Recording Magazine (June 1999)
By Bob Boss
Time for a pop quiz.
The current popularity of tube-based outboard gear is the result of:
A) The inherent “warmth” and “fullness” tube circuitry imparts to audio signals
Careful! Are you sure? Okay, okay, let’s try an easier one.
The current popularity of James Demeter’s tube-based gear is the result of:
A) Excellent sound quality
B) State-of-the-art performance
C) Topnotch design and construction
If you answered “all of the above” to that question, you’re right. The Demeter Amplification brand name has been at the forefront of the tube love affair in pro audio, with an emphasis on “pro.” Their all-tube VTMP-2 Microphone Preamp and VTDB-2B Direct Box are practically industry standards amongst those who can afford the best.
Recently Demeter introduced the H-Series, a line ofoutboard micpres, compressors, DIs, and eqs that combine tube and solid state circuitry in the audio path. While hybrid circuitry is nothing new (though it may surprise you to learn how many alleged “tube processors” rely on solid state components for much of their circuitry), for the first time it brings Demeter outboard gear within reach of those with a smaller budget.
Demeter has chosen to use tubes for the amplification functions, with solid state components handling the driver functions. Each 12AX7A tube is supplied with 200 volts from a fully regulated power supply, enough to put to rest any question of whether they’re using “starved plate” techniques. Metal film resistors, film capacitors, and custom toroidal power transformers are standard accouterments, and all H-Series boxes feature AC voltage selectors for international usage.
I got to spend several months with the HC-1 optical compressor and HM-l mic preamp. Each unit occupies a single rackspace steel chassis with a brushed aluminum faceplate finished in attractive indigo.
The top panel is well ventilated over the main PC board holding the tube(s) (being a 2 channel unit, the mic preamp features two 12AX7As), yet these units still run moderately warm. I)d recommend keeping a blank space above them if you’ve got the real estate, though they showed no audibly adverse effects when squeezed into a rack with no room to spare.
Oh, and if you do squeeze them into a “portable” rack, be sure you’ve been pumping iron, the H-Series are heavier than your average single space rack boxes, a result of their substantial power transformers, their heavy-duty construction, and, I suspect, their elite heritage.
HM-1 Mic Preamp
The two channels of the HM-1 are identical, both featuring a low-cut switch, mic pad switch, phantom power switch with indicator LED, phase reverse switch, meter sensitivity switch, separate gain and volume potentiometers, and a l0-segment LED VU meter. Inputs are via rear panel XLR-M jacks, rear panel 1/4″ TRS jacks, and front panel 1/4″ TS jacks.
The front panel connectors are instrument level inputs, so in addition to fine microphone preamps you’ve just acquired a pair of genuine Demeter tube DI’s. Congratulations!
The rear panel 1/4″ input jacks are surprisingly not dedicated line level inputs per se, though the HM-1 certainly excels at conditioning line level signals with its tube circuitry. Those 1/4″ inputs are paralleled with the XLR connectors, essentially alternate balanced mic inputs offering the same gain range (30 to 60 dB, with an additional -20 dB courtesy of the pad switch) and the same Jensen input transformers.
This is good news for anyone who’s got a microphone with a 1/4″ plug, acceptable for all but the most excessively hot line level signals, but bad news if you forget to turn off the phantom power before using those TRS jacks. The line-level outputs are both XLR-F and 1/4″ TRS jacks.
The low cut filter engages a bit higher than I would ordinarily place it for some signals (e.g. baritone vocals, snare drums, or horns), but Demeter has wisely set the slope to an extremely gentle 6 dB/octave. The net result is quite effective and pleasing; I find the bottom end of those afore-mentioned signals overly attenuated, yet rumble, wind, stand noise and subsonic garbage was most definitely subdued without the potential phase shift a steeper highpass filter might introduce.
Metering is concise yet informative. The LEDs indicate the output level in standard volume units, with three segments from -20 to -7 in yellow, three from -5 to 0 in green, and three from +1 to +3 in red. Demeter claims an additional 18 dB more headroom is available above the meters’ highest indication, so output distortion is unlikely. This VU meter reflects the output level post-volume pot, so it is an accurate representation of what’s being sent downstream.
An independent red overload LED indicates the onset of distortion in the tube amplifier (pre volume pot) and yes, it’s quite easy to generate distortion at this stage of the mic pre. A bit of this “tube grunge” is a nice addition to the HM-l’s timbral palette, but I found overdriving it hard with direct guitar signals (overload LED on constantly) a very poor substitute for conventional guitar distortion.
Generally you’ll want to set the levels with the gain pot at a low enough level so as not to light the overload LED too often, and then use the volume pot to match output levels to your target destination. Hats off to Demeter for the separate input and output level pots; this allows for proper gain staging, creative use of tube saturation, and (thanks to the volume control’s infinite attenuation) manual fades.
And if solid construction, a full complement of features and functions, and ease of use don’t impress you, the sound definitely will. This preamp has an impressive effect on every microphone plugged into it (impressive in the sense of “radically subtle”; how’s that for an oxymoron?). No matter what type of mic I was using, or what console or outboard preamp I was using, when I swapped in the Demeter everyone heard a marked improvement in sound quality.
The HM-1 brings out details with a microscopic clarity. Unlike some tube gear, it does not cloud over or thicken low and mid frequencies, but represents them in in a more rarified light while highlighting punch and punch and presence. Some mice preamps are coveted for their coloration, others for their accuracy; the HM-1 seems to fall in between these categories, neither overtly “tube-y” more clinically flat (yet most definitely covetable).
I first used the Demeter on piano, miked with a Shure VP88 stereo condenser. Despite the player’s (free-jazz maven Matthew Shipp) enormous dynamic range, the HM-1 hung tough, resolving low level sages cleanly and noiselessly whiIe enduring pounding onslaughts with no trace of distortion.
On lead vocals for a live top-4O showband, the HM-1 turned a mere handheld SM58 into a laser beam of lucidity. When I patched it around the stock preamps in a Crest GTx console, the singer’s voice became so full, so incisive without being harsh, so roundly intelligible and clear, that the system tech begged me for 50 more channels of Demeter to replace all his preamps (and every time I mix for them now he asks “Can you bring that Demeter preamp again?”)!
Back in the studio the HM-1 was the hands-down winner of an informal listening comparison between several other mic preamps (some stand-alone, some built into mixers, all less expensive, so it should win).
Of the bunch, it seemed to the most gratifying sound with least blatant coloration. And even when A/Bed between the all-tube Demeter VTMP-2 mic preamp (which retails for twice again what the HM-1 costs), the H-Series box held its own; only on extremely challenging sources such as pianissimo female vocals or solo violin was the difference by any useful measure, and then only when auditioned with premium large-diaphragm condenser mics.
As a stand-alone DI the HM-1 yields all the sonic benefits I attributed to their VTDB-2B direct box in my July 98 review (natural sounding, “hyper-realism,” etc.) but it has the added advantage of being able to drive line-level inputs directly. Again, overdriving the HM-1 to generate tube distortion from direct guitar signals probably won’t be the most desirable experience. But minor changes to the range of the gain pot did yield perceptible changes in the guitar’s sonic fingerprint, as if the amount of amplification correlated to a focusing on different aspects of the instrument’s signature: pristine transparency, greasy phat booty, or anywhere in between. Feeding the HM-l’s mic inputs from external DIs was equally rewarding, as the preamp revealed details (both strengths and weaknesses) in those devices that standard console preamps seemed incapable of resolving.
This preamp will revitalize your mic collection and turn a few heads. Two thumbs up.
HC-1 Optical Tube Compressor
The Demeter HC-1 aspires to provide the classic sound of vintage optical compressors with “digital-ready” audio specs and the features and versatility demanded by contemporary engineers. Controls include attack and release times, compression amount, and volume (output level), with switches to select input sensitivity, low frequency sensitivity (sort of a side chain spectrum shaping switch; see below), meter sensitivity, stereo linking input/output meter select, and compression bypass.
Gazintas and gazouttas are available on both the XLR and 1/4″ TRS jacks. The input/output meter is identical to the VU meter on the HM-1 in calibration and color coding. A gain reduction meter (labeled “change”) is calibrated from -30dB to -1 dB. Curiously the HC-1’s gain change meter is entirely lit up when no gain reduction is present; the individual segments are extinguished to left as gain reduction exceeds their marked value This is basically backwards from most compressors I’ve used with LED ladder-type meters, and this took me a while to get used to this quirk.
Astute readers have probably already noticed the lack of either threshold or ratio controls, and the sole compression amount pot is calibrated in dB of gain reduction (from 0 to 20). I had to remind myself that this approach was modeled after vintage UREI LA-2A optical tube compressors, after which operation became predictable (come to think of it, the LA-2A’s mechanical meter indicates gain reduction from right to left also).
The low frequency sensitivity switch offers two positions: normal and high freq. In the high freq mode, a highpass filter in the side chain reduces the compressor sensitivity to low frequencies. This is not a typical de-essing circuit; although it can allow the HC-1 to function as a high frequency-only compressor, the turnover of the filter is too low to work effectively at isolating sibilance. It does however allow the compressor to function more discreetly on vocals, bass guitar, and full program material.
But in the normal mode, this compressor is anything but subtle. While its gain reduction action can be easily set up for a fairly mild effect, the timbral coloration of the circuitry seems evident at any compression amount. Fortunately, it’s the type of coloration that vintage tube optical compressors are renowned for: thick, round, warm, a bit splatty. Demeter definitely got the sound right with this unit.
Combining the modern flexibility of attack and release controls with this vintage sound yields even more versatility. Vocals get lush and present as if the mic has been jammed into the singer’s mouth. Boomy kick drums become firm and dense. It makes bass guitar positively delicious-the top end is pushed forward, accentuating finger and string noise just enough to suggest intimacy without getting harsh, squeezed or spitty and the bottom end gets rotund and supple without ever growing sloppy.
I did find myself gravitating to the HC-1 more for its timbral qualities than its gain reduction capabilities. when I wanted thick meaty low end it was trivial to achieve; when I wanted strictly managed and contained levels it was far less easy to achieve without introducing more conspicuous sonic artifacts (such as thick meaty low end)!
In another of my infamous informal subjective side-by-side comparisons, The Demeter HC-1 was more colored than any of the other units (which in this case included a Drawmer DL251, AudioArts 1200, Aphex 661 Expressor, and Empirical Labs EL-8 Distressor) but it was generally the preferred processor when a conspicuous effect was desired. When subtle, imperceptible gain control was the desired goal, the HC-1 fell to the bottom of that list, though I confess this may have much to do with it having the least intuitive user interface.
If you’re looking for a tube compressor to warm and fatten up your tracks, without having to spend a small fortune and without having to put up with the questionable reliability of vintage equipment, the Demeter HC-1 might be just the ticket.