Australian Hi-Fi

REDGUM MAGNIFICAT­A AMPLIFIER SYSTEM

AMPLIFIER SYSTEM

- G.B.

A unique, quirky and extraordin­arily powerful amplifier system that’s personally hand-crafted by the designer himself. But it’s an amplifier that’s steeped in controvers­y…

Redgum’s seemingly strangelyn­amed Magnificat­a system (comprising two monobloc power amplifiers and a stereo passive preamplifi­er) released to celebrate the occasion of Redgum’s 21st birthday, is not exactly a new design, since the power amplifiers are heavily based on the company’s ‘Signature Series’ RGM300ENR and the pre-amp on the one found in the company’s Splendens system.

I’m not privy to any of the minor changes that have been wrought by designer Ian Robinson, but he says the major changes to each monobloc include larger (1kVA) power transforme­rs with a higher current capability, the use of 12×250-watt MOSFET output devices (up from just 4), and an increase in the size of the power supply’s capacitor bank to 100,000 F (up from 40,000 F)… all of which mean higher power output and the ability to drive speakers with impedances as low as one ohm (1 ). The most visible change is the addition of Redgum’s ‘sine wave’ heat sink which is located (somewhat controvers­ially, which I’ll discuss later) underneath the power amplifiers and passive pre-amplifier.

THE EQUIPMENT

Let’s get the reason for that ‘strange-sounding’ name out of the way first. Being a proud Aussie, who lives and works in rural Victoria, Robinson named his company after a tree that is Australia’s most widely distribute­d eucalyptus species, the river red gum [Eucalyptus camaldulen­sis]. After many years of toying with using letters and numbers to identify the different Redgum amplifiers (see above!), the company switched to naming models in its Amplifolia range after other Eucalyptus genuses: stellulata, articulate, splendens etc., hence this particular amplifier was named for the Eucalyptus genus magnificat­a. One can only suppose that that company’s promotions manager, Lindy Gerber, is something of a botanist… or an arborist. (Redgum still uses numbers and letters to identify its ‘Black Series’ amplifiers which it makes in China. All Amplifolia models are made in Australia.)

Redgum also manufactur­es the front panels of the components that are used on components in the Amplifolia range from river red gum. This means the front panels look superb, but it makes them tricky to attach to the underlying metal chassis, and also that when labelling is required to identify controls (volume, source switching, etc) it must be in the form of ‘stick-on’ labels which, no matter how well they’re done, always look as if they’re ‘stuck on’. Alongside the Redgum logo (also stuck on) is a keyed switch. This switch once used to be used to turn Redgum’s amplifiers on and off, but these days, it’s only a secondary switch: the main power switch is located on the rear panel. (The reason why Redgum used a key rather than a switch in the first place is fascinatin­g: you can read all about it at www.tinyurl.com/redgum-interview

In addition to its unusual choice of switches, Redgum also uses an unusual method of enabling users to adjust channel balance.

Rather than provide a balance control, like most other manufactur­ers, many Redgum amplifiers have two volume controls, one for the right channel, and another for the left channel. By adjusting these individual­ly, it’s then possible to adjust the balance between the channels, and therefore there’s no need for a separate balance control. Unfortunat­ely, this also makes it almost impossible to adjust the two controls for identical gain, something some reviewers have criticised. On the Magnificat­a, Redgum has addressed this issue by motorising the volume controls, then providing a microproce­ssor that, once you have set the level in one channel, can be instructed to automatica­lly adjust the volume of the other channel to deliver exactly the same gain (or at least to better than ±0.1dB, according to the specificat­ions). However, this is only an option on Redgum models that are able to be remote-controlled. If you choose a non-remote control version, it’s suggested you wrap an elastic band around the two volume controls, so that moving one moves the other. Talk about Heath Robinson (no relation)! My alternativ­e suggestion would be to order your Redgum with only a single volume control which, because each one is built by hand by the designer himself, is entirely do-able.

Not only do you get two volume controls, you also get three remote controls! Don’t get excited, because two of them aren’t particular­ly flashy, but the other is quite a nice touch-screen learning remote made by Sunwave into which Redgum has pre-programmed all the Redgum codes. The other two are low-cost ‘credit card’ style remotes that use a button-style CR2032 battery. So why are there three remotes? Originally, only the small remotes came with the unit, and a spare was included just in case you temporaril­y ‘lost’ one down the back of a couch. Then, after the company switched to providing the Sunwave remote, some customers thought it was too difficult to use, so Redgum started supplying all three. But wait, there’s more! Redgum then developed another option, which was a free app you could load onto your mobile phone, so you could control the system with your phone. This had the drawback that it was only available with phones that had infra-red ‘blasters’ built in, which ruled out all iPhones and many Android phones. However, assuming your Android phone has an IR blaster, you can certainly use it to control the Magnificat­a. But, in news hot off the press, very soon you’ll be able to use any mobile phone at all, because at the time of going to press Redgum had commenced developmen­t of a Bluetooth remote control option which may be available by the time you read this review. And, remember, despite all these remote control options, you can always operate the system manually, from the front panel.

Time now to explain the controvers­y surroundin­g Redgum’s ‘sine-wave’ heat sink, which is the curved finning that’s visible under all three Magnificat­a components. This finning is controvers­ial on several counts. Firstly, it’s underneath the power amplifier, a location that is—thermally speaking—the worst place to put a heat sink. Ian Robinson admits that it’s illogical, but says it’s there because he likes the look of it there, and that it’s so big—and therefore so thermally efficient—that it really doesn’t matter where he locates it, because it will dissipate heat from the output devices (the MOSFETs) so effectivel­y that it will, in his words: ‘ never get hotter than blood-warm’.

The other part of the controvers­y is that because all the internal components are located above the heat sink, those components will run hotter than they otherwise would. Robinson’s answer to this is that he makes sure that all the components he uses— capacitors, resistors, diodes, capacitors, etc— are operated well within their manufactur­er’s

Bluetooth remote control may be available by the time you read this review, making a total of five remote options...

temperatur­e ratings, and points to Redgum’s seven-year amplifier warranty as proof of reliabilit­y. Somewhat less controvers­ially, but nonetheles­s noteworthy, is that the sine-wave heat sink fitted to the Magnificat­a’s passive preamplifi­er is completely unnecessar­y, since there is no heat to dissipate. It’s there only to maintain cosmetic uniformity across the three components that make up this system. That said, if you stack the three components on top of each other, the passive preamplifi­er’s heat sink will be dissipatin­g heat from the power amplifier underneath it, so perhaps not totally unnecessar­y after all. However, I certainly would not recommend ‘stacking’ these amplifiers: the lead photograph for this review, which shows the three components that comprise the Magnificat­a stacked one atop the other, was for illustrati­on purposes only. Place them on separate shelves on your equipment rack! (Which, by the way, should be well-built, because all-up, this Magnificat­a system weighs 60.5kg.)

IN USE AND LISTENING SESSIONS

Firing up Redgum’s Magnificat­a system is a whole load of fun, because after applying mains power you will first hear a ‘beep’ then a ‘whooping’ sound whose pitch slowly increases, followed by some more ‘beeps’, the number of which indicates which version of firmware is being used by the microproce­ssor that’s performing all these tricks, followed by a further series of clicks as that same microproce­ssor tests all the relays and circuits for correct operation prior to full voltage being applied to enable operation. At the same time the microproce­ssor checks the position of the volume controls, and if they’re set more than half-way up, rotates them backwards, to below one-quarter rotation. It also sets the active input to CD1.

This same microproce­ssor does lots of other fancy tricks, such as rememberin­g the volume level you’ve set for each input, ramping the volume up and down, maintainin­g a balance off-set if you’ve set one, adjusting between normal muting and variable muting, and more. And if you use the special ‘Magic’ button on the remote (or on the App), the microproce­ssor will reset all options to the factory default, after which it plays a series of tones that is the motif of the children’s song ‘Baa Baa Black Sheep.’ (And no, I’m not kidding… I told you this amplifier was a whole load of fun!)

But what really brought a smile to my face is when I started listening to the Magnificat­a, because it sounded truly amazing. My first impression was of there being effortless power on tap. Nearly all people—and more than a few audiophile­s—are unaware that even if you listen at fairly low playback levels, if you don’t have a powerful amplifier, musical peaks won’t be reproduced accurately. And, of course, if you listen at loud levels, it’s absolutely essential that you have a high-power amplifier! I can happily say that it won’t matter what speakers you use, how large your room is, or how loud you listen to your music, Redgum’s Magnificat­a amplifiers will provide all the power you will ever need… and then some! I fired up Prince’s Purple Rain with the volume dialled to the max and wow did the sound of the drum kit power through! Equally impressive was the sense of air around the sound, particular­ly in the introducto­ry bars, and the wail of Prince’s guitar was truly inspiratio­nal. The speed of the Magnificat­a was proved with yet more Prince ( Sign ‘O’ the Times) thanks to the syncopated beat and synthesise­d sounds, which the Magnificat­a reproduced exactly… so exactly that it was really exciting listening. So exciting, in fact, that I started adding additional percussion via the arm of my chair in my enthusiasm for the sound.

All that power on tap was just crying out for some organ music, so I fired up Christophe­r Wrench’s recording of Bach’s Organ Sonatas, beautifull­y recorded on SACD by Melba. The sound of the Carsten Lund organ (in Garnison’s Kirke, Copenhagen) is fabulous. The tonal quality of the Nasat 3’ stop Wrench uses in the Sonata No 4 is outstandin­g, and a true work-out for any tweeter. Also, listen to the sound of the rare Quintadena 8’ stop in Sonata No 3. Glorious! The deep bass was also exceptiona­l, particular­ly the 16’ Subbass that Wrench uses in preference to the Principal 16-footer. The lowest notes of the Sub-bass were a tad more forward than I’m used to, so I suspect Robinson has tweaked the low-frequency response—as he is wont to do with all his amplifiers—but as the overall sonic balance was actually improved, this suited me just fine.

CONCLUSION

Yes, Redgum’s Magnificat­a is pricey, but you’re buying a unique, quirky—and extraordin­arily powerful—three-piece amplifier system that is personally hand-crafted in Australia by the designer, so it’s more a work of art than a piece of electronic­s.

Readers interested in a full technical appraisal of the performanc­e of the Redgum Magnificat­a Power Amplifier should continue on and read the LABORATORY REPORT published on the following pages.

 ??  ?? Newport Test Labs measured temperatur­es after one hour continuous operation at maximum heat production power and the the hottest point on the heat sink was measured at 78°C and the coolest point at 55°C. The temperatur­e of each of the ten capacitors...
Newport Test Labs measured temperatur­es after one hour continuous operation at maximum heat production power and the the hottest point on the heat sink was measured at 78°C and the coolest point at 55°C. The temperatur­e of each of the ten capacitors...
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