REDGUM RGi120ENR Integrated Amplifier


"Audio Magazine", Russia, (p96-100) No. 5, Oct 2010


Magazine Cover



http://redgum.concert-audio.ru/pdf/redgum_rgi120enr.pdf  - (Includes pictures...)

Translation by Google; edited by L.G. (REDGUM Audio P/L)




For the first time on our test bench, a guest from exotic Australia. The company, Redgum Audio, is located in the state of Victoria, the cool southern part of the continent.


Red Gum - the pride of Australia, this pink (sic) eucalyptus is part of its unique flora. The bark of this tree produces a valuable sticky sap used in medicine and technology.


The research and business director of the company is Ian Robinson. Born in 1947, he has come a long way from being a retailer of leading audio equipment to a professional Australian designer, with research governing his designs and production of audio equipment since 1972. A quarter-century on, by 1998, Redgum amplifiers had had major international success in the global audio market. And after 12 more years of continuous and systematic upgrading of the amplifiers, we finally have a current Redgum RGi ENR 120 (sic) to assess and audition.

Concept and Design


The modern development of musical aesthetics, its diversity of genres with countless ways of creating and transmiting artistic images created by composers and performers, along with atonal harmony, dissonant sound combinations, high instantaneous volume levels ... all of this has caused a growing cult of audiophiles and music lovers around the world and demanded a radical revision of audio concepts, with the deliberate rejection of old but popular traditions. This is achieved efficiently and optimally in the designs of Ian Robinson.


This is his basic philosophy, as realized in the Redgum RGi 120 ENR amplifier:
1. The output stages use only high-field-effect transistors (MOSFETs) as they are able to optimally transmit high leading- and trailing-edges of powerful current pulses, which provide good signal macrodynamics (large amplitudes), and high linearity at low amplitudes (microdynamics). In the test unit a total of four complementary pairs of 20N20/20P20 are installed, manufactured by Exicon (200 V/16 A/250 W).


Any valves? An emphatic "no", as true tube circuits cannot provide the required peak power. And, in addition, to match the impedance of dynamic speakers, they require an output transformer where the signal passes through the length of the primary winding and is then induced through a nonlinear magnetic core to the secondary, the output winding, "resting" at the top end in the inevitable leakage inductance between them, which causes both the frequency and phase distortion of valve amps.


2. A high-low impedance power supply (Ed. named UltraFlex) providing a leading edge signal at maximum capacity, and with deep silence between signals. In this unit, the power supply is based on a toroidal transformer of 500 VA and a pair of capacitors (10,000 uF).


3. Selection and inspection of electrical components and individual parts for each sample. Manual assembly and installation using a special silver solder with flux, eliminating the usual foaming of soldering and provides durable properties once installed.


4. The use of two independent volume controls per channel with "ribbon" contacts, ensuring high reliability and, if necessary, a good electrical balance of channels without the use of a conventional third regulator which usually deteriorates the sound quality. The volume and balance can be controlled by the remote control supplied.


5. Protection against overload when exposed to external factors, and also in the event of internal noise.


6. Rejection of in-built phono stages. Sound reproduction requires a high quality phono amplifier, which can be installed either in the housing of the record-player, or close to it. Since the signal from a high-quality cartridge is very low, it is subject to significant distortions in the interconnect. In addition, an in-built phono amp is not always required, and this additional cost can limit the demand for an amplifier.


7. For vinyl lovers wishing to become familiar with the sound character of this dual mono amplifier , they will need to add a separate phonostage, Redgum's RGPH2.


8. For effective cooling of the high-power output stages of the amplifier, an all-aluminum heatsink is used featuring a special curved shape that forms the entire base of the amplifier.


The front panel of the unit, 20mm thick, is made of this pink eucalyptus. On the left is an elegant keyhole for a special key, that turns on the power. On the right are the two volume knobs, and next to them is a fixed ?knob?, which displays power and choice of input.

.
The amplifier is controlled by a handy miniature remote control for both amplifier and CD-player functions.

Audition

At the first session, we heard nice inclusions for many coveted crystal-clear, crisp, like transistors' sound, but with an unexpected spirituality, breathtakingly soulful musicality not normally inherent in standard transistor amplifiers. Often, for the sake of musicality and subjectively perceived vividness, we forgive tube amplifiers for being too soft and lethargic, and transistor amplifiers driving active speakers, forgiving their rough and somewhat dry laconic tonalities. Here, the sound of the Redgum RGi 120 ENR, had the complete lack of transistor roughness, everything was "smooth" and a laconic sense that only promoted its amazing musical expression. Due to the extremely low frequency range (0.8 Hz) and almost zero output impedance, it reproduced the lower registers superbly with a complete lack of transitional distortion. Perhaps, if we did hear some transistor characteristics, they did not cause the slightest discomfort. No rough sound, no "grit", which typifies most transistor amplifiers was observed the closer you listened to this amplifier whether from CDs or LPs.


Elegant, exciting energy with amazing amplitude, penetrating, stunning macrodynamics and simultaneously bottomless depths of clear, noiseless pauses at very high volume levels - we have not met such an amplifier like this before. We heard for the first time the real sound "barrage" of Chinese drums (7, track 10) and felt the tragedy of the tocsin alarm bells deeply (9, track 22). Ridiculously surprising, it was at the sound of a closing garage door (9, track 20) that we all shuddered, not having done so on previous occasions. So that is how it sounded.


Now specifically about the music.


Let's start with Pierre Boulez, for his brilliant interpretation. Even normally "The hammer without a master" was an expressive musical instrument (4) as we had found when listening in the past, but this time were deeply convinced of it.


"Alpine Symphony" by Richard Strauss gave us an amazing panoramic view of the mountain sunrise (3). Only with the 120 RGi ENR (sic) did we feel all the pathetic nervous tics and jerks of the guitar strings in the playing of "Lord's Tundra" (8 Track 9).


Without planning to, I am giving fragmentary references to the tracks. Usually we do not abuse this, limiting comments to only a generalized description of the properties of sound reproduction. But the RGi ENR 120 amplifier sounds great, though in its own particular way!


Today we enjoy music such as Pierre Boulez's, but if Tchaikovsky heard it, he would not believe that this would ever be called music, and even more so. ? brilliant.


Listening to this extraordinary amplifier, we were interested to see how the various components of tube or transistor sources affect the overall character of the sound. To do this while listening to a CD, we used two CD-players - Holfi Xara NFB (transistor) and LUA Cantilena Mk II Midi (tube), and to play the records - phono stages: transistor Dynavector P-75 and the tube Ear / Yoshino 834P DeLuxe. Here, when listening to various genres and instrumental compositions and soundtracks, both analog and digital, tube technology is clearly recognizable, but the musicality remains virtually unchanged. Having a preference for either source has been difficult.

Summary


The RGi120ENR successfully masked the deficiencies (if they were any) of other components. Many thanks to the company, Redgum Audio, and of course Ian Robinson for the true pleasure which they gave to us with the help of their technical masterpiece. There is no doubt that the Redgum amplifier is able to charm modern audiophiles. But it is advisable for lovers of music of "the old school", admirers of single-ended amplifiers, to have a preliminary listening.

 

Redgum RGi 120 ENR Integrated amplifier

TECHNICAL SPECIFICATIONS

Output power of 155 + 155 W / channel RMS
Peak 293 + 293 W / channel WRMS
Harmonic Distortion 0.009%
Intermodulation distortion is less than 0.005%
S / N ratio greater than 100 dB
Input impedance 10 ohms
Frequency range of 0.8 Hz - 80 kHz (-3 dB)
Peak current greater than 150 A
Dimensions 420 x 360 x 93 mm
Weight 18 kg

EQUIPMENT LIST

CD players LUA Cantilena Mk II Midi, Holfi Xara NFB;
Turntable Thorens TD 320 Mk II;
Phono stages Dynavector P-75, Ear / Yoshino 834P DeLuxe;
Cartridge Sumiko Celebration Pearwood Signature (MC);
Speakers Chario Constellation Pegasus;
Interconnects Audio Quest Python;
Cables to the AC XLO Electric Signature 2 Type 5.2;
Network cables Fisch Audiotechnik Performance-3, IsoTek Optimum.

MUSIC

Records
1. Test Record 1: Depth of image, Opus 3
2. Test Record 2: Timbre, Opus 3.
3. Richard Strauss. Alpine Symphony (EMI Records, ASD 1435771)
4. Pierre Boulez. Le marteau sans maître (CBS, 76191)
5. Witches' Brew (Living Stereo, RCA Victor, LSC-2225)

CD

6. Burmester Audiosysteme Vorführungs-CD II
7. Burmester Audiosysteme Vorführungs-CD III
8. Stereophile Test CD3 (STPH 006-2)
9. Musique Ouverture de l'esprit invitation au voyage au rêve (Triangle Electroacoustique, CD de demonstration 2003-2004)