TL6.5 Series II Signature Preamplifier

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More than seven years after introducing the TL6.5 Signature Preamplifier to wide acclaim, VTL presents a significantly revised version, the TL6.5 Series II. The new model incorporates numerous circuit improvements while retaining the best elements of the TL6.5 platform. The proven strengths of the original system design include a single chassis architecture, a fully balanced differential design, a hybrid circuit that combines tubes in the gain stage for voltage linearity, with a FET buffer for greater current capacity, a high resolution volume control with high overload capability, and precision-regulated power supplies. The highly-regarded user interface of the TL6.5 platform is renowned for its intuitive functionality and ease of use, with full-function remote control, and a fully bi-directional RS-232 control interface for increased compatibility with modern home theater systems.

The TL-6.5 Series II incorporates most of the advanced technology found in VTL’s flagship preamplifier, the TL-7.5 Series III, for a dramatically higher level of performance compared to the original design. The new version features an extensively revised power supply based on current-sourced shunt regulator technology that minimizes impact on the audio signal. Far more precise power regulation yields dramatically improved rejection of noise and AC fluctuation.

The completely redesigned high current gain stage utilizes newly available FET technology developed for green technologies such as solar panels and electric cars that require a normally-on state. Unlike MOSFETs that need to be biased on, normally-on devices operate more like vacuum tubes in the audio output stage, with simpler circuits that continuously conduct current, resulting in a more tube-like sound. The high-current gain stage is shock-mounted like the TL-7.5, and has been further optimized for linearity, with zero global negative feedback.

Also included in the upgrade are re-voiced audiophile grade capacitors and additional bypassing.

Enhancements to the Series II result in an overall more tube-like sonic character, with more defined images in the listening space, a higher level of inner detail, and a dramatically improved mid-bass and midrange. The TL6.5 Series II is an exceptional match with any of VTL’s other Signature products.

TL6.5 Remote Control
TL-6.5 II back view
TL-6.5 II top view

Functionality features

Audio circuit features

  • Fully balanced differential circuit with balanced in and out, and mirror-image layout
  • Simple 2-stage circuit topology with differential gain stage and output buffers for musical purity and integrity
  • Ultra low impedance output stage to drive any length of cable and any power amplifier/paralleled amplifier/subwoofer load
  • 20 microfarad output capacitors for powerful bass control
  • Tube complement: 2 x 12AU7/ECC82 tubes
  • Gain switching between normal gain and low gain with 6dB gain reduction
  • Single fully balanced differential 95-step 70dB discrete resistor relay attenuator for all attenuation functions

Control and power supply features

  • Precision regulation
  • Ramped B+ filament soft-start power up for extended tube life
  • Huge energy storage power supply for elimination of AC fluctuation and noise rejection
  • Low noise processor control design for all functions

User interface features

  • Processor loop – any of 8 inputs can be assigned as fixed unity gain pass through
  • Tape monitor function for both tape loops
  • 2 separately programmable trigger outputs
  • Bi-directional RS-232 interface
  • Programmable input offsets
  • Rigid Combination steel and non-magnetic chassis and machined aluminum remote wand

Additional features

  • New FET device output stage for more tube-like sound and simpler bias circuit
  • Improved current source for improved musicality and better single-ended operation
  • Zero Global NFB for vastly improved faster dynamic and tonal resolution, and unconditionally stable circuit, without any phase shift.
  • All audiophile grade capacitors in signal path with bypass system for improved HF resolution
  • Vastly improved lower impact and greater precision-regulated current-sourced shunt power supply
  • Teflon power supply bypass caps for improved top end
  • Microphonically damped tube gain stage for greater vibration noise elimination

Documentation

pdficon_smallTL6.5 Data Sheet

Technical Specifications

Vacuum Tube Complement 2 x 12AU7
Inputs 3 pairs balanced/XLR or RCA single-ended, 5 pairs single-ended/RCA
Outputs 1 pair balanced out, 2 pairs single-ended RCA out, 2 pairs single-ended RCA buffered Tape Out
Remote control functions Power, Source Select, Volume up/down, Mute, Fade, Balance Control, Phase Reverse
Gain NORM: 14 dB single ended, 19.2 dB balanced
LOW: 7 dB single ended, 13 dB balanced
Output impedance 50Ω (500Ω @ 20Hz)
Input impedance Balanced: 112kΩ (36kΩ min)
Single ended: 54kΩ (18kΩ min)
Frequency Response +0, -o.3 dB 10Hz – 200kHz, into 5kΩ 1000pF load
Maximum Output Voltage <1% THD 13V 10Hz – 200kHz into >5kΩ load
Channel separation >100dB @ 1kHz (>80dB @ 20kHz)
Power consumption 150W
Dimensions W x D x H 17.5 x 17.5 x 6 inches (44.5 x 44.5 x 15.3 cm)
Weight 46lbs (20.86Kg) unpacked, 57lbs (25.85Kg) fully packed

Hi-Fi+ Editor’s Choice 2020

VTL TL6.5 Series II Signature line stage and S-200 Signature power Amplifier

HiFi+ Editors Choice 2020

“It (TL6.5 II) has added serious low-frequency extension and grip to the mix, moving it far closer to the flagship 7.5 in overall performance.”

“The S-200’s neat trick is to deliver a realistic impression of weight and scale, pitch and extension.”

Read the full article here…

- VTL TL-65 Series II Signature line-stage and S-200 Signature power amplifier Reviewed in Issue 179

TL6.5 Series II and S-200 | HiFi+ (UK)

“The VTLs performance matches what is an expressive and dynamic tour de force. Repin and Argerich … their playing is at once intimately conjoined and dramatically bold. The VTLs paint a richly vivid musical picture, full of body and presence, light and shade. The instruments are held separate in space, with a beautifully natural sense of differential height and scale, surrounded by a convincing acoustic space. The connection between the musicians is as tangible and articulate as the interlocking phrases of the piece, sure sign that the amps have got the timing spot on.”

“Spending time with these VTL amplifiers, it is easy to understand how and why the company has quietly but confidently established itself as the go-to option for versatile, high-powered tube amps. The TL-6.5 and S-200 don’t just tick the boxes – they own this turf!”

Read the full review here…

- Roy Gregory, “VTL TL-6.5 Series II Signature line-stage and S-200 Signature power amplifier”, Hi-Fi+ Issue 179, January 2020

TL6.5 Series II | The Audio Beat

“Put the latest ‘6.5 alongside the original version and what you’ll hear is a quieter, blacker background, deeper bass and crisper, quicker dynamics. Bottom-end pitch and textures are clearer, and the Series II throws a much more developed and clearly defined acoustic around and beyond the orchestra … Instrumental separation is better (tonally and spatially), while melodic lines are clearer and more fluid, that newfound clarity in the bass bringing organization and purpose to the midband and treble.”

“This ability to cut to the musical core, to fasten on the expressive and emotive center in a recording — whether the recording itself is of audiophile grade or not – makes this a product for those with a genuine interest in and a system focused firmly on music.”

“The VTL TL-6.5 Series II doesn’t just take; it commands a place on the extremely short list of musically authoritative and satisfying one-box line stages”

Read the full review here…

- Roy Gregory, “VTL TL-6.5 Series II Signature Preamplifier,” April 30, 2018, TheAudioBeat.com

TL6.5 Series II | Audio Review (Italy)

“Conclusion” by Marco Benedetti

“I wonder too just because we know now for almost twenty years the seriousness with which Luke Manley and Bea produce their products; having already experienced the passage of 7.5 from Series II to III, I had a pretty good idea of what to expect; but, I repeat, the TL 6.5 II surprised me, the improvement over the old model goes beyond the most optimistic predictions, even reducing to a minimum the difference with more expensive and magical TL 7.5 III. VTL has struck again!”

 

“Listening” by M. Cives

If the previous (Series I) was a bargain at the time compared to the products of other vendors, this TL- 6.5 II brings the sound to realism due primarily to three parameters: rhythm, sound and spatial imaging. A revolution made by Luke Manley and Bea Lam for their wonderful, musical and technological products. To understand what a great step forward has been made, it should be pointed out the significant difference that exists between the two models being tested. In this listening sessions … was reinforced in me the idea of great seriousness of this product, In the case of VTL TL 6.5 II brought about a new standard for line preamplifiers, we’re on new parameters of sound reproduction that also differentiate them from the competition.”

Read the full review here…

- Marco Benedetti and M. Cives, “VTL TL6.5 II,” Audio Review Italy, 2017