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Grace Design M103

Recording Channel Strip
Published March 2011
By Bob Thomas

Grace Design M103

Should you build outboard gear to do the job as well as possible, or to meet a price point? Grace Design prefer to do the former, and it seems to be a philosophy that pays off...

Since 1994, Grace Design have based their business strategy on designing audio products with features and facilities that audio professionals need, rather than building what they can to meet a particular price point. This approach apparently originates in a real commitment to engineering excellence in design, component selection and build quality.

Engineering Excellence

A product‑design strategy with engineering excellence at its core means that every aspect of a new device will be examined and honed to give ultimate performance, no matter how humble the part or how simple the circuit, so the purchaser will be buying something that's designed to deliver — and keep delivering for some considerable time — exactly what it is intended to deliver, and to an extremely high standard.

The slight disadvantage of this approach is that such devices inevitably end up being more expensive than some of the competition — if for no other reason than that it will tend to contain more expensive components. The faith that Grace Design place in this approach is reflected in the five‑year transferable warranty that is offered on all their products.

Fortunately for Grace Design (and for the audio industry at large) the old aphorism, attributed to Henry Royce of Rolls‑Royce fame, and more recently taken up by Gucci, that "quality is remembered long after the price is forgotten” means that, despite the vagaries of economic climes, there remains a strong market for quality equipment whose sonic performance and quality outweigh absolute price considerations.


The cleanly laid‑out front panel groups the controls logically, while at the rear there's a switch and socket to link two M103s for stereo operation.The cleanly laid‑out front panel groups the controls logically, while at the rear there's a switch and socket to link two M103s for stereo operation.

All of which brings us neatly to Grace Design's latest product, the M103 channel strip, which enters a crowded marketplace where, superficially at least, there's often little differentiation between the various units. In the case of the M103, differentiation begins with the engineering of its packaging. Rather than being held in place by the usual polystyrene or cardboard end cheeks, the M103 arrives safely suspended in space between two sheets of plastic film. I've not seen this approach before, but it makes so much sense for the transportation of delicate electronic apparatus. As a result, the outer carton is a lot larger than you might expect, but I wouldn't mind betting that Grace did their sums and concluded that obviating transit damage has a much greater benefit to them and their customers.

Removing the packaging reveals a slick‑looking, black, white‑lettered, chrome‑knobbed, 1U rackmount enclosure, whose 24 front‑panel controls and eight rear‑panel connectors hint at the device's possibilities. To further underline the engineering‑led approach, each front‑panel knob is fitted with a rubber ring around its circumference to ensure non‑slip ease of operation.

The M103 is, put simply, a mono channel strip, consisting of a microphone preamplifier, a three‑band sweepable EQ with a fully parametric mid-range, and a compressor. The unit carries three audio inputs: two rear‑mounted, balanced XLR connectors for microphone and line‑level sources, and a front‑panel, high‑impedance, unbalanced quarter‑inch jack for connecting musical instruments and the like — while the single XLR output is paralleled by both balanced and unbalanced quarter‑inch jacks. To improve its flexibility, the M103 also features line‑level balanced and unbalanced quarter‑inch jack outputs from its microphone preamplifier — which means that not only can you run the mic preamp independently from, or in parallel with, the EQ and compressor path, but also that you could simply insert your favourite bit of outboard into the signal path. It's amazing what good engineering and a couple of extra connectors can provide.

As I mentioned, the front panel carries the high‑impedance instrument input, alongside the combination of 13 knobs and 11 switches that together configure the ways in which the M103 operates. Inserting a jack into the front-panel input automatically bypasses the rear‑panel XLR mic input, which means that a microphone can be left connected without causing any problems when an instrument is being used to feed the M103 — another genuinely useful practical touch.


Grace Design M103

The M103's microphone preamplifier is based on that of Grace Design's own highly regarded, stand-alone M101 single‑channel mic preamp. As a result, the M103 is equipped with transformerless, fully balanced inputs, and its gain stages feature transimpedance (or current feedback) amplifier topology, based around Burr‑Brown OPA 134 Soundplus series audio op-amps.

Grace state in their literature that transimpedance amplifiers exhibit significant advantages over the more commonly used voltage-feedback amplifiers, namely constant bandwidth over a wide gain‑range, better dynamic performance and tracking of complex harmonics, greater detail, and a more open and musical sound quality. Furthermore, they believe that this sound quality is maintained all the way up to the highest sound levels, thus making them "dramatically superior” for use with low‑output ribbon microphones.

Emphasising the last point in hardware terms, the M103 features a specific 'ribbon microphone' mode, and engaging this locks out phantom power, bypasses the phantom power decoupling caps, and increases the microphone input impedance from 8.1kΩ to 20kΩ.

The voltage gain on the microphone input is adjusted in 5dB steps from 10dB to 65dB by a 12‑position, gold‑plated rotary control, via a bank of 12 0.5-percent‑tolerance, metal-film resistors. When the instrument input is used, the gain range is from ‑10dB to 45dB.


The switchable, three‑band EQ section has a fully parametric mid-range section and the sweepable low and high sections can be operated, independently, in either shelf or peak modes. Peak mode is used to cut or boost at a selected frequency, whilst shelf mode boosts or cuts all frequencies above (for the high band) and below (for the low band) the set frequency. Each section has 12dB of cut or boost and this, coupled with the well‑chosen frequency ranges and a small but sensible amount of overlap between the bands, results in a precise but powerful EQ.

The M103's compressor is a new design based on an optical attenuator, and although not designed for 'brick wall' limiting, it provides compression ranging from light to heavy without sacrificing neutrality and/or transparency. This is a manual compressor with no 'auto' mode, so you'll have to get involved with its threshold, attack, release and ratio controls. In addition to the front‑panel controls, the compressor is also equipped with an external side‑chain input, which allows for ducking and de‑essing functions. If you are fortunate enough to be able to justify owning two M103s, you can link the compressors for stereo operation through the side-chain inputs. To give added flexibility, the compressor can be switched to be either before or after the EQ, the choice of which is entirely dependent on the ears of the engineer.

The M103's signal path concludes by passing though a trim control that provides a total of 20dB (±10dB) of variable level, which is useful for making small level adjustments or for compression gain‑compensation.

On Test

Powering up the M103 resulted in a flurry of relay clicks that provided a good excuse to whip the unit's top cover off and take a look inside. With the lid removed, the quality of the engineering within the M103 becomes immediately evident. It uses relays (rated at over 50 million operations) to carry out all switching of audio signals, thus maintaining the shortest possible circuit path and eliminating signal degradation. The circuit layout is exemplary, and the literature describes the low‑inductance ground plane incorporated in their analogue circuit boards to provide stable signal and power‑supply grounds.

The integral power supply intrigued me, as one of its constituent parts is a medical‑grade switching supply, and the whole supply is completely shielded from the audio circuitry by a solid, sheet‑metal wall. This shows that it's perfectly possible to put a universal voltage, switch‑mode power supply inside high‑performance 1U rackmount analogue audio equipment. Hopefully this will start a trend and the dreaded wall‑wart will, one day, be consigned to the dustbin of history.

With the top safely replaced, the M103 turns out to be simple and intuitive to use. Setting it up for use with an AKG C414 large‑diaphragm condenser mic involved little more than switching on phantom power, engaging the 75Hz high‑pass filter to eliminate the low frequency rumble from tapping feet, switching out the EQ and compressor, setting the input level (the peak LED next to the gain control, which illuminates green at ‑10dBu and red at 12dB before clipping, made this a doddle) and setting the output trim to match the input of my mixing console.

The recorded results, on both acoustic guitar and vocals, were exemplary: detailed, dynamic and transparent. Replacing the C414 with a variety of vintage and modern condenser and dynamic mics — and finally with an old TLA large‑diaphragm valve microphone — resulted in recordings that revealed in stark detail the differences in character between each mic. Setting up for a ribbon mic is similarly simple, in that all one has to do is to flip the switch to enter 'ribbon mode' and crank up the gain to suit.

The EQ worked exactly as one would expect. In peak mode, the three‑band sweep EQ with a parametric mid is extremely effective in dealing with anomalies in the basic sound of whatever source is being used. With careful choice of the frequency within each band, it also proved capable of being used creatively, in shaping signals without losing the detail in the overall sound. The high‑ and low‑band shelving responses were also extremely effective in changing the overall character of the source and, with a light touch rather than heavy‑handedness, gave me results that 'tilted' the sound of the source towards or away from bass and/or treble without overpowering it.

If you drive the EQ a bit too enthusiastically — especially if you've put the compressor in front of it — the associated peak LED lights up 6dB before the internal circuitry clips. If that happend, you may need to take a closer look at what you're doing and reduce the EQ and/or compressor gain to compensate.

Personally speaking, I prefer to try to record and mix with as little EQ (and compression) as possible, and the M103 made that process easier, as its transparency meant that I found the effects of slight EQ changes on the unit itself easier to hear — and this meant that my own changes were ultimately smaller.

The compressor was, similarly, both intuitive and a pleasure to use. While it's more than capable of being provoked into pumping by pairing more extreme attack and release times with high compression ratios, when used sensibly and lightly (for example, to gently level vocals) or with more gusto on acoustic guitar or tin whistle, the M103 shows itself to be an extremely transparent and musical‑sounding compressor. Its 3ms minimum attack time means that it is incapable of catching really fast transients, and therefore just cannot take all the life out of a sound — hence its transparency and musicality. The level of gain reduction is displayed on a 10‑segment meter that sits just above the threshold, attack and release controls, to the left of the output VU meter (no peak‑reading LED ladders here!).

Replacing microphones with various transducer‑equipped acoustic guitars, with and without their various preamps, was a revelation. The front‑panel input sounded very good indeed, and running the output of the M103 (either as a DI directly from the mic preamp, or through the EQ and compressor) straight into the mini-PA that is a Jam 400 acoustic amplifier gave me a great sound with virtually every instrument and pickup combination that I could put together; my banjos have never sounded so good. The most stunning result was when I ran my trusty Gurian acoustic guitar, which has a combination of mini-mic and bridgeplate-mounted transducer, through a phantom-powered Pendulum twin‑channel preamp, and plugged that directly into the mic input of the M103.

Finally, I have to mention just how practical I found the audio I/O connections on the M103 to be. A mic input on XLR and an instrument input on quarter‑inch jack in a channel strip could be expected. Finding a rear‑panel, completely independent mic preamp out on both balanced XLR and unbalanced jack was an unexpected bonus that allowed me to go straight to a DAW, a recorder, a console or an amplifier. Again, a line input and main (post EQ/compressor) output on XLR could be regarded as standard — but separate unbalanced and balanced outputs are not exactly common in my experience.


As you may have realised already, I've been very impressed by the Grace Design M103 channel strip. The engineering‑led approach that, from my point of view, characterises the Grace product line accords completely with my own philosophy and approach to audio. Subjectively, the sound quality proved to be exactly what I'd expect from a Grace Design product: dynamic, transparent, musical and very revealing of its sources.

Whether this sonic character will suit everyone all of the time is, of course, another matter entirely. Some people look for absolute sonic accuracy in their recording gear, while others will only countenance the warmth of transformer or valve‑based equipment. Yet others (such as myself) prefer to have a bit of everything available in their arsenal.

Operationally, I found it impossible to fault the M103. Setting up the unit is extremely intuitive, as its controls are well laid-out, logical and extremely responsive in use. The various I/O options mean that the M103 can be integrated into virtually any situation, from being simply a voice channel in a studio or live environment, to acting as the heart of a live acoustic or electric instrument setup.

Form, function and build quality are all exemplary and these, coupled with its very high level of sonic performance, make the M103 a very capable and desirable unit indeed.  


Around this price point you'll find other, functionally similar units that you might want to audition, each of which will have its own distinctive feature set and sound. My suggestions would include Focusrite's ISA 430 MkII and their Liquid Channel, TL Audio's 5052, SPL's Frontliner and the Universal Audio LA610 MkII.

Published March 2011