VTL Preamplifiers

There are 4 preamplifiers in the range, with prices starting at £3450 going up to the heady heights of £25000. If you want your system to be engaging, musically involving with speed and dynamics previously unheard of in tube design a VTL preamp is a fabulous place to start.

The TL5.5 Series II is the most popular model in the range, although the TL6.5 is the star of the show (in my humble opinion) in terms of ‘bang for buck’. With the flagship TL7.5 the only thing to say is don’t hear one unless you are ready to spend some money, once a 7.5 gets under your skin there is no going back!

TL2.5i Preamplifier

The TL2.5i is an all tube preamplifier that has been very well thought out in terms of design. It offers 6 line level inputs, an optional internal phono stage (that can be fitted retrospectively), 2 pairs of outputs (one to your power amp, the other to a headphone amp perhaps?), an AV processor loop (to integrate into a surround system with ease).

The i in the name refers to an update which improved a number of components which has led to a dramatic jump forward in performance, the phono stage also received a respectable update with this i revision as well. Also a pair of gain switches have been added to the circuit giving increased flexibility.

At £3450 the TL2.5i offers great value for money and delivers a real slice of proper high end performance and a glimpse of what is to come as you move up the range.

  • Pure tube circuit with high current low impedance output
  • Drives amplifier loads down to 45kohm without audible bass roll-off
  • Stiff power supplies for each gain stage
  • 6 line inputs (5 with phono), 2 pairs single ended RCA outputs, 1 tape loop, 1 record output, 1 external processor loop for home theater
  • Optional internally retro-fittable phono stage for MM and MC
  • Remote volume control and mute
  • User Selectable Gain Switch (Normal and Low gain) in the Line Stage
  • Mono function for Line and Phono inputs
  • Simplest direct circuit path for purest musical sound and high reliability
  • Audiophile-quality 27mm laser-trimmed volume and balance controls
  • High quality VTL gold plated RCA jacks
  • High quality glass fiber circuit board with heavy copper traces
  • Heavy 16-gauge chassis construction, with well-shielded power supplies
  • Ultra-low-radiation power transformer design
  • Detachable IEC power cord

Optional internally retro-fittable phono stage for MM and MC:

  • User-selectable Load and Gain settings
  • Low-noise hybrid JFET design
  • User selectable MC Step-up transformer option for lowest noise
  • Improved filtering against RF interference

TL5.5 Series II Signature Preamplifier

The original TL5.5 was launched 20 years ago in 1997, it had a brilliant reputation and was incredibly well received back in the day. Obviously time has marched on and VTL have signficantly improved the design and performance with the Series II.

This latest version has borrowed many of the technological improvements that are found in the range topping TL7.5 and the TL6.5, the resulting sound produced by the TL5.5 is beguiling, detailed but silky smooth, dynamic and musical without ever sounding harsh or metallic.

It retains the basic all-tube circuit topology of the original TL-5.5 with a lower-gain, high-current 12AU7 tube circuit, a 12AT7 tube buffer, minimal negative feedback, and a low-impedance output stage (if you’ve read the the main VTL page you’ll remember these are good things!). It also features a new, precision-regulated power supply trickled down from the flagship TL-7.5.
The signal that passes through the 5.5 is fully balanced from input to ouput. There are 2 inputs which can be used with either XLR or RCA cables (please use XLR wherever possible!!), there are 5 line level inputs, 3 outputs (1 XLR, 2 RCA). Gain can be set to normal or low for added performance, headroom and flexibility. An AV bypass adds to flexibility as well.
As with the TL2.5i an optional internal phono stage is available as well.
The TL5.5 Series II Signature is £8000 on its own or £10500 with the phono stage fitted. To retrospectively add the phono stage costs £3000.
Features
  • Almost half the price of the TL-6.5 Signature Preamplifier
  • Luxurious cosmetics to match with Reference and Signature models
  • Fully balanced differential linestage with increased functionality
  • Optional internally retrofittable phono stage, with user adjustable cartridge loading and gain options
  • Precision-regulated B+ and B- supplies
  • Tube life extender circuit with B+ delay and soft filament ramp on power on
  • Balanced design, low-radiation power transformer
  • Quiet logic: Microprocessor sleep mode, quiet non-matrixing LED display with latching shift registers

Line Stage: All-tube, with lower gain high current 12AU7 circuit and 12AT7 buffer, minimal negative feedback

  • Two balanced /single-ended inputs, five single-ended inputs, one tape in, one balanced out, one single-ended out, one buffered record out
  • Soft-touch relay input select
  • 117-step chip-based differential volume control, with 3-digit display
  • Higher resolution via single higher-resolution attenuator, and software control for balance and offset
  • Switchable gain between normal and low gain
  • Mono control on front panel
  • Fully bi-directional RS-232 control: programmable input offset, any input programmable as pass-through, and input disable, tape monitor and Mono control on front panel
  • Two programmable trigger outputs
  • Full function aluminum metal remote
  • TP-6.5 chassis size with all precision machined aluminum cosmetic

Phono stage: JFET/parallel 12AU7 design from TP-6.5: 66dB gain balanced (23dB MC, 45dB MM)

  • Split-pole Passive RIAA with paralleled 12AX7 and 12AT7 gain stage
  • MM / MC select via jumper
  • MM Gain setting: fixed at 40 dB
  • MC Gain settings via jumper: 3 steps of 6dB: 66dB, 60dB, 54dB
  • Loading: MM 47k, MC: 100 ohm, 220 ohm, 470 ohm, 1K ohm, 47K ohm
  • Enhanced RIAA (selectable via jumper)
  • Rumble filter setting via front panel
  • Selectable bal/ S/E output via jumper
  • Dual-use buttons on front panel for phono-only functions
  • MC and MM gain trims

TL6.5 Series II Signature Preamplifier

As with the 5.5, the original TL6.5 preamp was a superb model, but with the Series II they’ve dramatically shifted the goalposts taking performance up several levels. This obviously shares a lot more in common with the 7.5 than the 5.5 and when you listen to it, it shows. It does everything the 5.5 does, but it simply does more, a lot more if truth be told.
Now £15000 is a lot of money and as a result the TL6.5 doesn’t sell in great numbers, but I can’t recall doing a demonstration of one that hasn’t resulted in someone being blown away and subsequently buying one.  You simply get more music, more dynamics, more transparency, more expression. It is utterly neutral in its presentation. The incredible dynamics extend further at both ranges of the spectrum without ever being aggressive at the top, bass notes dig low, remain controlled and clean and deliver real texture.

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

TL7.5 Series III Signature Preamplifier

The flagship TL7.5 Series III Signature is a 2 box affair, with a dedicated off board power supply to keep the pre-amp stage as pure as possible and free from noise and pollution from the power supply. As a result of this the 7.5 is classed as a hybrid design, the audio circuit has been designed to be as simple as possible (less is more!) with as little going on to the signal as possible, the fewer components there are in the signal path the better ultimately.

The new design features an extensively revised power supply based on current-sourced shunt regulator technology that minimizes impact on the audio signal by eliminating high voltage gain. 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 has been further optimised for linearity with zero global negative feedback in the circuit.

Sonically the TL7.5 simply pulls you in and will not let go. It delivers pure emotion and coherence. Allowing you to hear all of the musicians playing together as one, but enabling you to hear each individual element of the piece. It gives you more insight into recordings and you get that good old hi-fi cliche of being able to hear subtle nuances (and some not so subtle!) in recordings you thought you knew inside out!

The best advice I can offer with this preamp is not to hear it unless you are ready to buy one as once you’ve lived with it in your system going back is almost impossible to do!

The TL7.5 Series III Preamplifier is priced at £25,000.

Features

  • Isolated Control Unit chassis with 12 separate fully regulated power supplies
  • Separate Audio Unit chassis with zero internal digital activity and isolated from AC and power supply noise

Audio unit 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
  • 30 microfarad output capacitors for vastly improved bass control
  • Tube complement: 2 – 12AU7 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, using low signal instrumentation ruthenium relays for greatest resolution
  • Microphonically damped tube gain stage for greater vibration noise elimination

Control power supply unit features

  • 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
  • 4 separately programmable trigger outputs
  • Bi-directional RS-232 interface
  • Programmable input offsets
  • Selectable padded inputs
  • Rigid Combination steel and non-magnetic chassis and machined aluminum remote wand
  • Factory upgradeable from Series I and Series II

Audio unit features

  • New FET device output stage for more tube-like sound and simpler circuit
  • New device in the gain stage 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 Mundorf capacitors in signal path with bypass system for improved HF resolution

Control power supply unit features

  • Vastly improved lower impact and greater precision-regulated current-sourced shunt power supply
  • Teflon power supply bypass caps for improved top end
More Reading

Roy Gregory Hi-Fi Plus Magazine (TL7.5 Series III Signature)

The Absolute Sound (TL7.5 Series III Signature)

Ken Kessler Hi-Fi News Magazine (TL5.5 Series II Signature)

The Absolute Sound (TL5.5 Series II Signature)

Related Items