TL Audio M1 Tubetracker

Worried that your digital recordings sound a bit sterile? Maybe the Tubetracker can warm things up a bit...

The new M1 Tubetracker console from TL Audio is essentially a reworked version of the company's previous M3 Tubetracker design that was reviewed in SOS in January 2002, and it follows in the footsteps of the larger M4 console, reviewed in December 2005. In fact, the M1 shares the same sonic characteristics and many features of the M4, and I would suggest re-reading that review on-line to help fill out the background to the M1.

Like its siblings and forebears, the new M1 is a hybrid console, featuring solid-state electronics for the bulk of the signal path, but with half a 12AX7 / ECC83 dual-triode valve stage incorporated within each channel, and another in the master stereo mix outputs, all running with a proper 200V anode voltage. The console is available in either eight-channel or 12-channel versions, and can be fitted with an optional eight-channel 24/96 ADAT card and a two-channel S/PDIF card to provide digital interfaces for the channels and master section, respectively. These are the DO8 and DO2 cards widely used in other TL Audio products.

Like other Tubetracker designs, the M1 has an inherently warm character, but managing the gain structure enables the tonal characteristics to be varied from clean-but-warm through to an obviously rich and slightly overdriven — but never unpleasant — sound.

The M1 is built very solidly and the 12-channel version is a heavy beast, which looks rather special with its oiled oak frame, dark blue colour scheme, and large, coloured control knobs. Each module is physically separate and plugs into a motherboard running across the bottom of the console frame, being secured by two screws. One of the more obvious changes from the M3 console design is that all of the I/O connectors are mounted at the top of each channel strip, which makes it much easier to see what is plugged in and to change configurations. The valves are mounted vertically on the motherboard, rather than on the channel cards themselves, but they are easy to access and change if necessary. Ventilation slots are provided at the top of each channel to help keep things cool. Power is supplied via a separate, chunky PSU module, which is designed for surface mounting rather than rackmounting. Unlike that of the M3, this PSU relies on convection rather than fan cooling, so it is completely quiet. The console is fitted with a captive cable which plugs into the PSU with a locking connector.

In terms of facilities, the M1 has been slightly simplified and updated from the older M3 model, but the basic signal path is the same. There are separate mic and line inputs on each channel, and the corresponding return channel from the optional DO8 ADAT card is routed via the break contacts on the line input socket. Phantom power is switchable individually on each channel, as are polarity inversion, mic/line selection, a 30dB pad and a 90Hz, 12dB/octave high-pass filter. A single gain control knob spans +16 to +60dB for the mic inputs, and ±20dB for the line input (with a centre detent at unity gain). Since the channel's triode valve follows the mic amp, the amount of coloration can be adjusted with the input gain setting, while the mix level can be controlled with the fader.

Fully balanced insert send and return TRS sockets are provided between the input stage (post valve) and the equaliser. Whereas the old M3 featured a four-band equaliser, the new M1 has a three-band EQ section with a single sweep mid, based very closely on previous successful TL Audio designs. All bands provide ±15dB of range with centre detents for unity gain, and an EQ bypass switch is provided. The top and bottom bands have shelving responses at 12kHz and 80Hz respectively, while the mid band can be swept between 150Hz and 7kHz. The filter bandwidth, or Q, is fixed, which is a little restrictive, but the whole EQ sounds musical and sweet.

Following the equaliser, the signal splits between the main signal path and a pre-fade direct output (at a nominal +4dBu) which also feeds the corresponding ADAT channel input. There are two auxiliary sends, the first of which is switchable pre/post, while the second is fixed post-fade. Each channel has a pan control, plus a PFL button, a mute button (which only affects the post-fade outputs) and a 100mm long-throw fader. The last feels very light in comparison to the rotary controls, which have a very solid and heavy action. A pair of LEDs are provided just above the fader to indicate Peak levels at +19dBu (7dB below clipping) and 'Drive' (between +4 and +12dBu). The latter refers to how hard the valve is being driven, which corresponds to the amount of valve coloration introduced ^— the brighter the light, the more bent the sound becomes!

A single stereo effects return channel is included (the M3 has two) in the master section, with balanced line-level inputs, a rotary 'fader' and a balance control. It is also equipped with PFL and a (post-fade) send to the Aux 1 buss so that, for example, a reverb return can be routed to the headphone cue mix.

The mixer features a stereo mix buss with a single stereo ganged fader and the outputs are presented on balanced XLRs. The single master fader is a big improvement over the split master fader arrangement of the M4. The output signal also feeds the optional DO2 stereo digital interface card, if fitted. The mix amp contains another triode valve stage, and by juggling the mix buss levels and the main output fader, it is possible to adjust the amount of valve drive and coloration once again. Both Aux outputs have master level controls and PFL buttons, and are output via balanced TRS sockets.

The monitoring section has four sources: the master stereo output mix, two stereo 'tape' returns, again with balanced inputs on TRS sockets, and the PFL source. The last automatically breaks in to the monitoring whenever a source is PFL'd, and a trim control is provided to balance the PFL signal level against the normal mix monitoring, which is handy if you are driving the input channels hard for effect.

The monitoring output feeds a pair of round, moving-coil VU meters, a built-in headphone amplifier and one of two stereo loudspeaker outputs (labelled Main and Alt). Although there is a monitor mute button, there are no mono sum, polarity reversal, or talkback facilities.

In Use

The M1 Tubetracker is clearly intended as a combined front end and analogue mix buss system for a DAW, but, much like the former M3 and current M4 models, it also has some built-in monitoring facilities, and it works very well, although there are a few niggles and caveats.

The optional ADAT interface card makes it very easy to route input signals direct to the computer when tracking, and with the benefit of analogue EQ if required. It also facilitates the routing of signals from the computer back through the desk for mixdown. The provision of two auxiliary sends makes latency-free cue monitoring easy to set up, along with an outboard reverb effect too. However, the lack of dedicated talkback is likely to be a major frustration if you have a separate recording area or vocal booth.

The ADAT card also seems very expensive, especially when you consider the fact that you can buy a complete eight channel mic amp with ADAT connectivity from Behringer for less than half the price of the card alone, and while ADAT is still a popular protocol, a Firewire card option would be even more attractive.

The Tubetracker's channel strip, which includes a bypassable, musical-sounding, three-band EQ based on successful TL Audio designs. While I'm nit-picking, I am slightly concerned that the valve stages can't be bypassed at all. The amount of non-linearity can be controlled to a degree by juggling gain structures through the desk, but the slightly warm and rich valve signature is always there — the specs quote 0.4 percent distortion at very modest +4dBu signal levels. The input signal must always pass through at least one valve on the way in to the computer, and two more valve stages when you mix down through the desk. It is sometimes possible to have too much of a good thing!

On the plus side, though, at least TL Audio have designed the console so that you can choose whether or not to record and mix with EQ (thanks to the post-EQ direct output and the provision of an EQ bypass button), something which is impossible with another popular analogue tracking console that is supplied with digital interfacing...

A common complaint made against the old M3 was the lack of master output insert points, and the new M1 suffers exactly the same failing. This omission makes it difficult and inconvenient to use an analogue buss compressor, for example, which seems rather daft given the raison d'être of the desk.

As a tracking mixer or input stage for a DAW, the M1 does a great job, with a sweet and musical sound character that is inherently flattering and easy to control. The EQ could be a little more flexible in terms of the mid-section bandwidth, but that is a minor point in comparison to the creative tonal shaping it affords. The fact that it can be switched out completely is also nice. My only serious complaint about the console for tracking purposes is the lack of built-in talkback to communicate with the performers. There are workarounds, of course, but at this price you shouldn't need to find workarounds.

As an analogue mix bus, the M1 performs well at a technical level, although I would have liked an option to bypass the input stage valve, to reduce the inherent coloration that quickly builds up with multiple passes through the desk. The absence of master insert points restricts the creative possibilities of the desk in a frustrating way.

The monitoring section also falls short in some key areas, most notably in not providing the option for listening to a mono sum and not being able to route a two-track return to the aux output as a headphone cue feed. Of course, facilities like mono sum and polarity reversal can, in some cases, be obtained within the DAW, but this might not be convenient when mixing down.

The M1 concept is excellent, the ergonomics are great, the interfacing is bullet-proof, with everything being balanced, and the desk looks and sounds fabulous! So it will prove popular, I'm quite sure. However, I can't help but feel that it has missed its intended target in several small but ultimately very frustrating ways. The issues highlighted above could be overlooked more easily in a budget console, but the M1 is not what could reasonably be considered a cheap desk at this price — especially with the ADAT and S/PDIF cards installed — and for that reason I found it slightly disappointing. Nevertheless, there is little direct competition and the M1 stands tall amongst its peers, with a sonic pedigree that will appeal to many as an antidote to the 'sterile' nature of digital and computer-based recording.