ONIX - OA21S
class A integrated amplifier
British designs of integrated amplifiers belong to the most numerous group of valued audio devices. The British company Onix, which is not very popular on the European market, fits perfectly into this group. The devices are built very solidly, and their visual style resembles the current Cyrus ONE amplifiers. The OA21S is a small 90s integrated amplifier armed with a solid toroidal transformer that delivers powerful, dynamic sound with 50 watts per channel in Class A.
The amplifier is based on a simple design, which was probably inspired by the legendary Mission amplifier. The use of high-performance silicon power transistors MJ15004 GE/RCA generates a huge power that the amplifier has. The construction is based on discrete elements, supported by 4 capacitors with a total capacity of 18,800 uF. (4x4700uF). The whole is mounted on a good quality PCB, where a separate element subject to simple replacement is the Moving Magnet (MM) phono preamplifier. Onix is based on loudspeaker terminals known from the Naim design, whose holes accept only banana plugs. At the top above the gold-plated RCA inputs we find an unusual 5-pin connector for an external SOAP power supply, which is available as an optional add-on unit.
Plugging in an additional external SOAP power supply significantly increases the power with which the above-mentioned Onix amplifier copes well. The external SOAP will provide additional isolated power to the amplifier with the support of 44,000 uF capacitors, which will provide more pure sound without distortion. The front of the device is made of a fairly thick anodized aluminum panel. The appearance is quite minimalistic, between the symmetrically placed input / output selector and the volume control (blue ALPS) there is the main power switch of the device. The operating status of the amplifier is signaled by a red diode located under a small rotary switch located in the middle. The whole is accompanied by a neat, well-fitted housing. The side walls together with the upper part of the casing constitute one element, which additionally stiffen the entire structure by sliding the assembly from the back. The amplifier does not support remote control with a remote control.
Sound
Onix-OA21S, despite the low declared book power, can boast of a muscular dynamic, dynamically exposed sound. The power presented by the OA21S enclosed in a neat housing can be an indicator of a well-designed amplifier that will not be afraid of modern, efficient designs. The bass that Onix presents is tight and firm, boldly accentuating the rhythm of the kick drums with the bass guitar. The snare drum beats are juicy and lively, where with proper filling we listen to how the trembling membrane gives the rhythm a military chic. The guitars have a strong overtone with a sweetish tint, and the male vocals do not lack anything. Mass and strength with the right complement of the warm-sounding Onix impresses from the first sounds we play on it. A spoonful of tar in a barrel of honey may turn out to be soprano, which is not the strongest point presented by the amplifier. The treble is slightly withdrawn and does not deliver the exciting cymbal sounds that the Naim or even the Pioneer can boast of. You can't say that they are bad, overblown, metallic or flashy, but they certainly lack vigor and sparkling complement. The warm, muscular style that Onix plays can significantly withdraw some of the keyboard instruments, and the purity of the delicate female vocals.
Conclusion
It's hard to find major flaws in the warm-sounding timbre served by Onix. High frequencies, which cause the greatest difficulties for the above-mentioned Onix amplifier, can be eliminated by proper cable selection. I regret that during the tests of the amplifier I did not have the Audiomica Excellence series cables, which could significantly improve the shortcomings of the already good-sounding Onix.
Technical data:
Class: A
Power: 50W per channel
Construction: based on discrete elements
Inputs: 5x gold-plated RCA (for VCR, TAPE, CD, TUNER and MM)
Outputs: 1x gold-plated TAPE OUT
Additional ground GND input for turntable
Additional inputs: 5-pin input for additional SOAP power
Speaker terminals: accepting only 4mm banana plugs
Libra: 5.1 kg
Dimensions: width 230mm, depth 370mm, height 75mm
Color: Black
Prepared by: Łabędź Przemysław