Gryphon DM100 Dual Mono Amplifier Reviewed

Published On: February 14, 1992
Last Updated on: October 31, 2020
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Gryphon DM100 Dual Mono Amplifier Reviewed

When "big" amps aren't enough, there's the DM100 dual mono from Gryphon. It's 168 pounds of 100-watt Class A amazingness. It's bigger than some coffee tables, and it will blow you away (in a good way, of course).

Gryphon DM100 Dual Mono Amplifier Reviewed

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Ever fall in love at first sight? With a human being, a car, an article of clothing? Doesn't happen often (thank goodness), but when it does -- whoa. Hi-fi, too, has its share of drop-dead gorgeous, I-just-gotta-have-it hardware, and you're all forgiven for lusting after a component not because it ushers the voices of angels into your rooms but because it might cause a quiver in your loins. What the heck -- different strokes for different folks. And just as the British makers go out of their way to plumb even greater depths of ugliness, so do the Danes strive for even greater beauty in what are, after all, nothing more than metal boxes filled with bits of wire. B&O survives almost entirely on looks, Primare is the Gaultier of audio, while Gryphon is, well, Bauhaus in your haus.

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What started with a pocket-sized line pre-amp and phono amp has developed into a range of power amplifiers and pre-amps which should be sold in Chaumet rather than a hi-fi shop. Flemming Rasmussen, despite looking like a prop forward for the London Welsh, oozes taste and style. He insists that his products please the eye as well as the ear and has endowed Gryphon with a persona which implies a marriage of art and technology, form and function. Even his mains leads are chic. His most recent challenge? To turn a monster of a power amplifier into something almost svelte. Which isn't the first word that comes to mind when describing a 100W/channel, pure Class A stereo amplifier weighing 76.5kg and measuring 56x25x62cm (WDH).

So how do you transform something this bulky into an objet d'art? Black seems to be Flemming's fave colour, so the DM100 Dual Mono Amplifier is pure Spinal Tap. It's layered and sectioned like a Sassoon cut, metal chassis and acrylic front panel, ankle-slicing heat sinks -- it's almost an optical illusion. When sitting on the floor unpowered, the DM100 looks merely sinister, a sleeping beast but a space-stealer you can't ignore. Yet it doesn't shout 'high tech' or even 'hi-fi'. Switch it on via the sole feature on the front panel, a rotary control sporting a triangle, and red illumination creates a satanic leer. You expect it to rumble, shake its haunches and leap at your throat, the 'dog' in Ghostbusters come to life. But it doesn't. It just sits there looking mean and moody.

The back contains what amounts to clutter in the the Gryphon lexicon. A fan port, large custom-made gold plated terminals, balanced (XLR) inputs (no single-ended option), a fuse holder, the main AC switch (the front selector chooses 'off' or 'standby') and 'Bias adjustment'. This last-named rotary selector allows you to 'dial in' the amount of Class A, with 100% being pure Class A into an 8 ohm load. The more efficient the speaker, the less Class A is required (eg, to lower AC power consumption), so horns might be run with the control at 50%. (As I did all of my listening with Apogees and Sonus Faber Extremas, I left it in egg-frying mode.) Underneath the unit is a toggle which is set for AC mains with or without true (pole in the ground) earthing.

Take off the lid and it's just as pretty and 'super-detailed'. The section nearest the fascia contains the transformer and rectifier stages. A pair of custom-made 1200W toroidals reside here, sheathed in a resonance damping, shielded enclosure. This is connected via eight high-current bridge rectifiers (four per channel), hard-wired to a massive bank of 48,000 uf RIFA capacitors flanked by the driver sections. At the back, there's an AC input filter to remove RF and HF noise, the driver stages (with a dedicated 20,000 uf capacitor bank) and the output devices. Special capacitors on separate PCBs take care of the input section, mounted next to the wholly justifiable chunks of heat sink. I didn't have a thermometer to hand, but the DM100 may be the hottest-running tranny amp I've used.

The DM100 also features protection circuitry in the form of integrated circuits free of relays in the ouput stages. If DC or HF is detected at the input, a monitor will cause the unit to mute. Another circuit monitoring the difference between input and output will trip internal (non-user-replaceable) fuses, while a thermal sensor will activate a circuit breaker if the amp overheats. Needless to say, I didn't witness any of these devices in action, despite attempts at knocking Deep Purple out of the Guinness Book of Records. Nothing, and I mean nothing, upset this amp. Which is nice to know when you've shelled out £7300 for a piece of hi-fi equipment.

Other circuit details adhering to the Rasmussen School of Amp design include ultra-short signal paths, minimal negative fedback, a non-magnetic chassis and no-compromise parts quality. Solid copper buss-bars and heavy guage wire are employed to feed the power to the output and gain stages, while the driver sections, fed from separate windings on the transformer's secondary side, are directly connected to the output boards.

Switch-on is drama-free, but an excruciatingly slow warm-up period will lead you to leaving the primary power on at all times (the button at the back), using the front-mounted control to take it out of stand-by mode. From ice-cold, the amp needed five or six hours to reach the heights; from stand-by, under 10 minutes. A slow-start circuit prevents your lights from dimming.

Read more about the performance of the DM100 on Page 2.


Acoustic Energy also supplied Gryphon's least expensive pre-amp, the Gryphon Linestage, an 'entry level' alternative to the Preamp and the LX. This, too, is all-black and dual-mono, the latter carried through to two external power supplies with individual mains leads. Volume is controlled through a pair of 24-step attenuators using fixed-resistor networks. The separate left/right source selectors choose between mute, DAT, CD, Tuner, Tape and Auxiliary. Front panel lighting to indicate 'on' consists of a row of tiny fibre optic 'strings' instead of LEDs. All connectors are gold plated, and two sets of outputs allow for easy bi-amping. The review sample had XLR outputs which I was told are not truly balanced but would enable me to run the DM100 with XLR-terminated leads. I also used the Classé DR-4 pre-amp which does provide full balanced operation.

The Linestage sounded so much like the Preamp that I couldn't really understand what, other than aesthetics, justified the tariff over the Linestage's 2500. It took a couple of weeks, but -- eventually -- the dearer Gryphon did prove to be a touch more precise, especially in its retrieval of spatial characteristics, and it possessed greater dynamics, especially in terms of 'protecting' low level information. The latter, no doubt, helped to create the more convincing and accurate soundstage. The differences, though, were barely significant and it took a lot of ear-to-the-grille listening before I felt that I could identify either in a police line-up.
The DM100, though, produced (like Counterpoint's Natural Progression) an altogether more 'elusive' sound. However overpowering its presence, however strong its image, sonically the Gryphon had a chameleon-like quality which forced me to try a greater variety of speakers, source material and speaker cables than are usually required. Convinced that (after a week of straight cooking) the Gryphon was working up to par and spending equal time with both the Gryphon Linestage and the Classé DR-4 pre-amp, I thought I had the amp down pat. But moving from Extrema to Stage to Diva to WATT/Puppies to AR M1s brought about changes which I could not attribute to the speakers -- all of which I know as well as the keyboard to my computer. All have strong, readily identifiable sonic signatures. All have predictable characteristics which determine whether or not they like tubes, trannies, Class-A, MOSFETs, whatever. They, or something in the chain, were acting strangely.

The Gryphon, while producing through every speaker a marvellously solid, palpable, fat-free sound, could turn dark, as dark as its faceplate. Not congested, not muddy, not lacking in transparency, but, well, dark. It was almost entirely a function of the lower registers, which tended to dominate on all but the smaller systems. And that's because the smaller systems shave off the bottom octaves. Here was a ludicrous situation typical of the confusion I experienced: I preferred the WATTs sans Puppies when driven by the DM100, the Stages to the Divas. However open and clear and fast -- and I mean lightning-quick -- the sound from the lower midband on up, the bottom octaves had a density and weight which could tend toward the overpowering. Ameliorated by speaker cable selection, thinner cables almost acting like filters, I could tame the slight boom and lift the sound, but I couldn't help wishing I was a Rastafarian.

This bass prominence proved a might disturbing because the rest of the sound is so authoritative, controlled and -- above all -- balanced. The character is pure Gryphon, pure solid-state, a perfect mate for the dearer Preamp. If ever an amp sounded like a clone of a pre-amp, the DM100's relationship to the Preamp is pure doppelganger. What you hear when you swap to the Linestage, as described above, is a slightly weaker version of the Preamp, but there's no mistaking the Gryphon DNA chain. If anything, the Gryphon sound is so naked, so unforgiving, that some might find either unit to be better mated to a softer unit, the Classé with the DM100, for example, or the Linestage driving a tube amp.

But this is Gryphon/Gryphon, and what you're left with is true high end performance -- lush and sweet and quick and powerful -- but with a major matching proviso. The bass freaks among you (the ones who wish that loudness buttons and tone controls had street cred) can ignore my caveats. For the rest, you have to audition this amp not just with the speakers you'll be using but in the very room you'll be using. On the other hand, just one look may have you reaching for your Amex....

Additional Resources
• Read more stereo amplifier reviews from
• Find an AV receiver to integrate with the amp.
• Discuss audiophile equipment on

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