Creek Evo A 85 watt Integrated Amplifier

To achieve 85 Watts power into an 8 Ohms load and >160 Watts into 4 Ohms, the mains transformer has to be big. The Evo uses an over-rated 250VA toroidal transformer, which will provide enough current to drive the amplifier to almost double its output into 4 Ohms. To improve the sound quality, no expense has been spared.

Separate windings are used for each of the high current high voltage and low voltage, analogue and digital circuits. Two sets of rectifiers and a total of 20,000 micro-Farads of multiple smoothing capacitors are used to separate the left and right circuitry and improve the dynamic performance. This is a technique used by Creek before for its up-market products and is now available in the entry-level Evo. In terms of value for money, this cannot be over-stated.

Generally, few Hi-Fi companies put so much effort into their product's power supplies at this price point, but Creek knows that this is an area where the rewards are high for such investment. To allow it to be easily used in different countries, the Evo also uses an external voltage selector.

Significantly, the Evo is the first product made by Creek to use an electronic volume control. It uses a Burr-Brown PGA2311, stepped resistor attenuator operated by a microcontroller. This allows the user to adjust the volume accurately, in 1 dB steps, from 0 to -80dB. An analogue style rotary encoder, with 40mm solid control knob, is used to alter the volume from the front panel and display the reverse level in dB on a large blue coloured VFD display i.e. 80 is loudest and 0 is off. To buffer the signals in and out of the pre-amp, high grade Burr-Brown OPA2134 op-amps are used. Signal switching is performed by relays, which are driven by signal from a powerful microcontroller, similar to the Destiny amp.

The Evo is configured as a high open-loop gain circuit, using a double differential input and driver stage plus discrete Darlington power output stage, using high current bi-polar transistors. This is similar to the circuitry Creek used prior to its more complicated MOS-FET designs. High grade polypropylene capacitors, bypassed with large value electrolytics, are used to couple and decouple the signal into the power amp as the Evo doesn't use a DC servo correction, like the Classic and Destiny amps.

To keep the amplifier safe, it is monitored by discrete transistor circuitry to protect against over current demand, short circuits and DC offsets. Relays mute the input and separate the loudspeaker output in the case of faults.

The Evo operates conventionally with rotary controls for input selection and volume control and buttons for Tape selection and power On/off. It has four inputs plus tape - selection is via the remote handset or the input selection control. A visual indication of its status is displayed on a large blue Vacuum Fluorescent Display (VFD). The display brightness can be altered from the Evo remote control handset.

Gold plated input and output sockets have been chosen to provide a good connection and appearance for a product at its price point. Loudspeakers are connected with 1 set of 4mm terminal binding posts, with plastic touch proof covers. The amplifier also has a headphone socket which is becoming an increasingly rare feature of modern day amplifiers.

Mains connection is via a standard, fused, IEC chassis plug. A high quality power cord, with suitable mains plug for the country of use is supplied.


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