PRE-AMP

KingRex PRE-AMP -Blue Moon Award 2007 http://www.6moons.com/archivelibrary/bma2007.html

Key Feature

KingRex Pre-AMP has a hybrid design that improves on conventional voltage amplifiers with discrete components and high-performance op amps. It features two sets of line inputs with auto-select.

Appearance

The KingRex PRE-AMP shares the same aluminum faceplate, the same volume knob and the same chassis measurement of its sibling. The cabinet is of a rigid construction with elegantly appearance by the size 180*138*45mm with 6mm thick aluminum face plate which with polished sliver chrome volume control knob in the middle. The stylish design with the tiny size will bring fun for life. It also contributes to the touch and fell factor and is essential for the long lasting life even in a tough environment.

About the Jesrgh

About its design~ The key components include three pairs of Burr-Brown IC: OPA627 for pre-amplification (being a new generation FET(Difet)op amp, is recongnized for its low noise and high speed.), BUF634 for increasing and sustaining higher output current(BUF634 is not only a high speed op amp current booster, it also improves compatibility with power amp and loudspeakers), OPA177 for DC servo(OPA177 makes sure the op amp output is free of DC power, avoiding any chances of harming the power amp and the loudspeakers.It also has another advantage.It's not necessary to use extra output coupling capacitors and that improves the sonic performance a lot) On the power supply front, KingRex PRE-AMP is equipped with an 8VA toroidal transformer and a pair of National LM317T voltage regulators, delivering 13V/0.3A DC current to the circuit board. The Secret weapon is the unique design- plug-in PCB, Diamond Buffer circuit, which is a transistor-based all discrete-component buffering circuit that fine-tunes the incoming audio signal for frequency extension, tonal accuracy, holographic imaging and warm, tube-like atmosphere. Diamond buffer PCB mounted on top of the lower-deck main board through multi-pin connection. The advantage is this desigu is detachable.

PRE-AMP FEATURES

(1) The Pre-Amp us designed to use two sources. Each source is selected
automatically depending on which is outputing the signal. Switching is
carried out via a high quality relay. When using two sources ensure that the
one not being used is muted or turned off.

(2) Pre-Amp uses a low noise FET input OP-AMP. The highly-regarded and
expensive OPA627 is used as the main OP-AMP, with a BUF634 increasing the
current output. The addition of a DC servo circuit enables the elimination
of sound degrading coupling capacitors, resulting in a purer and more
accurate representation of the original source.

(3) A built-in 'diamond buffer' stage is added at the input to increase the
dynamic range of Pre-Amp.

(4) High quality gold-anodized phono input and output sockets are used.

(5) To encourage the owner to experiment with his/her preffered sound, we
have designed the Pre-Amp with socketed OP-AMPs. This allows the user to
change the OP-AMPs as/when new and better units become available.

(6) All this technology - including a dedicated torroidal transformer and
regulator circuitry for the PSU - is housed in a tiny and smart looking
case.

Circuit Path