DRAWMER Tube Station 1

Nov 1, 2003 12:00 PM, By Myles Boisen

Drawmer, a respected British manufacturer of midpriced pro gear, is reaching out to the personal-studio and gigging musician with its Tube Station 1 (TS1). The processor combines a Class-A mic preamp, a high-impedance instrument preamp, a stereo compressor, a tube circuit for coloration, a highpass filter, and an optional 24-bit, 96 kHz A/D converter. The TS1 can be used as a single-channel voice processor, channel strip, or stereo compressor; add the A/D card, and it can act as a front end for a DAW.

Like all Drawmer gear, the TS1 is built to last. Housed in a 1U solid-metal chassis, the look is basic black with easy-to-read white and red labels. The only concession to fashion is a swirly red logo that alludes to the symbol used at London Underground stations, known colloquially as “tube stations.”

ALL ABOARD

FIG. 1: The front panel of the Tube Station 1 is clearly laid out and easy to use. The compressor section features a one-touch Compress control as well as Attack and Release knobs.

The TS1 front panel is divided into seven subsections corresponding to the internal signal flow (see Fig. 1). First on the left is the Input section, which includes a ¼-inch high-impedance jack (identified by a picture of a guitar), a preamp input switch, and status LEDs that show whether the instrument or the mic input is being used. The XLR mic input is located on the rear panel next to the ¼-inch preamp output and insert jack (see Fig. 2). Also on the rear panel are a pair of line-level XLR inputs, a pair of line-level XLR outputs, and a TRS sidechain jack. The optional A/D card offers rear-panel AES/EBU I/O on an XLR jack, S/PDIF on an RCA jack, a BNC word-clock input, and sampling-rate selection switches. The card converts the signal to 24 bits without provisions for dithering to 16 or 20 bits.

FIG. 2: The rear panel gives you stereo line-level I/O for using the TS1 as a stereo compressor. The XLR mic preamp includes a balanced 1/4-inch insert point and a preamp output. The digital output card appears on the left of the panel.

Moving to the right on the front panel, the Front End section has a continuously adjustable input gain control with instrument gain values (ranging from -20 to +40 dB) marked in red and microphone gain values (ranging from 0 to +60 dB) in white; a red LED next to the control indicates clipping. The 48V phantom-power and polarity-reverse switches are accompanied by red status lights, and this section also includes a highpass filter, which ranges from 25 to 250 Hz, and a control labeled H.F. Contour that adds a broadband high-shelving boost.

The Compressor section has a source switch that selects either the mono front-panel input or the two rear-panel line inputs. The Compress knob controls input gain to the compressor circuit and is marked 1 through 10 (those values bear no relation to a decibel scale). The compressor uses VCAs for dynamic control and has a fixed, nonadjustable threshold: increasing the Compress value produces higher gain and more compression. Next to the Compress knob are standard continuously variable controls for Attack (from 0.5 ms to 50 ms) and Release (from 0.05 seconds to 5 seconds); below the knobs, an LED ladder indicates the amount of gain reduction.

Unlike most compressors in its price range, the TS1 compressor has no individually adjustable parameters for 2-channel mono operation. That doesn't mean you can't use the unit on two different signals at once, but it does limit an engineer's options.

The Tube Drive circuit uses a pair of ECC83/12AX7 vacuum tubes to increase the amount of harmonic distortion in the signal. Smartly, Drawmer made the effect bypassable rather than simply creating a hybrid circuit for tube coloration. Controls in the Tube section are an Active switch with a status light, and a continuously adjustable knob (ranging from 1 through 10). With Tube Drive bypassed, the signal path through the inputs and compressor is entirely solid-state.

Because the TS1 is essentially solid-state and is marketed as a “stereo vacuum tube compressor with instrument and mic pre,” I asked company founder Ivor Drawmer for clarification. “The TS1 is a compressor with a tube,” he said. “We figured it was better to make the tube available or not, because we would be asked why the tube can't be switched out. Of course, a real tube compressor uses all tubes, weighs a ton, and doubles as central heating.”

The next two sections have to do with output gain and metering. The Trim control has a limited range (-30 to +5 dB) and controls the level after the compressor but before the limiter and the A/D converter. For digital output from the unit, Trim is the final gain control. After this point in the circuit, the signal is sent to a fixed threshold limiter (set at +16 dB, or 12 dB above 0 VU referenced to +4 dBu), which has a status LED but no bypass switch.

The Analogue Output knob, which ranges from off to +16 dB, is the final gain control for the TS1's XLR outputs. Below the Trim and Output knobs is the unit's master digital-output-level meter. A bypass switch to the right of the meter disables all compression and gain; when the switch is engaged, the meter indicates input levels. A power switch and status LED are on the far right.

JUST THE FACTS

The TS1 manual covers only the basics. The illustrated descriptions of each control are clear and concise, and it includes a few diagrams of common setups.

Technical specifications about the unit's filters, compressor ratio, and even the bit rate of the A/D converter are conspicuously absent. Considering the TS1's versatility and its many possible operational modes, I was surprised that the manual contained no practical or creative user tips.

DI ANOTHER DAY

A custom Telecaster guitar seemed to lose a little bit of midrange warmth when preamplified by the TS1 (using the TS1's ¼-inch preamp output at unity gain, with no tone controls active and no compression) and then run into an all-tube Fender Pro Jr. But I got a kick out of playing through the unit and could imagine it catching on among tech-savvy instrumentalists onstage. The Drawmer's preamp gain boost was very useful and added a convincing crunch when set at about +35 dB. I also enjoyed using the unit's high-frequency contour knob, which can function as a smooth and subtle alternative to the “bright” switches on many guitar amps.

Running the guitar signal from the compressor out jack allowed me to audition the Drawmer's onboard tube processing, which seemed surprisingly subtle with this guitar and amp combination. And in contrast to most compressor stomp boxes, the Drawmer's dynamics were a dream. Regardless of the playing style, the TS1's compressor was always transparent and gentle, with the attack-time adjustment being a major plus.

In studio testing on a variety of vocal and instrumental tracks, the TS1's class-A mic pre was a solid performer. My studio partner, Bart Thurber, and I found it to be consistently reliable for definition, subtle ambience details, and flat response without sounding clinical. At its best — for example, when used with a Neumann TLM 103 as a distant mic for drums — the TS1 delivered a very hot, modern sound that rivaled any of the top-notch mic preamps in my racks. A touch of compression and an ample dose of the drive effect made the drummer (and all of us in the control room) very happy.

DRESSED TO COMPRESS

During a Pro Tools mix, the TS1 contributed positive tube attitude and much-needed sustain on a bass track. And yet, despite its sonic benefits, I got a bit annoyed during the final tweaking of a mix when I had to make multiple knob adjustments on the TS1 to hear less compression while keeping the output level the same. I also wished Drawmer had included a limiter bypass switch, as I was getting audible transient distortion on the bass track anytime the limiter LED lit up.

PRODUCT SUMMARY Drawmer Tube Station 1 channel-strip $850 with digital I/O $1,150
FEATURES	4.5
EASE OF USE	4.0
DOCUMENTATION	4.5
VALUE	4.5
RATING PRODUCTS FROM 1 TO 5
PROS: Feature packed. Bypassable Tube Drive. Detailed mic preamp. Full-featured instrument preamp and DI. Transparent one-knob compression. Phase-reverse switch on front panel. Optional A/D converter. Sturdy construction.
CONS: Limiter cannot be bypassed. Gain staging and limiter not optimal for analog recording. No individually adjustable compression parameters for two-channel mono operation. Skimpy manua l.
Manufacturer Drawmer/TransAmerica Audio Group (distributor) tel. (702) 365-5155 e-mail sales@transaudiogroup.com Web www.drawmer.com

I liked the sound of this unit's compressor for mixing; a little tube drive and about 4 dB of gain reduction usually worked beautifully on a range of vocal and instrumental tracks. In the midst of my tests, I realized that the TS1 is similar in character to one of my favorite compressors — the venerable (and more expensive) Drawmer 1960. Drawmer's U.S. distributor informed me that the TS1's compressor circuit is closer in design to the company's revamped 1969 model, the version of the 1960 created by Mercenary Audio.

Auditioning a 16-track analog mix through my Soundcraft Spirit board and using an Apogee PSX-100 for A/D conversion to a Tascam DA-30 DAT recorder, I found that the TS1 passed pristine analog audio in bypass and active mode. My only complaint with the TS1 at this stage was that I couldn't set both gain controls to zero (supposedly unity gain) and get the bypassed and active levels matched up without some gain reduction taking place.

Because the Compress pot increases the input gain with a set threshold, I had to set the trim at -4 dB, increase the output to +12 dB, and bring the Compress control up to 3 in order to A/B my uncompressed levels reliably. Toggling between bypass and active modes at these settings, I was impressed to hear no change in audible noise level, and only a faint switch click in the audio. Engaging the compressor circuit with no gain reduction produced very subtle attenuation of high-end airiness on my horn-dominated mix, but no other coloration.

Bringing the Compress value up to nearly 4 (with Attack set at 15 ms and Release at 100 ms) yielded minimal compression, accompanied by a 3 dB increase in overall gain. At these settings, mix compression was smooth and undetectable. But a Compress value of 5 was way too much, producing pumping on the low end and audible high-end distortion artifacts when the brass lit up the limiter LED. Curiously, whenever the compressor and limiter were working simultaneously at noticeable levels, the TS1's output seemed a bit fuzzy or crunchy in the treble range.

Turning up Trim to produce more limiting revealed that the limiter is definitely of the brick-wall variety and optimized for digital use. This means that the TS1 can be used to deliver scorching levels on a two-track stereo mix bus to an analog or digital recorder. Even when used in this fashion for highly compressed mixes, the limiter would not distort or get fuzzy. I'd rather use a dedicated mastering compressor for final leveling, but the TS1 is certainly cleaner and gentler to full-frequency mixes than many comparable units I've used.

MIND THE GAP

I do have one cautionary note for anyone contemplating use of the TS1 in an analog studio. Because the unit's output metering is set up for digital recording, I often had to ignore the meter and push the output levels harder to get sufficient signal to my analog 16-track. In all instances the TS1's ample headroom and +16 dB-maximum output level control supported this practice without undue noise or distortion.

In addition, I found myself trying to work around the built-in limiter. In the absence of a simple bypass switch, I kept dynamic limiting to a minimum by attenuating the prelimiter Trim knob by as much as -20 dB. That kept the signal below the limiter's nonadjustable +16 dB threshold, necessitating corresponding makeup gain amounts of +10 dB or more. Although my work-around compromised the gain staging of the unit somewhat, it created no problems with noise. And in all trial applications, even with -10 dBv input signals, the TS1 never ran short of gain.

For a lot of the rock and blues recordings I do, the aggressiveness and authenticity of the TS1's tube circuit puts it in the most-likely-to-succeed category. However, for some sounds, such as bright vocals and acoustic guitar, even a little bit of the TS1's tube flavor can be too much. One male rock vocalist I recorded sounded too edgy with any amount of Tube Drive, even when using a common dynamic mic.

STATION TO STATION

There is certainly a lot to like about the TS1. In the basic analog configuration, it's a notch up in price from a lot of the competition, but it gets high marks for features, versatility, and audio quality. Every feature sounds good and is relatively foolproof, making the TS1 stand out from the crowd of multifunction boxes. A bypass switch or threshold adjustment for the limiter circuit would certainly broaden the TS1's appeal for combined analog and digital setups.

Although basic, the compressor in particular works smoothly and sets up easily. Additionally, the Tube Drive offers authentic tube flavoring that can be bypassed without a fuss. And the instrument preamp section adds a handful of creative options for tracking as well as gigging. Like its London namesake, the Tube Station 1 is a fast and efficient way to get your signals to the desired destination.

Tube Station 1 Specifications
Analog Inputs	(1) balanced XLR mic (+4 dBu); (2) balanced XLR line; (1) unbalanced instrument ¼" (-10 dBV)
Analog Outputs	(2) balanced XLR (+4 dB); (1) balanced ¼" output (+4 dB)
Other Analog Connections	(1) TRS ¼" preamp insert; (1) TRS ¼" compressor sidechain
Digital Input	(1) BNC word-clock input (on optional A/D converter card)
Digital Outputs	(1) AES/EBU; (1) S/PDIF (on optional A/D converter card)
Maximum Input Level	+21 dBu
Maximum Output Gain	+20 dBu
Frequency Response	12 Hz-52 kHz (-1 dB)
Noise	-87 dB (22 Hz-22 kHz)
Maximum Output Level	+20 dBu
Dimensions	1U × 9" (D)
Weight	9.5 lb.