. in comparison, the aggressive sections of pictures were wonderfully textured with the vtl 6.5 as was decay. although i found that the vlt 6.5 presents the piano farther back [not distant] than the ref 3, the richness of overtones as well as the fleeting details are revealed to a greater extent with the vtl. i wonder if the greater synergy of the vtl with my pass amp was a large factor here because the ref 3 underperformed too greatly in this area. .

i listen to a great deal of chamber music with piano [string/piano sonatas, piano trios etc] as well as piano alone, so this exceptionally hard-to-reproduce performance instrument, the "modern" piano, became the make or break test of the preamp audition for my system. largely, i found the vtl resolves bass and inner detail across the board more fully than the ref 3. other: with the vtl 6.5, i heard more frequently the hushed twang of strings when dampers drop and very quiet pedal action more distinctly -even when very much in the "background" of the recording. in some recordings, the faint damper action heard with the vtl was unheard with the ref 3. with the vtl, ornamentation [chopin] and incisive repeated note passages, most often in the bass [beethoven, mozart] had superior rhythmic clarity with the vtl. this specific clarity, i would argue,is the foundation on which classical through mid romantic works require [ever listen the intrinsic capabilities of the instrument for which these composers wrote, the fortepiano?]. additionally, overtones are more pronounced with the vtl 6.5, enriching the total soundscape of the piano, recalling a live recital up close, but i never felt the overtones were too ripe or over-boosted. hearing full decay in not only quiet passages but even in pedal points in loud passages was very satisfying with the vtl. it was just less realized in many passages with the ref 3. overall, the vtl 6.5 expressed more qualities unique to each pianist's interpretation and artistry via a more organic and accomplished presentation of details, texture, and nuance captured in the recording of the performance. ultimately, a wonderful musical performance is the responsibility of the performer, not the preamp. how substantial a wonderful performance it is... well, this is where the preamp must be the critical facilitator.

>>> unique pluses :
ref 3 - seductive midrange and above, liquid highs. large sense of immediacy almost instantly with small ensemble works. if you listen more for that up close and personal sweep and engaging midrange melody you will rcv instant gratification with the ref 3, especially with baroque music,as well as opera arias. intimate vocal passages can be utterly captivating. the overall sound quality of mid brass, winds, and the piano is wonderful.

vtl - superb coherent presentation, no overemphasis or highlighting of any range, beautiful clarity and command of the bottom end, wonderful inner detail transparency,fast presentation of transients, handles quick dynamic changes and loud passages without loss of resolution. however, "analytical" never came to mind, more of a preference for a balanced fullness than a lean voluptuousness. the preamp was just exceptionally revealing of nuance. i got a greater sense of the scope and architecture of large orchestral scores as well as more ambitious ensemble and piano alone works with the vlt 6.5. [i consider the last movement of the beethoven moonlight sonata one of the early examples of ambitious piano writing.] diction in lieder was clear and more subtly inflected.

>>> unique minuses

ref 3 : issues with clarity in the bottom end. slight congestion in the mid and upper bass in thick scoring as well as less coherency when handling crescendos to sustained fortes primarily in large orchestral works but also some loud passages of piano works. subtle differences in timbre not as distinguished as the vtl, particularly in percussion. with the ref 3, i found less inner resolution though this was confined mostlyto the bottom and mid range. in some respects, the strengths of the ref 3's emotional engagement of the midrange works against the overall architecture of a composition in a very subtle way. ie when i listen to chamber music and colorful orchestral scores [mahler 4th ], during a wind or string solo passage, it is almost as if the orchesta at large falls into shadow.

vtl 6.5 : occassional distance in terms of my engagement with some performances, especially very slow tempo piano music with a strong midrange focus when a/b'd with the ref 3. the vtl's presentation , favoring what i associate somewhat more "unbiased" approach, will not help lackluster interpretatios. performances short on nuance will be more obviously so when compared with richer performances. [see some of my short programs where i listened to several performers in the same work]

>>> overall personal opinion : my grain of salt .

the vtl tl 6.5 approches its neutral presentation from a patrician perspective. i understand its attainment of fullness from a balanced, holistic context

the arc ref 3 approaches its neutral presentation from an earthy perspective. i understand its attainment of fullness from a more voluptuous, emotional context.

of course, this distillation of character between these two pramps is folly. but fun.

i would be satisfied with either preamp. more so if i never heard them side by side for several days in my system.perhaps more so if i had a different amp for the ref 3.

thanks for your patience.
comments invited. frakness is appreciated, within the context of constructive and well mannered dialog.

oh, i bought a vtl 6.5 if it wasn't obvious.

when it arrives, i will run it in fully and give myself several months to enjoy music ... before i seriously consider ICs and possibly a PC or two. suggestions gladly accepted. as to changing other components in the system: not at this time. ask me again in 5 years. thank you.

Associated gear
see the small text in my review

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review focuses on the vtl 6.5 in direct comparison to the audio research ref 3. both auditioned i my system during the same time frame
Ag insider logo xs@2xsoundisntmusic
Thanks for taking the time to write up such a concise review.

Was the VTL 6.5 the MkII or Signature version or the original version?
Soundisntmusic: Now say you were a Jazz/Vocal fan... what would have been your choice?

Based on your detailed analysis of the characteristics, I would think you might have gone down the REF3 path in that case - but I won't put words in your mouth.

thank you all for your kind remarks of my review.
here are some specific follow-up to those how posted suggestions, questions, and other points.

guidocorona - thanks for your comments and past dialog. the ref 3 i used was the latest prdouction model with all up-to-date caps, etc. it had over 500 hours on it, ie fully run in. doubtful there were any tube problems as this unit is regularly used by the dealer with wilson alex2's.if they found a problem after i returned the unit [ie a faulty or failing tube] they would have called me to do a re-audition.the dealer, stereo design,is top notch.
i studied with rafael druian,who was concertmaster of cleveland under szell and under boulez in nyc.[also dorati in minneapolis].

pscialli - thanks for the PC rec. i have also been advised that the nordost valhalla PC works well with the vtl, among others.

cytocycle - the tp 6.5 has only one version. i used a run in production model. i beleive there is a recent magazine review where the reviewer stated he 1stly had a pre-produciton model with dif tubes, then a production model.
- i will speak to vtl directly regarding the suggestion you make regarding tube changes. thanks.

hatari - i regret that i listen infrequently to jazz/vocals, though i do have a good deal of cole porter with many original performers, some armstrong, ella, etc. but this is not my focus. i really cant say if i would choose differently, especially if the piano was a prominent part of ensemble jazz across the board. on the other hand, i wonder if the way one listens to jazz vs classical music as a genre is fundamentally different and therefore may alter what one seeks within the context of listening [and repeat listenings of the same performance?] . by this, i mean that, forgive my naivete here, but with jazz, which is less scripted compositionally [or rather more fully embracing to performer/ensemble variations in terms of harmony, details, rhythm and orchestration], one most frequetly listens to these performance variations as the very core of personal/artist jazz interpretation, especially in terms of ensemble and backup material ad libs. With classical music, where performers are more focused on a relatively slavish subscription to the written score [baroque music aside, which by the way is perhaps the most closely similar to small ensemble jazz music in terms of freedom of rhythmic and harmonic interpretation [figured bass] as well as melody transformation via ornamentaion etc] the window for "interpretaion" of a work as a whole is significantly smaller in classical musicthan in jazz. not to mention generations and centuries of performance traditions to consider. therefore, i would suggest that in classical music, the inner detail nuance plays a greater role in the overall scope of what we define as "interpretation". i am not suggestiong that there is less finesse in the performance quality of a jazz combo's "back-up" performers, but rather that in jazz, they are not under the microscope as greatly as the viola section would be in mahler, for example . so the possible benefits of the vtl 6.5 preamps strengths in inner detail resolution may be less appreciated than the ref 3's ability to present that mid-range immediacy. if i was predisposed to listen to a huge selection of music over a few weeks at a time without multiple listening to the same work, the ref 3's strength may be more appealing. but i tend to listen to a handful of works several times [and the same works by different performers] over a few weeks time. perhaps my collection of classical music would reveal this. though it is wide in diversity , i can admit to 6 full set recordings of the 18 beethoven string quartets, 10 recordings of the berg violin concerto [differet performers] and probably 3-4 different recordings of most of the major piano sonatas. not to mention, sometimes i listen with the scores in hand. though not a slave to the notes. LOL.
Thank you Marc! Have you already tried the Valhalla. It tends to create a very slender midrange which I do not find to be congruent with unamplified bowed strings.
Thanks for that. Did you consider the VTL amps to complement the 6.5s? The MB 185s and 450s are something special too.

Enjoy and thanks for the well thought out details.