Arcam Delta 90 amplifier

Good hi-fi equipment is much more than just a set of highly impressive technical specifications; the listening quality is more important than any set of figures. A&R's Delta Series of audiophile components has been designed to combine modern aesthetics with A&R's proven ability in electronics, to produce a matched range of equipment that will satisfy even the most critical music lover. The first product in this stylish new generation is the Arcam Delta 90 intergated stereo amplifier. This combines great functional flexibility with good looks and a tremendous dynamic range seldom found in equipment at this price level. The use of the highest quality components, such as 1% metal film resistors and polypropylene capacitors, ensures a notably clean and beautifully natural sound quality up to and beyond the amplifier's rated 70 watts per channel.

 

The Delta 90 can accept inputs from both moving magnet and moving coil cartridges, selected using a switch on the back panel. Moving magnet cartridges can be optimally matched by the addition of a switchable internal loading module, type ULM/M. additionally the Delta 90 can accept inputs from CD, tuner and two tape recorders - all four inputs having high overload margins to enable any source to be accepted without distortion. There are independent controls for both "listen" and "record" functions, allowing the user to listen to one programme at the same time as recording another from an entirely separate source. The bass and treble controls have been designed so that deficiencies in samll loudspaekers and cartridges may be corrected without affecting the critical midrange. For the ultimate in audiophile sound these controls may be bypassed with the "direct" switch on the front panel' nevertheless, used sensibily they can help correct for many imperfections that may be present elsewhere in the audio system. All input sockets are via high quality phono sockets. The loudspeakers are connected using heavy duty posts which will accept any type of connector;4 mm plugs, spade, pin connectors. Although the main speaker sockets are wired directly to the amplifier outputs (to obtain the best possible sound quality), a second pair of switched outputs is also provided enabling the loudspeakers to be cut out when using headphones. Two tape recording outputs are provided allowing full tape to tape dubbing as well as the ability to listen to a different source (from the one that is being recorded) by using the "listen" control.

 

Power

The amplifier section of the Delta 90 will drive any real loudspeaker load, for great care has been taken to ensure that power output and current delivery is maintained into low impedance and reactive loads. The amplifier's high current capability is made possible by the use of superior quality MJ15003/4 complementary power transistors fed from high value, low ESR reservoir capacitors and a generously rated toroidal mains transformer.

In order to maintain the highest standards of fidelity, no fuses are used in the loudspeaker outputs or the DC supply lines. Instead, the Delta 90 is protected against overload and abouse by a quick acting electronic protection system. In addition to this, a pair of heavy duty relays serve to protect the user's loudspeaker system; these will mute the output at switch-on and in the unlikely event of a malfunction in the Delta 90 's power amplifier stages.

 

Styling, quality and reliability

The Delta 90 uses custom high quality aluminium extrusions for cool running and to produce a strikingly elegant case that will grace any home both aesthetically and musically. Styled in conjunction with a top industrial designer the Arcam Delta looks as good as it sounds.

Great care has been taken in every aspect of the design, which was only finalised after intensive listening tests. Internal wiring, apart from connections to the transformer, is almost eliminated by the use of a single fibreglass printed circuit board. Every amplifier is rigorously checked at all stages of production and great pride and care is taken in its construction and appearance. All testing is carried out using advanced computer controlled ATE (automatic testing equipment). Finally each amplifier is burnt in and retested before final inspection, packing and despatch in order to ensure a long and trouble free life.

 

"From the outset the amplifier showed itself capable of a very soild dynamic performance. It also took and kept a grip on the subtleties of the stereo signal. The amp looks well set for as long and honourable a life on the hi-fi market as the A60 has had"

 

Specifications

Output Power (both channels into 8 Ω , 20 Hz - 20 kHz, 0,5% T.H.D.):  70 W

Single Channel (into 8 Ω ):  typically 85 W

Single Channel (into 4 Ω ) :  typically 130 W

Peak Current Deliver:  ±16 A

Total Harmonic Distortion:  0,02% (60 W, 8 Ω  at 1 kHz)

Frequency Response

Disc :  better than +0,3 -0,5 from 40 Hz - 20 kHz (typically -3 dB at 20 Hz)

Line :  ±0,5 dB 20 Hz - 20 kHz (typically -3 dB at 8 Hz - 50 kHz)

Tone Controls:  ±6 dB maximum at 20 Hz, 20 kHz (fully bypassable)

Crosstalk:  65 dB at 1khz (all inputs)

Inputs Sensitivity/Impedance

Disc :  2 mV/ 47 k Ω  /100 pF

Noise CCIR :  73 dB

Overload Margin:  at 1 kHz is 38 dB

Switchable universal loading module (ULM/M) available provides: 30 k Ω , 8 k Ω  200 pF, 320 pF, 420 pF and user programmable option.

Disc (Moving Coil)

100 µV/330 Ω

Noise CCIR :  -66 dB

Overload Margin :  at 1 kHz is 38 dB

Tuner, Tape 1, 2 :  100 mV/20 k Ω 

Noise CCIR (ref. 1 W output) :  -77 dB

Overload Margin :  at 1 kHz is 50 dB

CD :  220 mV/6 k Ω

Noise CCIR :  -77 dB

Overload Margin :  at 1 kHz is 50 dB

Outputs Level / Impedance

Tuner, Tape 1, 2 : 100 mV (nominal)/3 k Ω 

Headphones Impedance :  Suitable for headphones of 80 0hm to 2 k Ω 

General

Power Supply:  240 V nominal ( adjusted to 220 V, 120 V and 110 V nominal)

Power Consumption:  300 VA

Dimensions (W x H x D):  430 x 90 x 265 mm

Weight:  6,5 kg (net)