TL Audio VTC 24 Channel Valve Mixing Console

Anyone who has used TL Audio valve outboard equipment knows how it can transform the sound of recording. Whether it's our preamps, equalisers, voice processors or compressors, the feedback we have had over and over again is "If only I had a console which could deliver this kind of sound!"

Well, now you can have it.

The VTC (Valve Technology Console) is a fully modular in-line multitrack mixer that offers all the benefits of the compact 8 buss / multiple tape output format but with the supreme advantage of TL Audio's critically acclaimed valve circuitry - which forms an integral part of the channel, monitor, group and master section signal paths. Available in configurations from 16 channels to 56 channels, with optional bar graph meterbridge, the VTC combines the classic warmth of valves with the functional demands of modern music production.

There are hundreds of consoles on the market. But none that sound, feel or look like this one. - Believe us - the VTC simply has no competition!

"Essential Valves"

The inclusion of valves in the VTC is not just a token addition. They form an essential part of the signal path at several key points within the console: every Channel and Mix B preamp incorporates an ECC83/12AX7A valve stage, as do the Group, Mix B and Stereo master mix amplifiers. This means when recording to tape via a group, the signal passes through two valve stages (channel and group), plus two more stages on mixdown (tape return and stereo buss) - giving a total of four valve stages in the signal path.

In common with our Valve Classics products, each valve stage in the VTC is run from a 250v DC stabilised power source.

"Cool Mixing"

The siting of the valves within the meter bridge section of the VTC means that any heat produced travels upwards and out through the vents in the bridge. As a result the audio electronics and control surface of the VTC remain comfortably cool! The valves within the bridge are easily accessible for servicing without the need to remove console modules.

"Serious Design"

In an age of cheap and cheerful console design, the VTC is a breath of fresh air. Built around an extra tough steel frame, each channel is modular and connects via two multiway connectors mounted on a rigid backplane, allowing easy removal and replacement. The frame is assembled in 8 channel sections, allowing a small frame desk to be expanded at a later date if required. All VTCs are supplied with heavy American oak side cheeks and buffer rail to complete that vintage-yet-contemporary look.

All internal signal busses are balanced for maximum signal integrity. The PSU is a custom designed linear supply, with local power regulation provided in each 8 channel section. Regular TL Audio features like 1.6mm glass fibre pcbs, 1% metal film resistors, over-rated valve stage capacitors and gold plated ceramic valve bases are of course a standard feature.

VTC Input Module

The VTC input channel is typical of TL Audio's approach to ergonomics - a superb combination of flexibility and ease of operation.

Input Stage:

The mic preamp stage is one of the key weaknesses on so many consoles, which is why the demand for separate high quality outboard mic preamps has become so intense. In contrast, the VTC's mic preamp is one of its great strengths, since it is the same design that has made our own valve mic preamps so sought after. Combining an SSM 2017 solid state stage with an ECC83/12AX7A secondary valve stage gives the VTC mic pre the ideal combination of low noise performance (-127dBu) and rich valve warmth. Preamp facilities include variable input gain (16 to 60dB), 48v phantom power, phase reverse and a 90Hz low cut filter (12dB/octave). A switch selects mic or line sources, and the input gain control, phase reverse and low cut filter are active on either mic or line input.

Like the channel preamp, the tape return preamp stage features an ECC83/12AX7A valve stage plus a +/- 20dB trim control and an internal -10/+4dB level matching link, allowing easy interfacing with any conceivable tape or hard disc recording system. A 'Flip' switch reverses the inputs, allowing the tape return signal to be routed through the main channel signal path, while at the same time feeding the channel signal through the Mix B section - ideal for mixdown.

Auxiliary Sends:

The auxiliary section of the VTC is a combination of simplicity and flexibility. Six mono auxiliary sends are accessed via four level controls, since aux send controls 3 & 4 on each channel can be shifted to feed sends
5 & 6. Auxiliary sends 1 & 2 are set post fader, while auxes 3 & 4 (and hence 5 & 6) can be switched to be pre or post fader - and additionally can also be fed from either the channel or Mix B signal paths. A separate stereo auxiliary send (7 & 8) is perfect for use as a headphone cue send or standard effects send: it has both a level and a pan control, and can also be switched pre/post fader and fed from either channel or Mix B paths.
Each send can be completely muted by individual on/off switches: thus preventing any low level bleed-through of effects and allowing an instant A/B comparison of dry and processed signals.

EQ Section:

Central to the channel strip is an extremely powerful four band EQ section employing two fully parametric mids. TL Audio equalisation is legendary, and the VTC's EQ stage shares the warmth, transparency and smoothness of our outboard equalisers. The HF and LF bands both offer a shelving type curve, giving +/- 15dB at 12kHz and 80Hz respectively. The lower and upper mids provide superb overlap and flexibility: both bands offer +/-15dB and variable Q between 0.8 and 7 (1.25 to 0.15 octaves), with the LM operating between 50Hz and 2kHz and the HM reaching from 500Hz to 18kHz. An 'EQ ON' switch with status LED allows an easy comparison between flat and EQ'd signals.

MIX B Section:

The Mix B section (traditionally called the monitor) is based around a high quality Alps 60mm fader, allowing accurate control of the tape return signal. Solo and Mute switches are also provided along with a pan control. The Mix B signals are all mixed and fed to a separate pair of outputs in the master section (allowing an entirely separate mix to be processed - hence the name!), but they can also be fed in the normal way into the main stereo mix via a switch and level control in the master section.
Indication of internal signal level is provided by signal present and peak LEDs.

Some or all of the channel EQ can be applied to the Mix B signal: the ‘HF/LF EQ’ switch places the HF and LF controls into the Mix B path, while ‘HM/LM EQ’ does the same for the mids.
Three more switches complete the Mix B section. 'Stat' and 'Auto' switches are designed to work with a third party automation system: the ‘Stat’ switch allows local status switching while ‘Auto’ allows a channel's automation stage to be bypassed if required. Finally, the 'Srce' switch routes the main channel signal into the Mix B section as well, allowing a separate mix of the main channel signals to be set up on the Mix B faders.

Channel Routing And Fader Section:

The main channel fader is a high quality 100mm Alps type, and pan, mute and solo functions are also provided. ‘Stat’ and ‘Auto’ switches perform the same functions for the channel as those in the Mix B section, while routing to the eight groups and L/R buss is provided via a bank of switches alongside the channel fader. The 'buss' switch extends the flexibility of the VTC's routing system: when the ‘buss’ switch is activated on a channel, it feeds the output of the relevant group fader through to that channel's tape output (see box). When the ‘BUSS’ switch is released, the channel tape output functions as a standard pre-fader direct output. This arrangement allows the VTC to feed multitrack tape or hard disc without any re-patching. Signal present and peak LEDs complete the channel section.

VTC Bussing:

Each of the VTC's 8 group faders is designed not only to feed their relevant group outputs, but also to feed a number of tape outputs simultaneously. For example, the signal from group fader 1 will route to each of tape outputs 1, 9, 17, 25 etc provided the "Buss" switches on those numbered channels are depressed (though the channel itself functions normally with whatever signal is being routed through it). Similarly group fader 2 will feed tape outputs 2, 10, 18, 26 and so on.

VTC Master Module

Like the input channel, the VTC master section is a triumph of intellegent, uncluttered design.

Auxiliaries:

Master aux send level controls are provided which allow complete attenuation through to +15dB of gain, along with AFL and mute switches. Six stereo returns are included with high quality Alps 60mm faders controlling the return level, working in conjunction with a balance control. Each return has individual mute and solo switches, plus routing to the headphone sends: each return can individually route to both phones outputs via a separate level control.

Phones Matrix:

The VTC has two separate phones outputs, each with a level control and solo facility. Each phones output can be fed by any combination of control room output, mix B output, aux 3/4, aux 7/8 and 'external' (a separate pair of inputs which are designed for a click track etc).

Control Room Section:

The control room output can be fed from any combination of L/R Mix, Mix B, 2TA, 2TB (both two track returns) and 'external'. A large level control is easy to grab in a hurry! A separate PFL trim control is provided (with +/- 20dB of gain), and switches allow an alternate L/S output to be fed, and the control room output to be checked for mono compatibility. Two solo modes are provided on the VTC: PFL or Solo in Place. A switch in the control room section allows Solo in Place to be selected.

Studio Output Section:

A separate section allows the studio output to be fed from any combination of sources: L/R Mix, Mix B, 2TA, 2TB or ‘external’. A "Follow C/R" switch allows the studio output to automatically follow the settings of the control room source switches, and two more switches allow the Studio output to be solo'd or muted. Finally, a level control is provided to set the overall studio output level.

Talkback:

The talkback section allows the talkback mic to be fed to any combination of 'tape' (i.e groups and stereo mix), studio output, phones 1 and phones 2. A separate talkback level control is provided, along with an illuminated talkback switch which can be internally set for latching or non-latching operation. When activated, the talkback switch automatically dims the control room output by 20dB.

Oscillator:

An internal oscillator can be switched to generate 1kHz or 10kHz tones, with a separate level control and on/off switch. The oscillator routes to both groups and L/R Mix.

Mix B Master:

The Mix B signals can be routed solely to the Mix B outputs, and also to the main L/R mix via a separate switch. An associated level control governs the amount of signal sent to both destinations.

Group Section:

Eight 100mm Alps group faders are provided, each of which can be solo'd or routed to the L/R mix. When fed to the L/R mix, each group can be routed in mono equally to both left and right busses, or routed hard left or right.

Master Fader:

A 100mm Alps stereo fader allows control of the stereo mix level, and like the channel faders is fitted with 'Stat' and 'Auto' switches for use with third party automation systems.

Options

VTC Meterbridge:

All VTC consoles are supplied with a standard meter bridge, which offers VU metering of all eight groups plus the stereo L/R master. Each meter has an associated peak LED which illuminates at approximately 18dB of output level.

An optional meter overbridge is available which provides 16 segment bar graph metering of each channel and the L/R master. A global switch on the meterbridge allows either tape output or tape return to be monitored. This optional meter bridge is fitted above the standard bridge, and connects via 25 way D-type connectors on the rear of each 8 channel section.

VTC Specifications

Input Impedance (electronically balanced):

• Mic input: 2.5k ohms
• All other inputs: 10k ohms minimum

Output Impedance:

• All balanced outputs: 100 ohms
• All unbalanced outputs: 47 ohms

Maximum output levels:

• Direct, Group, L/R (balanced): +26dBu
• L/R (unbalanced): +20dBu
• Insert sends: +20dBu

Maximum Gain:

• Mic input to direct output: +70dB
• Line input to direct output: +32dB

Frequency Response:

• Mic input @ 40dB gain to direct output: 20Hz to 20kHz +0, -1dB

Mix Noise:

• Main L/R output (reference to +4dBu nominal):
• Master fader down: -97dBr
• Master fader @ 0dB: -89dBr
• with 32 channels routed, faders @ 0dB, channels open: -75dBr

Group Noise:

• (reference to +4dBu nominal)
• Fader down: -94dBr
• Fader @ 0dB, no channels routed: -92dBr
• with 32 channels routed, faders @ 0dB, channels open: -75dBr

Input Noise:

• Mic Input Equivalent (EIN): -127dBu
• (22Hz to 22kHz, 150 ohm termination, 60dB gain)

THD+Noise:

• (From 10Hz to 40kHz @ 0dBu)
• Direct output: 0.02%
• Groups: 0.03%
• L/R: 0.03%

Crosstalk:

• Line input to adjacent channel: -100dB @ 1kHz, -83dB @ 15kHz

Channel Connections:

• Mic input: XLR (balanced)
• Line input: Stereo jack (balanced)
• Monitor return: Stereo jack (balanced)
• Internally jumpered for -10/+4dBu
• Insert point: Stereo jack (tip=send, ring=return)
• Tape/Direct output: Stereo jack (balanced)
• Internally jumpered for -10/+4dBu

Master Connections:

• Main output: XLR (balanced, +4dBu) and mono jack (unbalanced, -10dBu)
• Main insert point: Stereo jack (tip=send, ring=return)
• Studio output: Stereo jack (balanced)
• Control room output: Stereo jack (balanced)
• Phones outputs: Stereo jack (unbalanced)
• Group outputs: Stereo jack (balanced)
• Group insert points: Stereo jack (tip=send, ring=return)
• Auxiliary sends: Mono jack (unbalanced)
• Auxiliary returns: Stereo jack (balanced)
• Mix B output: Stereo jack (balanced)
• 2 track returns: Stereo jack (balanced) Internally jumpered for -10/+4dBu
• External input: Stereo jack (balanced)

Dimensions (mm):

(console only without patchbay, excluding stand and packaging):

• 16 channel: 300(H) x 1180(D) x 975(L)
• 24 channel: 300(H) x 1180(D) x 1280(L)
• 32 channel: 300(H) x 1180(D) x 1590(L)
• 40 channel: 300(H) x 1180(D) x 1900(L)
• 48 channel: 300(H) x 1180(D) x 2200(L)
• 56 channel: 300(H) x 1180(D) x 2510(L)